Store private key in a file with the public keyname, get rid of argon2

13 files changed, 2205 insertions, 62 deletions

diff --git a/README.md b/README.md
index d59c504..6153e1d 100644
--- a/README.md
+++ b/README.md
@@ -41,7 +41,7 @@ To install `wg2nd`, please follow the instructions below based on your distribut
 ### Ubuntu/Debian
 
 ```bash
-sudo apt install build-essential libargon2-dev
+sudo apt install build-essential
 make
 sudo make install
 ```
@@ -49,7 +49,7 @@ sudo make install
 ### Arch Linux
 
 ```bash
-sudo pacman -S argon2 make gcc
+sudo pacman -S make gcc
 make
 sudo make install
 ```
diff --git a/makefile b/makefile
index d375869..7696611 100644
--- a/makefile
+++ b/makefile
@@ -8,20 +8,29 @@ endif
 
 # Compiler
 CXX = g++
+CC = gcc
+
+CFLAGS = -Wall -Wextra -Werror -Wno-unused-function
+CFLAGS += -Isrc
 
 # Compiler flags
-CXXFLAGS = -Wall -Wextra -Werror
-CXXFLAGS += -Isrc -std=c++20 -Wno-unused-function
+CXXFLAGS = $(CFLAGS)
+CXXFLAGS += -std=c++20
 
 # Release flags
-RELEASE_CXXFLAGS = -O3
+RELEASE_FLAGS = -O3
 RELEASE_LDFLAGS = -lrt
 
 # Debug flags
 DEBUGFLAGS = -ggdb -O0
 
 # Linking flags
-LDFLAGS = -largon2
+LDFLAGS =
+
+C_OBJECTS := src/crypto/encoding.o
+C_OBJECTS += src/crypto/curve25519.o
+C_OBJECTS += src/crypto/halfsiphash.o
+C_OBJECTS += src/crypto/pubkey.o
 
 # Object files
 OBJECTS := wg2nd.o
@@ -44,7 +53,8 @@ DEBUG_OBJ_DIR = obj/debug
 CMD = wg2nd
 
 # Build rules
-all: CXXFLAGS += $(RELEASE_CXXFLAGS)
+all: CXXFLAGS += $(RELEASE_FLAGS)
+all: CFLAGS += $(RELEASE_FLAGS)
 all: LDFLAGS += $(RELEASE_LDFLAGS)
 all: targets
 
@@ -56,12 +66,16 @@ debug: CXXFLAGS += $(DEBUGFLAGS)
 debug: OBJ_DIR = $(DEBUG_OBJ_DIR)
 debug: tests targets
 
-$(CMD): $(addprefix $(OBJ_DIR)/, $(OBJECTS))
+$(CMD): $(addprefix $(OBJ_DIR)/, $(OBJECTS)) $(C_OBJECTS)
 	$(CXX) $(CXXFLAGS) $^ $(LDFLAGS) -o $@
 
 $(OBJ_DIR)/%.o: $(SRC_DIR)/%.cpp | $(OBJ_DIR)
 	$(CXX) $(CXXFLAGS) -c $< -o $@
 
+$(C_OBJECTS): %.o: %.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+
 $(TEST_DIR)/%: $(TEST_DIR)/%.cpp $(addprefix $(OBJ_DIR)/, wg2nd.o) | $(OBJ_DIR)
 	$(CXX) $(CXXFLAGS) $^ $(LDFLAGS) -o $@
 
@@ -77,7 +91,7 @@ uninstall:
 
 # Clean rule
 clean:
-	rm -rf $(OBJ_DIR) $(DEBUG_OBJ_DIR) $(TARGET) $(TEST_TARGETS)
+	rm -rf $(OBJ_DIR) $(DEBUG_OBJ_DIR) $(TARGET) $(TEST_TARGETS) $(C_OBJECTS)
 
 .PHONY: install uninstall all clean targets tests
 
diff --git a/src/crypto/curve25519-fiat32.h b/src/crypto/curve25519-fiat32.h
new file mode 100644
index 0000000..66f3309
--- /dev/null
+++ b/src/crypto/curve25519-fiat32.h
@@ -0,0 +1,860 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Copyright (C) 2015-2016 The fiat-crypto Authors.
+ * Copyright (C) 2018-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * This is a machine-generated formally verified implementation of Curve25519
+ * ECDH from: <https://github.com/mit-plv/fiat-crypto>. Though originally
+ * machine generated, it has been tweaked to be suitable for use in the kernel.
+ * It is optimized for 32-bit machines and machines that cannot work efficiently
+ * with 128-bit integer types.
+ */
+
+/* fe means field element. Here the field is \Z/(2^255-19). An element t,
+ * entries t[0]...t[9], represents the integer t[0]+2^26 t[1]+2^51 t[2]+2^77
+ * t[3]+2^102 t[4]+...+2^230 t[9].
+ * fe limbs are bounded by 1.125*2^26,1.125*2^25,1.125*2^26,1.125*2^25,etc.
+ * Multiplication and carrying produce fe from fe_loose.
+ */
+typedef struct fe { u32 v[10]; } fe;
+
+/* fe_loose limbs are bounded by 3.375*2^26,3.375*2^25,3.375*2^26,3.375*2^25,etc
+ * Addition and subtraction produce fe_loose from (fe, fe).
+ */
+typedef struct fe_loose { u32 v[10]; } fe_loose;
+
+static __always_inline void fe_frombytes_impl(u32 h[10], const u8 *s)
+{
+	/* Ignores top bit of s. */
+	u32 a0 = get_unaligned_le32(s);
+	u32 a1 = get_unaligned_le32(s+4);
+	u32 a2 = get_unaligned_le32(s+8);
+	u32 a3 = get_unaligned_le32(s+12);
+	u32 a4 = get_unaligned_le32(s+16);
+	u32 a5 = get_unaligned_le32(s+20);
+	u32 a6 = get_unaligned_le32(s+24);
+	u32 a7 = get_unaligned_le32(s+28);
+	h[0] = a0&((1<<26)-1);                    /* 26 used, 32-26 left.   26 */
+	h[1] = (a0>>26) | ((a1&((1<<19)-1))<< 6); /* (32-26) + 19 =  6+19 = 25 */
+	h[2] = (a1>>19) | ((a2&((1<<13)-1))<<13); /* (32-19) + 13 = 13+13 = 26 */
+	h[3] = (a2>>13) | ((a3&((1<< 6)-1))<<19); /* (32-13) +  6 = 19+ 6 = 25 */
+	h[4] = (a3>> 6);                          /* (32- 6)              = 26 */
+	h[5] = a4&((1<<25)-1);                    /*                        25 */
+	h[6] = (a4>>25) | ((a5&((1<<19)-1))<< 7); /* (32-25) + 19 =  7+19 = 26 */
+	h[7] = (a5>>19) | ((a6&((1<<12)-1))<<13); /* (32-19) + 12 = 13+12 = 25 */
+	h[8] = (a6>>12) | ((a7&((1<< 6)-1))<<20); /* (32-12) +  6 = 20+ 6 = 26 */
+	h[9] = (a7>> 6)&((1<<25)-1); /*                                     25 */
+}
+
+static __always_inline void fe_frombytes(fe *h, const u8 *s)
+{
+	fe_frombytes_impl(h->v, s);
+}
+
+static __always_inline u8 /*bool*/
+addcarryx_u25(u8 /*bool*/ c, u32 a, u32 b, u32 *low)
+{
+	/* This function extracts 25 bits of result and 1 bit of carry
+	 * (26 total), so a 32-bit intermediate is sufficient.
+	 */
+	u32 x = a + b + c;
+	*low = x & ((1 << 25) - 1);
+	return (x >> 25) & 1;
+}
+
+static __always_inline u8 /*bool*/
+addcarryx_u26(u8 /*bool*/ c, u32 a, u32 b, u32 *low)
+{
+	/* This function extracts 26 bits of result and 1 bit of carry
+	 * (27 total), so a 32-bit intermediate is sufficient.
+	 */
+	u32 x = a + b + c;
+	*low = x & ((1 << 26) - 1);
+	return (x >> 26) & 1;
+}
+
+static __always_inline u8 /*bool*/
+subborrow_u25(u8 /*bool*/ c, u32 a, u32 b, u32 *low)
+{
+	/* This function extracts 25 bits of result and 1 bit of borrow
+	 * (26 total), so a 32-bit intermediate is sufficient.
+	 */
+	u32 x = a - b - c;
+	*low = x & ((1 << 25) - 1);
+	return x >> 31;
+}
+
+static __always_inline u8 /*bool*/
+subborrow_u26(u8 /*bool*/ c, u32 a, u32 b, u32 *low)
+{
+	/* This function extracts 26 bits of result and 1 bit of borrow
+	 *(27 total), so a 32-bit intermediate is sufficient.
+	 */
+	u32 x = a - b - c;
+	*low = x & ((1 << 26) - 1);
+	return x >> 31;
+}
+
+static __always_inline u32 cmovznz32(u32 t, u32 z, u32 nz)
+{
+	t = -!!t; /* all set if nonzero, 0 if 0 */
+	return (t&nz) | ((~t)&z);
+}
+
+static __always_inline void fe_freeze(u32 out[10], const u32 in1[10])
+{
+	{ const u32 x17 = in1[9];
+	{ const u32 x18 = in1[8];
+	{ const u32 x16 = in1[7];
+	{ const u32 x14 = in1[6];
+	{ const u32 x12 = in1[5];
+	{ const u32 x10 = in1[4];
+	{ const u32 x8 = in1[3];
+	{ const u32 x6 = in1[2];
+	{ const u32 x4 = in1[1];
+	{ const u32 x2 = in1[0];
+	{ u32 x20; u8/*bool*/ x21 = subborrow_u26(0x0, x2, 0x3ffffed, &x20);
+	{ u32 x23; u8/*bool*/ x24 = subborrow_u25(x21, x4, 0x1ffffff, &x23);
+	{ u32 x26; u8/*bool*/ x27 = subborrow_u26(x24, x6, 0x3ffffff, &x26);
+	{ u32 x29; u8/*bool*/ x30 = subborrow_u25(x27, x8, 0x1ffffff, &x29);
+	{ u32 x32; u8/*bool*/ x33 = subborrow_u26(x30, x10, 0x3ffffff, &x32);
+	{ u32 x35; u8/*bool*/ x36 = subborrow_u25(x33, x12, 0x1ffffff, &x35);
+	{ u32 x38; u8/*bool*/ x39 = subborrow_u26(x36, x14, 0x3ffffff, &x38);
+	{ u32 x41; u8/*bool*/ x42 = subborrow_u25(x39, x16, 0x1ffffff, &x41);
+	{ u32 x44; u8/*bool*/ x45 = subborrow_u26(x42, x18, 0x3ffffff, &x44);
+	{ u32 x47; u8/*bool*/ x48 = subborrow_u25(x45, x17, 0x1ffffff, &x47);
+	{ u32 x49 = cmovznz32(x48, 0x0, 0xffffffff);
+	{ u32 x50 = (x49 & 0x3ffffed);
+	{ u32 x52; u8/*bool*/ x53 = addcarryx_u26(0x0, x20, x50, &x52);
+	{ u32 x54 = (x49 & 0x1ffffff);
+	{ u32 x56; u8/*bool*/ x57 = addcarryx_u25(x53, x23, x54, &x56);
+	{ u32 x58 = (x49 & 0x3ffffff);
+	{ u32 x60; u8/*bool*/ x61 = addcarryx_u26(x57, x26, x58, &x60);
+	{ u32 x62 = (x49 & 0x1ffffff);
+	{ u32 x64; u8/*bool*/ x65 = addcarryx_u25(x61, x29, x62, &x64);
+	{ u32 x66 = (x49 & 0x3ffffff);
+	{ u32 x68; u8/*bool*/ x69 = addcarryx_u26(x65, x32, x66, &x68);
+	{ u32 x70 = (x49 & 0x1ffffff);
+	{ u32 x72; u8/*bool*/ x73 = addcarryx_u25(x69, x35, x70, &x72);
+	{ u32 x74 = (x49 & 0x3ffffff);
+	{ u32 x76; u8/*bool*/ x77 = addcarryx_u26(x73, x38, x74, &x76);
+	{ u32 x78 = (x49 & 0x1ffffff);
+	{ u32 x80; u8/*bool*/ x81 = addcarryx_u25(x77, x41, x78, &x80);
+	{ u32 x82 = (x49 & 0x3ffffff);
+	{ u32 x84; u8/*bool*/ x85 = addcarryx_u26(x81, x44, x82, &x84);
+	{ u32 x86 = (x49 & 0x1ffffff);
+	{ u32 x88; addcarryx_u25(x85, x47, x86, &x88);
+	out[0] = x52;
+	out[1] = x56;
+	out[2] = x60;
+	out[3] = x64;
+	out[4] = x68;
+	out[5] = x72;
+	out[6] = x76;
+	out[7] = x80;
+	out[8] = x84;
+	out[9] = x88;
+	}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}
+}
+
+static __always_inline void fe_tobytes(u8 s[32], const fe *f)
+{
+	u32 h[10];
+	fe_freeze(h, f->v);
+	s[0] = h[0] >> 0;
+	s[1] = h[0] >> 8;
+	s[2] = h[0] >> 16;
+	s[3] = (h[0] >> 24) | (h[1] << 2);
+	s[4] = h[1] >> 6;
+	s[5] = h[1] >> 14;
+	s[6] = (h[1] >> 22) | (h[2] << 3);
+	s[7] = h[2] >> 5;
+	s[8] = h[2] >> 13;
+	s[9] = (h[2] >> 21) | (h[3] << 5);
+	s[10] = h[3] >> 3;
+	s[11] = h[3] >> 11;
+	s[12] = (h[3] >> 19) | (h[4] << 6);
+	s[13] = h[4] >> 2;
+	s[14] = h[4] >> 10;
+	s[15] = h[4] >> 18;
+	s[16] = h[5] >> 0;
+	s[17] = h[5] >> 8;
+	s[18] = h[5] >> 16;
+	s[19] = (h[5] >> 24) | (h[6] << 1);
+	s[20] = h[6] >> 7;
+	s[21] = h[6] >> 15;
+	s[22] = (h[6] >> 23) | (h[7] << 3);
+	s[23] = h[7] >> 5;
+	s[24] = h[7] >> 13;
+	s[25] = (h[7] >> 21) | (h[8] << 4);
+	s[26] = h[8] >> 4;
+	s[27] = h[8] >> 12;
+	s[28] = (h[8] >> 20) | (h[9] << 6);
+	s[29] = h[9] >> 2;
+	s[30] = h[9] >> 10;
+	s[31] = h[9] >> 18;
+}
+
+/* h = f */
+static __always_inline void fe_copy(fe *h, const fe *f)
+{
+	memmove(h, f, sizeof(u32) * 10);
+}
+
+static __always_inline void fe_copy_lt(fe_loose *h, const fe *f)
+{
+	memmove(h, f, sizeof(u32) * 10);
+}
+
+/* h = 0 */
+static __always_inline void fe_0(fe *h)
+{
+	memset(h, 0, sizeof(u32) * 10);
+}
+
+/* h = 1 */
+static __always_inline void fe_1(fe *h)
+{
+	memset(h, 0, sizeof(u32) * 10);
+	h->v[0] = 1;
+}
+
+static void fe_add_impl(u32 out[10], const u32 in1[10], const u32 in2[10])
+{
+	{ const u32 x20 = in1[9];
+	{ const u32 x21 = in1[8];
+	{ const u32 x19 = in1[7];
+	{ const u32 x17 = in1[6];
+	{ const u32 x15 = in1[5];
+	{ const u32 x13 = in1[4];
+	{ const u32 x11 = in1[3];
+	{ const u32 x9 = in1[2];
+	{ const u32 x7 = in1[1];
+	{ const u32 x5 = in1[0];
+	{ const u32 x38 = in2[9];
+	{ const u32 x39 = in2[8];
+	{ const u32 x37 = in2[7];
+	{ const u32 x35 = in2[6];
+	{ const u32 x33 = in2[5];
+	{ const u32 x31 = in2[4];
+	{ const u32 x29 = in2[3];
+	{ const u32 x27 = in2[2];
+	{ const u32 x25 = in2[1];
+	{ const u32 x23 = in2[0];
+	out[0] = (x5 + x23);
+	out[1] = (x7 + x25);
+	out[2] = (x9 + x27);
+	out[3] = (x11 + x29);
+	out[4] = (x13 + x31);
+	out[5] = (x15 + x33);
+	out[6] = (x17 + x35);
+	out[7] = (x19 + x37);
+	out[8] = (x21 + x39);
+	out[9] = (x20 + x38);
+	}}}}}}}}}}}}}}}}}}}}
+}
+
+/* h = f + g
+ * Can overlap h with f or g.
+ */
+static __always_inline void fe_add(fe_loose *h, const fe *f, const fe *g)
+{
+	fe_add_impl(h->v, f->v, g->v);
+}
+
+static void fe_sub_impl(u32 out[10], const u32 in1[10], const u32 in2[10])
+{
+	{ const u32 x20 = in1[9];
+	{ const u32 x21 = in1[8];
+	{ const u32 x19 = in1[7];
+	{ const u32 x17 = in1[6];
+	{ const u32 x15 = in1[5];
+	{ const u32 x13 = in1[4];
+	{ const u32 x11 = in1[3];
+	{ const u32 x9 = in1[2];
+	{ const u32 x7 = in1[1];
+	{ const u32 x5 = in1[0];
+	{ const u32 x38 = in2[9];
+	{ const u32 x39 = in2[8];
+	{ const u32 x37 = in2[7];
+	{ const u32 x35 = in2[6];
+	{ const u32 x33 = in2[5];
+	{ const u32 x31 = in2[4];
+	{ const u32 x29 = in2[3];
+	{ const u32 x27 = in2[2];
+	{ const u32 x25 = in2[1];
+	{ const u32 x23 = in2[0];
+	out[0] = ((0x7ffffda + x5) - x23);
+	out[1] = ((0x3fffffe + x7) - x25);
+	out[2] = ((0x7fffffe + x9) - x27);
+	out[3] = ((0x3fffffe + x11) - x29);
+	out[4] = ((0x7fffffe + x13) - x31);
+	out[5] = ((0x3fffffe + x15) - x33);
+	out[6] = ((0x7fffffe + x17) - x35);
+	out[7] = ((0x3fffffe + x19) - x37);
+	out[8] = ((0x7fffffe + x21) - x39);
+	out[9] = ((0x3fffffe + x20) - x38);
+	}}}}}}}}}}}}}}}}}}}}
+}
+
+/* h = f - g
+ * Can overlap h with f or g.
+ */
+static __always_inline void fe_sub(fe_loose *h, const fe *f, const fe *g)
+{
+	fe_sub_impl(h->v, f->v, g->v);
+}
+
+static void fe_mul_impl(u32 out[10], const u32 in1[10], const u32 in2[10])
+{
+	{ const u32 x20 = in1[9];
+	{ const u32 x21 = in1[8];
+	{ const u32 x19 = in1[7];
+	{ const u32 x17 = in1[6];
+	{ const u32 x15 = in1[5];
+	{ const u32 x13 = in1[4];
+	{ const u32 x11 = in1[3];
+	{ const u32 x9 = in1[2];
+	{ const u32 x7 = in1[1];
+	{ const u32 x5 = in1[0];
+	{ const u32 x38 = in2[9];
+	{ const u32 x39 = in2[8];
+	{ const u32 x37 = in2[7];
+	{ const u32 x35 = in2[6];
+	{ const u32 x33 = in2[5];
+	{ const u32 x31 = in2[4];
+	{ const u32 x29 = in2[3];
+	{ const u32 x27 = in2[2];
+	{ const u32 x25 = in2[1];
+	{ const u32 x23 = in2[0];
+	{ u64 x40 = ((u64)x23 * x5);
+	{ u64 x41 = (((u64)x23 * x7) + ((u64)x25 * x5));
+	{ u64 x42 = ((((u64)(0x2 * x25) * x7) + ((u64)x23 * x9)) + ((u64)x27 * x5));
+	{ u64 x43 = (((((u64)x25 * x9) + ((u64)x27 * x7)) + ((u64)x23 * x11)) + ((u64)x29 * x5));
+	{ u64 x44 = (((((u64)x27 * x9) + (0x2 * (((u64)x25 * x11) + ((u64)x29 * x7)))) + ((u64)x23 * x13)) + ((u64)x31 * x5));
+	{ u64 x45 = (((((((u64)x27 * x11) + ((u64)x29 * x9)) + ((u64)x25 * x13)) + ((u64)x31 * x7)) + ((u64)x23 * x15)) + ((u64)x33 * x5));
+	{ u64 x46 = (((((0x2 * ((((u64)x29 * x11) + ((u64)x25 * x15)) + ((u64)x33 * x7))) + ((u64)x27 * x13)) + ((u64)x31 * x9)) + ((u64)x23 * x17)) + ((u64)x35 * x5));
+	{ u64 x47 = (((((((((u64)x29 * x13) + ((u64)x31 * x11)) + ((u64)x27 * x15)) + ((u64)x33 * x9)) + ((u64)x25 * x17)) + ((u64)x35 * x7)) + ((u64)x23 * x19)) + ((u64)x37 * x5));
+	{ u64 x48 = (((((((u64)x31 * x13) + (0x2 * (((((u64)x29 * x15) + ((u64)x33 * x11)) + ((u64)x25 * x19)) + ((u64)x37 * x7)))) + ((u64)x27 * x17)) + ((u64)x35 * x9)) + ((u64)x23 * x21)) + ((u64)x39 * x5));
+	{ u64 x49 = (((((((((((u64)x31 * x15) + ((u64)x33 * x13)) + ((u64)x29 * x17)) + ((u64)x35 * x11)) + ((u64)x27 * x19)) + ((u64)x37 * x9)) + ((u64)x25 * x21)) + ((u64)x39 * x7)) + ((u64)x23 * x20)) + ((u64)x38 * x5));
+	{ u64 x50 = (((((0x2 * ((((((u64)x33 * x15) + ((u64)x29 * x19)) + ((u64)x37 * x11)) + ((u64)x25 * x20)) + ((u64)x38 * x7))) + ((u64)x31 * x17)) + ((u64)x35 * x13)) + ((u64)x27 * x21)) + ((u64)x39 * x9));
+	{ u64 x51 = (((((((((u64)x33 * x17) + ((u64)x35 * x15)) + ((u64)x31 * x19)) + ((u64)x37 * x13)) + ((u64)x29 * x21)) + ((u64)x39 * x11)) + ((u64)x27 * x20)) + ((u64)x38 * x9));
+	{ u64 x52 = (((((u64)x35 * x17) + (0x2 * (((((u64)x33 * x19) + ((u64)x37 * x15)) + ((u64)x29 * x20)) + ((u64)x38 * x11)))) + ((u64)x31 * x21)) + ((u64)x39 * x13));
+	{ u64 x53 = (((((((u64)x35 * x19) + ((u64)x37 * x17)) + ((u64)x33 * x21)) + ((u64)x39 * x15)) + ((u64)x31 * x20)) + ((u64)x38 * x13));
+	{ u64 x54 = (((0x2 * ((((u64)x37 * x19) + ((u64)x33 * x20)) + ((u64)x38 * x15))) + ((u64)x35 * x21)) + ((u64)x39 * x17));
+	{ u64 x55 = (((((u64)x37 * x21) + ((u64)x39 * x19)) + ((u64)x35 * x20)) + ((u64)x38 * x17));
+	{ u64 x56 = (((u64)x39 * x21) + (0x2 * (((u64)x37 * x20) + ((u64)x38 * x19))));
+	{ u64 x57 = (((u64)x39 * x20) + ((u64)x38 * x21));
+	{ u64 x58 = ((u64)(0x2 * x38) * x20);
+	{ u64 x59 = (x48 + (x58 << 0x4));
+	{ u64 x60 = (x59 + (x58 << 0x1));
+	{ u64 x61 = (x60 + x58);
+	{ u64 x62 = (x47 + (x57 << 0x4));
+	{ u64 x63 = (x62 + (x57 << 0x1));
+	{ u64 x64 = (x63 + x57);
+	{ u64 x65 = (x46 + (x56 << 0x4));
+	{ u64 x66 = (x65 + (x56 << 0x1));
+	{ u64 x67 = (x66 + x56);
+	{ u64 x68 = (x45 + (x55 << 0x4));
+	{ u64 x69 = (x68 + (x55 << 0x1));
+	{ u64 x70 = (x69 + x55);
+	{ u64 x71 = (x44 + (x54 << 0x4));
+	{ u64 x72 = (x71 + (x54 << 0x1));
+	{ u64 x73 = (x72 + x54);
+	{ u64 x74 = (x43 + (x53 << 0x4));
+	{ u64 x75 = (x74 + (x53 << 0x1));
+	{ u64 x76 = (x75 + x53);
+	{ u64 x77 = (x42 + (x52 << 0x4));
+	{ u64 x78 = (x77 + (x52 << 0x1));
+	{ u64 x79 = (x78 + x52);
+	{ u64 x80 = (x41 + (x51 << 0x4));
+	{ u64 x81 = (x80 + (x51 << 0x1));
+	{ u64 x82 = (x81 + x51);
+	{ u64 x83 = (x40 + (x50 << 0x4));
+	{ u64 x84 = (x83 + (x50 << 0x1));
+	{ u64 x85 = (x84 + x50);
+	{ u64 x86 = (x85 >> 0x1a);
+	{ u32 x87 = ((u32)x85 & 0x3ffffff);
+	{ u64 x88 = (x86 + x82);
+	{ u64 x89 = (x88 >> 0x19);
+	{ u32 x90 = ((u32)x88 & 0x1ffffff);
+	{ u64 x91 = (x89 + x79);
+	{ u64 x92 = (x91 >> 0x1a);
+	{ u32 x93 = ((u32)x91 & 0x3ffffff);
+	{ u64 x94 = (x92 + x76);
+	{ u64 x95 = (x94 >> 0x19);
+	{ u32 x96 = ((u32)x94 & 0x1ffffff);
+	{ u64 x97 = (x95 + x73);
+	{ u64 x98 = (x97 >> 0x1a);
+	{ u32 x99 = ((u32)x97 & 0x3ffffff);
+	{ u64 x100 = (x98 + x70);
+	{ u64 x101 = (x100 >> 0x19);
+	{ u32 x102 = ((u32)x100 & 0x1ffffff);
+	{ u64 x103 = (x101 + x67);
+	{ u64 x104 = (x103 >> 0x1a);
+	{ u32 x105 = ((u32)x103 & 0x3ffffff);
+	{ u64 x106 = (x104 + x64);
+	{ u64 x107 = (x106 >> 0x19);
+	{ u32 x108 = ((u32)x106 & 0x1ffffff);
+	{ u64 x109 = (x107 + x61);
+	{ u64 x110 = (x109 >> 0x1a);
+	{ u32 x111 = ((u32)x109 & 0x3ffffff);
+	{ u64 x112 = (x110 + x49);
+	{ u64 x113 = (x112 >> 0x19);
+	{ u32 x114 = ((u32)x112 & 0x1ffffff);
+	{ u64 x115 = (x87 + (0x13 * x113));
+	{ u32 x116 = (u32) (x115 >> 0x1a);
+	{ u32 x117 = ((u32)x115 & 0x3ffffff);
+	{ u32 x118 = (x116 + x90);
+	{ u32 x119 = (x118 >> 0x19);
+	{ u32 x120 = (x118 & 0x1ffffff);
+	out[0] = x117;
+	out[1] = x120;
+	out[2] = (x119 + x93);
+	out[3] = x96;
+	out[4] = x99;
+	out[5] = x102;
+	out[6] = x105;
+	out[7] = x108;
+	out[8] = x111;
+	out[9] = x114;
+	}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}
+}
+
+static __always_inline void fe_mul_ttt(fe *h, const fe *f, const fe *g)
+{
+	fe_mul_impl(h->v, f->v, g->v);
+}
+
+static __always_inline void fe_mul_tlt(fe *h, const fe_loose *f, const fe *g)
+{
+	fe_mul_impl(h->v, f->v, g->v);
+}
+
+static __always_inline void
+fe_mul_tll(fe *h, const fe_loose *f, const fe_loose *g)
+{
+	fe_mul_impl(h->v, f->v, g->v);
+}
+
+static void fe_sqr_impl(u32 out[10], const u32 in1[10])
+{
+	{ const u32 x17 = in1[9];
+	{ const u32 x18 = in1[8];
+	{ const u32 x16 = in1[7];
+	{ const u32 x14 = in1[6];
+	{ const u32 x12 = in1[5];
+	{ const u32 x10 = in1[4];
+	{ const u32 x8 = in1[3];
+	{ const u32 x6 = in1[2];
+	{ const u32 x4 = in1[1];
+	{ const u32 x2 = in1[0];
+	{ u64 x19 = ((u64)x2 * x2);
+	{ u64 x20 = ((u64)(0x2 * x2) * x4);
+	{ u64 x21 = (0x2 * (((u64)x4 * x4) + ((u64)x2 * x6)));
+	{ u64 x22 = (0x2 * (((u64)x4 * x6) + ((u64)x2 * x8)));
+	{ u64 x23 = ((((u64)x6 * x6) + ((u64)(0x4 * x4) * x8)) + ((u64)(0x2 * x2) * x10));
+	{ u64 x24 = (0x2 * ((((u64)x6 * x8) + ((u64)x4 * x10)) + ((u64)x2 * x12)));
+	{ u64 x25 = (0x2 * (((((u64)x8 * x8) + ((u64)x6 * x10)) + ((u64)x2 * x14)) + ((u64)(0x2 * x4) * x12)));
+	{ u64 x26 = (0x2 * (((((u64)x8 * x10) + ((u64)x6 * x12)) + ((u64)x4 * x14)) + ((u64)x2 * x16)));
+	{ u64 x27 = (((u64)x10 * x10) + (0x2 * ((((u64)x6 * x14) + ((u64)x2 * x18)) + (0x2 * (((u64)x4 * x16) + ((u64)x8 * x12))))));
+	{ u64 x28 = (0x2 * ((((((u64)x10 * x12) + ((u64)x8 * x14)) + ((u64)x6 * x16)) + ((u64)x4 * x18)) + ((u64)x2 * x17)));
+	{ u64 x29 = (0x2 * (((((u64)x12 * x12) + ((u64)x10 * x14)) + ((u64)x6 * x18)) + (0x2 * (((u64)x8 * x16) + ((u64)x4 * x17)))));
+	{ u64 x30 = (0x2 * (((((u64)x12 * x14) + ((u64)x10 * x16)) + ((u64)x8 * x18)) + ((u64)x6 * x17)));
+	{ u64 x31 = (((u64)x14 * x14) + (0x2 * (((u64)x10 * x18) + (0x2 * (((u64)x12 * x16) + ((u64)x8 * x17))))));
+	{ u64 x32 = (0x2 * ((((u64)x14 * x16) + ((u64)x12 * x18)) + ((u64)x10 * x17)));
+	{ u64 x33 = (0x2 * ((((u64)x16 * x16) + ((u64)x14 * x18)) + ((u64)(0x2 * x12) * x17)));
+	{ u64 x34 = (0x2 * (((u64)x16 * x18) + ((u64)x14 * x17)));
+	{ u64 x35 = (((u64)x18 * x18) + ((u64)(0x4 * x16) * x17));
+	{ u64 x36 = ((u64)(0x2 * x18) * x17);
+	{ u64 x37 = ((u64)(0x2 * x17) * x17);
+	{ u64 x38 = (x27 + (x37 << 0x4));
+	{ u64 x39 = (x38 + (x37 << 0x1));
+	{ u64 x40 = (x39 + x37);
+	{ u64 x41 = (x26 + (x36 << 0x4));
+	{ u64 x42 = (x41 + (x36 << 0x1));
+	{ u64 x43 = (x42 + x36);
+	{ u64 x44 = (x25 + (x35 << 0x4));
+	{ u64 x45 = (x44 + (x35 << 0x1));
+	{ u64 x46 = (x45 + x35);
+	{ u64 x47 = (x24 + (x34 << 0x4));
+	{ u64 x48 = (x47 + (x34 << 0x1));
+	{ u64 x49 = (x48 + x34);
+	{ u64 x50 = (x23 + (x33 << 0x4));
+	{ u64 x51 = (x50 + (x33 << 0x1));
+	{ u64 x52 = (x51 + x33);
+	{ u64 x53 = (x22 + (x32 << 0x4));
+	{ u64 x54 = (x53 + (x32 << 0x1));
+	{ u64 x55 = (x54 + x32);
+	{ u64 x56 = (x21 + (x31 << 0x4));
+	{ u64 x57 = (x56 + (x31 << 0x1));
+	{ u64 x58 = (x57 + x31);
+	{ u64 x59 = (x20 + (x30 << 0x4));
+	{ u64 x60 = (x59 + (x30 << 0x1));
+	{ u64 x61 = (x60 + x30);
+	{ u64 x62 = (x19 + (x29 << 0x4));
+	{ u64 x63 = (x62 + (x29 << 0x1));
+	{ u64 x64 = (x63 + x29);
+	{ u64 x65 = (x64 >> 0x1a);
+	{ u32 x66 = ((u32)x64 & 0x3ffffff);
+	{ u64 x67 = (x65 + x61);
+	{ u64 x68 = (x67 >> 0x19);
+	{ u32 x69 = ((u32)x67 & 0x1ffffff);
+	{ u64 x70 = (x68 + x58);
+	{ u64 x71 = (x70 >> 0x1a);
+	{ u32 x72 = ((u32)x70 & 0x3ffffff);
+	{ u64 x73 = (x71 + x55);
+	{ u64 x74 = (x73 >> 0x19);
+	{ u32 x75 = ((u32)x73 & 0x1ffffff);
+	{ u64 x76 = (x74 + x52);
+	{ u64 x77 = (x76 >> 0x1a);
+	{ u32 x78 = ((u32)x76 & 0x3ffffff);
+	{ u64 x79 = (x77 + x49);
+	{ u64 x80 = (x79 >> 0x19);
+	{ u32 x81 = ((u32)x79 & 0x1ffffff);
+	{ u64 x82 = (x80 + x46);
+	{ u64 x83 = (x82 >> 0x1a);
+	{ u32 x84 = ((u32)x82 & 0x3ffffff);
+	{ u64 x85 = (x83 + x43);
+	{ u64 x86 = (x85 >> 0x19);
+	{ u32 x87 = ((u32)x85 & 0x1ffffff);
+	{ u64 x88 = (x86 + x40);
+	{ u64 x89 = (x88 >> 0x1a);
+	{ u32 x90 = ((u32)x88 & 0x3ffffff);
+	{ u64 x91 = (x89 + x28);
+	{ u64 x92 = (x91 >> 0x19);
+	{ u32 x93 = ((u32)x91 & 0x1ffffff);
+	{ u64 x94 = (x66 + (0x13 * x92));
+	{ u32 x95 = (u32) (x94 >> 0x1a);
+	{ u32 x96 = ((u32)x94 & 0x3ffffff);
+	{ u32 x97 = (x95 + x69);
+	{ u32 x98 = (x97 >> 0x19);
+	{ u32 x99 = (x97 & 0x1ffffff);
+	out[0] = x96;
+	out[1] = x99;
+	out[2] = (x98 + x72);
+	out[3] = x75;
+	out[4] = x78;
+	out[5] = x81;
+	out[6] = x84;
+	out[7] = x87;
+	out[8] = x90;
+	out[9] = x93;
+	}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}
+}
+
+static __always_inline void fe_sq_tl(fe *h, const fe_loose *f)
+{
+	fe_sqr_impl(h->v, f->v);
+}
+
+static __always_inline void fe_sq_tt(fe *h, const fe *f)
+{
+	fe_sqr_impl(h->v, f->v);
+}
+
+static __always_inline void fe_loose_invert(fe *out, const fe_loose *z)
+{
+	fe t0;
+	fe t1;
+	fe t2;
+	fe t3;
+	int i;
+
+	fe_sq_tl(&t0, z);
+	fe_sq_tt(&t1, &t0);
+	for (i = 1; i < 2; ++i)
+		fe_sq_tt(&t1, &t1);
+	fe_mul_tlt(&t1, z, &t1);
+	fe_mul_ttt(&t0, &t0, &t1);
+	fe_sq_tt(&t2, &t0);
+	fe_mul_ttt(&t1, &t1, &t2);
+	fe_sq_tt(&t2, &t1);
+	for (i = 1; i < 5; ++i)
+		fe_sq_tt(&t2, &t2);
+	fe_mul_ttt(&t1, &t2, &t1);
+	fe_sq_tt(&t2, &t1);
+	for (i = 1; i < 10; ++i)
+		fe_sq_tt(&t2, &t2);
+	fe_mul_ttt(&t2, &t2, &t1);
+	fe_sq_tt(&t3, &t2);
+	for (i = 1; i < 20; ++i)
+		fe_sq_tt(&t3, &t3);
+	fe_mul_ttt(&t2, &t3, &t2);
+	fe_sq_tt(&t2, &t2);
+	for (i = 1; i < 10; ++i)
+		fe_sq_tt(&t2, &t2);
+	fe_mul_ttt(&t1, &t2, &t1);
+	fe_sq_tt(&t2, &t1);
+	for (i = 1; i < 50; ++i)
+		fe_sq_tt(&t2, &t2);
+	fe_mul_ttt(&t2, &t2, &t1);
+	fe_sq_tt(&t3, &t2);
+	for (i = 1; i < 100; ++i)
+		fe_sq_tt(&t3, &t3);
+	fe_mul_ttt(&t2, &t3, &t2);
+	fe_sq_tt(&t2, &t2);
+	for (i = 1; i < 50; ++i)
+		fe_sq_tt(&t2, &t2);
+	fe_mul_ttt(&t1, &t2, &t1);
+	fe_sq_tt(&t1, &t1);
+	for (i = 1; i < 5; ++i)
+		fe_sq_tt(&t1, &t1);
+	fe_mul_ttt(out, &t1, &t0);
+}
+
+static __always_inline void fe_invert(fe *out, const fe *z)
+{
+	fe_loose l;
+	fe_copy_lt(&l, z);
+	fe_loose_invert(out, &l);
+}
+
+/* Replace (f,g) with (g,f) if b == 1;
+ * replace (f,g) with (f,g) if b == 0.
+ *
+ * Preconditions: b in {0,1}
+ */
+static __always_inline void fe_cswap(fe *f, fe *g, unsigned int b)
+{
+	unsigned i;
+	b = 0 - b;
+	for (i = 0; i < 10; i++) {
+		u32 x = f->v[i] ^ g->v[i];
+		x &= b;
+		f->v[i] ^= x;
+		g->v[i] ^= x;
+	}
+}
+
+/* NOTE: based on fiat-crypto fe_mul, edited for in2=121666, 0, 0.*/
+static __always_inline void fe_mul_121666_impl(u32 out[10], const u32 in1[10])
+{
+	{ const u32 x20 = in1[9];
+	{ const u32 x21 = in1[8];
+	{ const u32 x19 = in1[7];
+	{ const u32 x17 = in1[6];
+	{ const u32 x15 = in1[5];
+	{ const u32 x13 = in1[4];
+	{ const u32 x11 = in1[3];
+	{ const u32 x9 = in1[2];
+	{ const u32 x7 = in1[1];
+	{ const u32 x5 = in1[0];
+	{ const u32 x38 = 0;
+	{ const u32 x39 = 0;
+	{ const u32 x37 = 0;
+	{ const u32 x35 = 0;
+	{ const u32 x33 = 0;
+	{ const u32 x31 = 0;
+	{ const u32 x29 = 0;
+	{ const u32 x27 = 0;
+	{ const u32 x25 = 0;
+	{ const u32 x23 = 121666;
+	{ u64 x40 = ((u64)x23 * x5);
+	{ u64 x41 = (((u64)x23 * x7) + ((u64)x25 * x5));
+	{ u64 x42 = ((((u64)(0x2 * x25) * x7) + ((u64)x23 * x9)) + ((u64)x27 * x5));
+	{ u64 x43 = (((((u64)x25 * x9) + ((u64)x27 * x7)) + ((u64)x23 * x11)) + ((u64)x29 * x5));
+	{ u64 x44 = (((((u64)x27 * x9) + (0x2 * (((u64)x25 * x11) + ((u64)x29 * x7)))) + ((u64)x23 * x13)) + ((u64)x31 * x5));
+	{ u64 x45 = (((((((u64)x27 * x11) + ((u64)x29 * x9)) + ((u64)x25 * x13)) + ((u64)x31 * x7)) + ((u64)x23 * x15)) + ((u64)x33 * x5));
+	{ u64 x46 = (((((0x2 * ((((u64)x29 * x11) + ((u64)x25 * x15)) + ((u64)x33 * x7))) + ((u64)x27 * x13)) + ((u64)x31 * x9)) + ((u64)x23 * x17)) + ((u64)x35 * x5));
+	{ u64 x47 = (((((((((u64)x29 * x13) + ((u64)x31 * x11)) + ((u64)x27 * x15)) + ((u64)x33 * x9)) + ((u64)x25 * x17)) + ((u64)x35 * x7)) + ((u64)x23 * x19)) + ((u64)x37 * x5));
+	{ u64 x48 = (((((((u64)x31 * x13) + (0x2 * (((((u64)x29 * x15) + ((u64)x33 * x11)) + ((u64)x25 * x19)) + ((u64)x37 * x7)))) + ((u64)x27 * x17)) + ((u64)x35 * x9)) + ((u64)x23 * x21)) + ((u64)x39 * x5));
+	{ u64 x49 = (((((((((((u64)x31 * x15) + ((u64)x33 * x13)) + ((u64)x29 * x17)) + ((u64)x35 * x11)) + ((u64)x27 * x19)) + ((u64)x37 * x9)) + ((u64)x25 * x21)) + ((u64)x39 * x7)) + ((u64)x23 * x20)) + ((u64)x38 * x5));
+	{ u64 x50 = (((((0x2 * ((((((u64)x33 * x15) + ((u64)x29 * x19)) + ((u64)x37 * x11)) + ((u64)x25 * x20)) + ((u64)x38 * x7))) + ((u64)x31 * x17)) + ((u64)x35 * x13)) + ((u64)x27 * x21)) + ((u64)x39 * x9));
+	{ u64 x51 = (((((((((u64)x33 * x17) + ((u64)x35 * x15)) + ((u64)x31 * x19)) + ((u64)x37 * x13)) + ((u64)x29 * x21)) + ((u64)x39 * x11)) + ((u64)x27 * x20)) + ((u64)x38 * x9));
+	{ u64 x52 = (((((u64)x35 * x17) + (0x2 * (((((u64)x33 * x19) + ((u64)x37 * x15)) + ((u64)x29 * x20)) + ((u64)x38 * x11)))) + ((u64)x31 * x21)) + ((u64)x39 * x13));
+	{ u64 x53 = (((((((u64)x35 * x19) + ((u64)x37 * x17)) + ((u64)x33 * x21)) + ((u64)x39 * x15)) + ((u64)x31 * x20)) + ((u64)x38 * x13));
+	{ u64 x54 = (((0x2 * ((((u64)x37 * x19) + ((u64)x33 * x20)) + ((u64)x38 * x15))) + ((u64)x35 * x21)) + ((u64)x39 * x17));
+	{ u64 x55 = (((((u64)x37 * x21) + ((u64)x39 * x19)) + ((u64)x35 * x20)) + ((u64)x38 * x17));
+	{ u64 x56 = (((u64)x39 * x21) + (0x2 * (((u64)x37 * x20) + ((u64)x38 * x19))));
+	{ u64 x57 = (((u64)x39 * x20) + ((u64)x38 * x21));
+	{ u64 x58 = ((u64)(0x2 * x38) * x20);
+	{ u64 x59 = (x48 + (x58 << 0x4));
+	{ u64 x60 = (x59 + (x58 << 0x1));
+	{ u64 x61 = (x60 + x58);
+	{ u64 x62 = (x47 + (x57 << 0x4));
+	{ u64 x63 = (x62 + (x57 << 0x1));
+	{ u64 x64 = (x63 + x57);
+	{ u64 x65 = (x46 + (x56 << 0x4));
+	{ u64 x66 = (x65 + (x56 << 0x1));
+	{ u64 x67 = (x66 + x56);
+	{ u64 x68 = (x45 + (x55 << 0x4));
+	{ u64 x69 = (x68 + (x55 << 0x1));
+	{ u64 x70 = (x69 + x55);
+	{ u64 x71 = (x44 + (x54 << 0x4));
+	{ u64 x72 = (x71 + (x54 << 0x1));
+	{ u64 x73 = (x72 + x54);
+	{ u64 x74 = (x43 + (x53 << 0x4));
+	{ u64 x75 = (x74 + (x53 << 0x1));
+	{ u64 x76 = (x75 + x53);
+	{ u64 x77 = (x42 + (x52 << 0x4));
+	{ u64 x78 = (x77 + (x52 << 0x1));
+	{ u64 x79 = (x78 + x52);
+	{ u64 x80 = (x41 + (x51 << 0x4));
+	{ u64 x81 = (x80 + (x51 << 0x1));
+	{ u64 x82 = (x81 + x51);
+	{ u64 x83 = (x40 + (x50 << 0x4));
+	{ u64 x84 = (x83 + (x50 << 0x1));
+	{ u64 x85 = (x84 + x50);
+	{ u64 x86 = (x85 >> 0x1a);
+	{ u32 x87 = ((u32)x85 & 0x3ffffff);
+	{ u64 x88 = (x86 + x82);
+	{ u64 x89 = (x88 >> 0x19);
+	{ u32 x90 = ((u32)x88 & 0x1ffffff);
+	{ u64 x91 = (x89 + x79);
+	{ u64 x92 = (x91 >> 0x1a);
+	{ u32 x93 = ((u32)x91 & 0x3ffffff);
+	{ u64 x94 = (x92 + x76);
+	{ u64 x95 = (x94 >> 0x19);
+	{ u32 x96 = ((u32)x94 & 0x1ffffff);
+	{ u64 x97 = (x95 + x73);
+	{ u64 x98 = (x97 >> 0x1a);
+	{ u32 x99 = ((u32)x97 & 0x3ffffff);
+	{ u64 x100 = (x98 + x70);
+	{ u64 x101 = (x100 >> 0x19);
+	{ u32 x102 = ((u32)x100 & 0x1ffffff);
+	{ u64 x103 = (x101 + x67);
+	{ u64 x104 = (x103 >> 0x1a);
+	{ u32 x105 = ((u32)x103 & 0x3ffffff);
+	{ u64 x106 = (x104 + x64);
+	{ u64 x107 = (x106 >> 0x19);
+	{ u32 x108 = ((u32)x106 & 0x1ffffff);
+	{ u64 x109 = (x107 + x61);
+	{ u64 x110 = (x109 >> 0x1a);
+	{ u32 x111 = ((u32)x109 & 0x3ffffff);
+	{ u64 x112 = (x110 + x49);
+	{ u64 x113 = (x112 >> 0x19);
+	{ u32 x114 = ((u32)x112 & 0x1ffffff);
+	{ u64 x115 = (x87 + (0x13 * x113));
+	{ u32 x116 = (u32) (x115 >> 0x1a);
+	{ u32 x117 = ((u32)x115 & 0x3ffffff);
+	{ u32 x118 = (x116 + x90);
+	{ u32 x119 = (x118 >> 0x19);
+	{ u32 x120 = (x118 & 0x1ffffff);
+	out[0] = x117;
+	out[1] = x120;
+	out[2] = (x119 + x93);
+	out[3] = x96;
+	out[4] = x99;
+	out[5] = x102;
+	out[6] = x105;
+	out[7] = x108;
+	out[8] = x111;
+	out[9] = x114;
+	}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}
+}
+
+static __always_inline void fe_mul121666(fe *h, const fe_loose *f)
+{
+	fe_mul_121666_impl(h->v, f->v);
+}
+
+static void curve25519_generic(u8 out[CURVE25519_KEY_SIZE],
+			       const u8 scalar[CURVE25519_KEY_SIZE],
+			       const u8 point[CURVE25519_KEY_SIZE])
+{
+	fe x1, x2, z2, x3, z3;
+	fe_loose x2l, z2l, x3l;
+	unsigned swap = 0;
+	int pos;
+	u8 e[32];
+
+	memcpy(e, scalar, 32);
+	curve25519_clamp_secret(e);
+
+	/* The following implementation was transcribed to Coq and proven to
+	 * correspond to unary scalar multiplication in affine coordinates given
+	 * that x1 != 0 is the x coordinate of some point on the curve. It was
+	 * also checked in Coq that doing a ladderstep with x1 = x3 = 0 gives
+	 * z2' = z3' = 0, and z2 = z3 = 0 gives z2' = z3' = 0. The statement was
+	 * quantified over the underlying field, so it applies to Curve25519
+	 * itself and the quadratic twist of Curve25519. It was not proven in
+	 * Coq that prime-field arithmetic correctly simulates extension-field
+	 * arithmetic on prime-field values. The decoding of the byte array
+	 * representation of e was not considered.
+	 *
+	 * Specification of Montgomery curves in affine coordinates:
+	 * <https://github.com/mit-plv/fiat-crypto/blob/2456d821825521f7e03e65882cc3521795b0320f/src/Spec/MontgomeryCurve.v#L27>
+	 *
+	 * Proof that these form a group that is isomorphic to a Weierstrass
+	 * curve:
+	 * <https://github.com/mit-plv/fiat-crypto/blob/2456d821825521f7e03e65882cc3521795b0320f/src/Curves/Montgomery/AffineProofs.v#L35>
+	 *
+	 * Coq transcription and correctness proof of the loop
+	 * (where scalarbits=255):
+	 * <https://github.com/mit-plv/fiat-crypto/blob/2456d821825521f7e03e65882cc3521795b0320f/src/Curves/Montgomery/XZ.v#L118>
+	 * <https://github.com/mit-plv/fiat-crypto/blob/2456d821825521f7e03e65882cc3521795b0320f/src/Curves/Montgomery/XZProofs.v#L278>
+	 * preconditions: 0 <= e < 2^255 (not necessarily e < order),
+	 * fe_invert(0) = 0
+	 */
+	fe_frombytes(&x1, point);
+	fe_1(&x2);
+	fe_0(&z2);
+	fe_copy(&x3, &x1);
+	fe_1(&z3);
+
+	for (pos = 254; pos >= 0; --pos) {
+		fe tmp0, tmp1;
+		fe_loose tmp0l, tmp1l;
+		/* loop invariant as of right before the test, for the case
+		 * where x1 != 0:
+		 *   pos >= -1; if z2 = 0 then x2 is nonzero; if z3 = 0 then x3
+		 *   is nonzero
+		 *   let r := e >> (pos+1) in the following equalities of
+		 *   projective points:
+		 *   to_xz (r*P)     === if swap then (x3, z3) else (x2, z2)
+		 *   to_xz ((r+1)*P) === if swap then (x2, z2) else (x3, z3)
+		 *   x1 is the nonzero x coordinate of the nonzero
+		 *   point (r*P-(r+1)*P)
+		 */
+		unsigned b = 1 & (e[pos / 8] >> (pos & 7));
+		swap ^= b;
+		fe_cswap(&x2, &x3, swap);
+		fe_cswap(&z2, &z3, swap);
+		swap = b;
+		/* Coq transcription of ladderstep formula (called from
+		 * transcribed loop):
+		 * <https://github.com/mit-plv/fiat-crypto/blob/2456d821825521f7e03e65882cc3521795b0320f/src/Curves/Montgomery/XZ.v#L89>
+		 * <https://github.com/mit-plv/fiat-crypto/blob/2456d821825521f7e03e65882cc3521795b0320f/src/Curves/Montgomery/XZProofs.v#L131>
+		 * x1 != 0 <https://github.com/mit-plv/fiat-crypto/blob/2456d821825521f7e03e65882cc3521795b0320f/src/Curves/Montgomery/XZProofs.v#L217>
+		 * x1  = 0 <https://github.com/mit-plv/fiat-crypto/blob/2456d821825521f7e03e65882cc3521795b0320f/src/Curves/Montgomery/XZProofs.v#L147>
+		 */
+		fe_sub(&tmp0l, &x3, &z3);
+		fe_sub(&tmp1l, &x2, &z2);
+		fe_add(&x2l, &x2, &z2);
+		fe_add(&z2l, &x3, &z3);
+		fe_mul_tll(&z3, &tmp0l, &x2l);
+		fe_mul_tll(&z2, &z2l, &tmp1l);
+		fe_sq_tl(&tmp0, &tmp1l);
+		fe_sq_tl(&tmp1, &x2l);
+		fe_add(&x3l, &z3, &z2);
+		fe_sub(&z2l, &z3, &z2);
+		fe_mul_ttt(&x2, &tmp1, &tmp0);
+		fe_sub(&tmp1l, &tmp1, &tmp0);
+		fe_sq_tl(&z2, &z2l);
+		fe_mul121666(&z3, &tmp1l);
+		fe_sq_tl(&x3, &x3l);
+		fe_add(&tmp0l, &tmp0, &z3);
+		fe_mul_ttt(&z3, &x1, &z2);
+		fe_mul_tll(&z2, &tmp1l, &tmp0l);
+	}
+	/* here pos=-1, so r=e, so to_xz (e*P) === if swap then (x3, z3)
+	 * else (x2, z2)
+	 */
+	fe_cswap(&x2, &x3, swap);
+	fe_cswap(&z2, &z3, swap);
+
+	fe_invert(&z2, &z2);
+	fe_mul_ttt(&x2, &x2, &z2);
+	fe_tobytes(out, &x2);
+
+	memzero_explicit(&x1, sizeof(x1));
+	memzero_explicit(&x2, sizeof(x2));
+	memzero_explicit(&z2, sizeof(z2));
+	memzero_explicit(&x3, sizeof(x3));
+	memzero_explicit(&z3, sizeof(z3));
+	memzero_explicit(&x2l, sizeof(x2l));
+	memzero_explicit(&z2l, sizeof(z2l));
+	memzero_explicit(&x3l, sizeof(x3l));
+	memzero_explicit(&e, sizeof(e));
+}
diff --git a/src/crypto/curve25519-hacl64.h b/src/crypto/curve25519-hacl64.h
new file mode 100644
index 0000000..1fba1f5
--- /dev/null
+++ b/src/crypto/curve25519-hacl64.h
@@ -0,0 +1,784 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Copyright (C) 2016-2017 INRIA and Microsoft Corporation.
+ * Copyright (C) 2018-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * This is a machine-generated formally verified implementation of Curve25519
+ * ECDH from: <https://github.com/mitls/hacl-star>. Though originally machine
+ * generated, it has been tweaked to be suitable for use in the kernel. It is
+ * optimized for 64-bit machines that can efficiently work with 128-bit
+ * integer types.
+ */
+
+typedef __uint128_t u128;
+
+static __always_inline u64 u64_eq_mask(u64 a, u64 b)
+{
+	u64 x = a ^ b;
+	u64 minus_x = ~x + (u64)1U;
+	u64 x_or_minus_x = x | minus_x;
+	u64 xnx = x_or_minus_x >> (u32)63U;
+	u64 c = xnx - (u64)1U;
+	return c;
+}
+
+static __always_inline u64 u64_gte_mask(u64 a, u64 b)
+{
+	u64 x = a;
+	u64 y = b;
+	u64 x_xor_y = x ^ y;
+	u64 x_sub_y = x - y;
+	u64 x_sub_y_xor_y = x_sub_y ^ y;
+	u64 q = x_xor_y | x_sub_y_xor_y;
+	u64 x_xor_q = x ^ q;
+	u64 x_xor_q_ = x_xor_q >> (u32)63U;
+	u64 c = x_xor_q_ - (u64)1U;
+	return c;
+}
+
+static __always_inline void modulo_carry_top(u64 *b)
+{
+	u64 b4 = b[4];
+	u64 b0 = b[0];
+	u64 b4_ = b4 & 0x7ffffffffffffLLU;
+	u64 b0_ = b0 + 19 * (b4 >> 51);
+	b[4] = b4_;
+	b[0] = b0_;
+}
+
+static __always_inline void fproduct_copy_from_wide_(u64 *output, u128 *input)
+{
+	{
+		u128 xi = input[0];
+		output[0] = ((u64)(xi));
+	}
+	{
+		u128 xi = input[1];
+		output[1] = ((u64)(xi));
+	}
+	{
+		u128 xi = input[2];
+		output[2] = ((u64)(xi));
+	}
+	{
+		u128 xi = input[3];
+		output[3] = ((u64)(xi));
+	}
+	{
+		u128 xi = input[4];
+		output[4] = ((u64)(xi));
+	}
+}
+
+static __always_inline void
+fproduct_sum_scalar_multiplication_(u128 *output, u64 *input, u64 s)
+{
+	output[0] += (u128)input[0] * s;
+	output[1] += (u128)input[1] * s;
+	output[2] += (u128)input[2] * s;
+	output[3] += (u128)input[3] * s;
+	output[4] += (u128)input[4] * s;
+}
+
+static __always_inline void fproduct_carry_wide_(u128 *tmp)
+{
+	{
+		u32 ctr = 0;
+		u128 tctr = tmp[ctr];
+		u128 tctrp1 = tmp[ctr + 1];
+		u64 r0 = ((u64)(tctr)) & 0x7ffffffffffffLLU;
+		u128 c = ((tctr) >> (51));
+		tmp[ctr] = ((u128)(r0));
+		tmp[ctr + 1] = ((tctrp1) + (c));
+	}
+	{
+		u32 ctr = 1;
+		u128 tctr = tmp[ctr];
+		u128 tctrp1 = tmp[ctr + 1];
+		u64 r0 = ((u64)(tctr)) & 0x7ffffffffffffLLU;
+		u128 c = ((tctr) >> (51));
+		tmp[ctr] = ((u128)(r0));
+		tmp[ctr + 1] = ((tctrp1) + (c));
+	}
+
+	{
+		u32 ctr = 2;
+		u128 tctr = tmp[ctr];
+		u128 tctrp1 = tmp[ctr + 1];
+		u64 r0 = ((u64)(tctr)) & 0x7ffffffffffffLLU;
+		u128 c = ((tctr) >> (51));
+		tmp[ctr] = ((u128)(r0));
+		tmp[ctr + 1] = ((tctrp1) + (c));
+	}
+	{
+		u32 ctr = 3;
+		u128 tctr = tmp[ctr];
+		u128 tctrp1 = tmp[ctr + 1];
+		u64 r0 = ((u64)(tctr)) & 0x7ffffffffffffLLU;
+		u128 c = ((tctr) >> (51));
+		tmp[ctr] = ((u128)(r0));
+		tmp[ctr + 1] = ((tctrp1) + (c));
+	}
+}
+
+static __always_inline void fmul_shift_reduce(u64 *output)
+{
+	u64 tmp = output[4];
+	u64 b0;
+	{
+		u32 ctr = 5 - 0 - 1;
+		u64 z = output[ctr - 1];
+		output[ctr] = z;
+	}
+	{
+		u32 ctr = 5 - 1 - 1;
+		u64 z = output[ctr - 1];
+		output[ctr] = z;
+	}
+	{
+		u32 ctr = 5 - 2 - 1;
+		u64 z = output[ctr - 1];
+		output[ctr] = z;
+	}
+	{
+		u32 ctr = 5 - 3 - 1;
+		u64 z = output[ctr - 1];
+		output[ctr] = z;
+	}
+	output[0] = tmp;
+	b0 = output[0];
+	output[0] = 19 * b0;
+}
+
+static __always_inline void fmul_mul_shift_reduce_(u128 *output, u64 *input,
+						   u64 *input21)
+{
+	u32 i;
+	u64 input2i;
+	{
+		u64 input2i = input21[0];
+		fproduct_sum_scalar_multiplication_(output, input, input2i);
+		fmul_shift_reduce(input);
+	}
+	{
+		u64 input2i = input21[1];
+		fproduct_sum_scalar_multiplication_(output, input, input2i);
+		fmul_shift_reduce(input);
+	}
+	{
+		u64 input2i = input21[2];
+		fproduct_sum_scalar_multiplication_(output, input, input2i);
+		fmul_shift_reduce(input);
+	}
+	{
+		u64 input2i = input21[3];
+		fproduct_sum_scalar_multiplication_(output, input, input2i);
+		fmul_shift_reduce(input);
+	}
+	i = 4;
+	input2i = input21[i];
+	fproduct_sum_scalar_multiplication_(output, input, input2i);
+}
+
+static __always_inline void fmul_fmul(u64 *output, u64 *input, u64 *input21)
+{
+	u64 tmp[5] = { input[0], input[1], input[2], input[3], input[4] };
+	{
+		u128 b4;
+		u128 b0;
+		u128 b4_;
+		u128 b0_;
+		u64 i0;
+		u64 i1;
+		u64 i0_;
+		u64 i1_;
+		u128 t[5] = { 0 };
+		fmul_mul_shift_reduce_(t, tmp, input21);
+		fproduct_carry_wide_(t);
+		b4 = t[4];
+		b0 = t[0];
+		b4_ = ((b4) & (((u128)(0x7ffffffffffffLLU))));
+		b0_ = ((b0) + (((u128)(19) * (((u64)(((b4) >> (51))))))));
+		t[4] = b4_;
+		t[0] = b0_;
+		fproduct_copy_from_wide_(output, t);
+		i0 = output[0];
+		i1 = output[1];
+		i0_ = i0 & 0x7ffffffffffffLLU;
+		i1_ = i1 + (i0 >> 51);
+		output[0] = i0_;
+		output[1] = i1_;
+	}
+}
+
+static __always_inline void fsquare_fsquare__(u128 *tmp, u64 *output)
+{
+	u64 r0 = output[0];
+	u64 r1 = output[1];
+	u64 r2 = output[2];
+	u64 r3 = output[3];
+	u64 r4 = output[4];
+	u64 d0 = r0 * 2;
+	u64 d1 = r1 * 2;
+	u64 d2 = r2 * 2 * 19;
+	u64 d419 = r4 * 19;
+	u64 d4 = d419 * 2;
+	u128 s0 = ((((((u128)(r0) * (r0))) + (((u128)(d4) * (r1))))) +
+		   (((u128)(d2) * (r3))));
+	u128 s1 = ((((((u128)(d0) * (r1))) + (((u128)(d4) * (r2))))) +
+		   (((u128)(r3 * 19) * (r3))));
+	u128 s2 = ((((((u128)(d0) * (r2))) + (((u128)(r1) * (r1))))) +
+		   (((u128)(d4) * (r3))));
+	u128 s3 = ((((((u128)(d0) * (r3))) + (((u128)(d1) * (r2))))) +
+		   (((u128)(r4) * (d419))));
+	u128 s4 = ((((((u128)(d0) * (r4))) + (((u128)(d1) * (r3))))) +
+		   (((u128)(r2) * (r2))));
+	tmp[0] = s0;
+	tmp[1] = s1;
+	tmp[2] = s2;
+	tmp[3] = s3;
+	tmp[4] = s4;
+}
+
+static __always_inline void fsquare_fsquare_(u128 *tmp, u64 *output)
+{
+	u128 b4;
+	u128 b0;
+	u128 b4_;
+	u128 b0_;
+	u64 i0;
+	u64 i1;
+	u64 i0_;
+	u64 i1_;
+	fsquare_fsquare__(tmp, output);
+	fproduct_carry_wide_(tmp);
+	b4 = tmp[4];
+	b0 = tmp[0];
+	b4_ = ((b4) & (((u128)(0x7ffffffffffffLLU))));
+	b0_ = ((b0) + (((u128)(19) * (((u64)(((b4) >> (51))))))));
+	tmp[4] = b4_;
+	tmp[0] = b0_;
+	fproduct_copy_from_wide_(output, tmp);
+	i0 = output[0];
+	i1 = output[1];
+	i0_ = i0 & 0x7ffffffffffffLLU;
+	i1_ = i1 + (i0 >> 51);
+	output[0] = i0_;
+	output[1] = i1_;
+}
+
+static __always_inline void fsquare_fsquare_times_(u64 *output, u128 *tmp,
+						   u32 count1)
+{
+	u32 i;
+	fsquare_fsquare_(tmp, output);
+	for (i = 1; i < count1; ++i)
+		fsquare_fsquare_(tmp, output);
+}
+
+static __always_inline void fsquare_fsquare_times(u64 *output, u64 *input,
+						  u32 count1)
+{
+	u128 t[5];
+	memcpy(output, input, 5 * sizeof(*input));
+	fsquare_fsquare_times_(output, t, count1);
+}
+
+static __always_inline void fsquare_fsquare_times_inplace(u64 *output,
+							  u32 count1)
+{
+	u128 t[5];
+	fsquare_fsquare_times_(output, t, count1);
+}
+
+static __always_inline void crecip_crecip(u64 *out, u64 *z)
+{
+	u64 buf[20] = { 0 };
+	u64 *a0 = buf;
+	u64 *t00 = buf + 5;
+	u64 *b0 = buf + 10;
+	u64 *t01;
+	u64 *b1;
+	u64 *c0;
+	u64 *a;
+	u64 *t0;
+	u64 *b;
+	u64 *c;
+	fsquare_fsquare_times(a0, z, 1);
+	fsquare_fsquare_times(t00, a0, 2);
+	fmul_fmul(b0, t00, z);
+	fmul_fmul(a0, b0, a0);
+	fsquare_fsquare_times(t00, a0, 1);
+	fmul_fmul(b0, t00, b0);
+	fsquare_fsquare_times(t00, b0, 5);
+	t01 = buf + 5;
+	b1 = buf + 10;
+	c0 = buf + 15;
+	fmul_fmul(b1, t01, b1);
+	fsquare_fsquare_times(t01, b1, 10);
+	fmul_fmul(c0, t01, b1);
+	fsquare_fsquare_times(t01, c0, 20);
+	fmul_fmul(t01, t01, c0);
+	fsquare_fsquare_times_inplace(t01, 10);
+	fmul_fmul(b1, t01, b1);
+	fsquare_fsquare_times(t01, b1, 50);
+	a = buf;
+	t0 = buf + 5;
+	b = buf + 10;
+	c = buf + 15;
+	fmul_fmul(c, t0, b);
+	fsquare_fsquare_times(t0, c, 100);
+	fmul_fmul(t0, t0, c);
+	fsquare_fsquare_times_inplace(t0, 50);
+	fmul_fmul(t0, t0, b);
+	fsquare_fsquare_times_inplace(t0, 5);
+	fmul_fmul(out, t0, a);
+}
+
+static __always_inline void fsum(u64 *a, u64 *b)
+{
+	a[0] += b[0];
+	a[1] += b[1];
+	a[2] += b[2];
+	a[3] += b[3];
+	a[4] += b[4];
+}
+
+static __always_inline void fdifference(u64 *a, u64 *b)
+{
+	u64 tmp[5] = { 0 };
+	u64 b0;
+	u64 b1;
+	u64 b2;
+	u64 b3;
+	u64 b4;
+	memcpy(tmp, b, 5 * sizeof(*b));
+	b0 = tmp[0];
+	b1 = tmp[1];
+	b2 = tmp[2];
+	b3 = tmp[3];
+	b4 = tmp[4];
+	tmp[0] = b0 + 0x3fffffffffff68LLU;
+	tmp[1] = b1 + 0x3ffffffffffff8LLU;
+	tmp[2] = b2 + 0x3ffffffffffff8LLU;
+	tmp[3] = b3 + 0x3ffffffffffff8LLU;
+	tmp[4] = b4 + 0x3ffffffffffff8LLU;
+	{
+		u64 xi = a[0];
+		u64 yi = tmp[0];
+		a[0] = yi - xi;
+	}
+	{
+		u64 xi = a[1];
+		u64 yi = tmp[1];
+		a[1] = yi - xi;
+	}
+	{
+		u64 xi = a[2];
+		u64 yi = tmp[2];
+		a[2] = yi - xi;
+	}
+	{
+		u64 xi = a[3];
+		u64 yi = tmp[3];
+		a[3] = yi - xi;
+	}
+	{
+		u64 xi = a[4];
+		u64 yi = tmp[4];
+		a[4] = yi - xi;
+	}
+}
+
+static __always_inline void fscalar(u64 *output, u64 *b, u64 s)
+{
+	u128 tmp[5];
+	u128 b4;
+	u128 b0;
+	u128 b4_;
+	u128 b0_;
+	{
+		u64 xi = b[0];
+		tmp[0] = ((u128)(xi) * (s));
+	}
+	{
+		u64 xi = b[1];
+		tmp[1] = ((u128)(xi) * (s));
+	}
+	{
+		u64 xi = b[2];
+		tmp[2] = ((u128)(xi) * (s));
+	}
+	{
+		u64 xi = b[3];
+		tmp[3] = ((u128)(xi) * (s));
+	}
+	{
+		u64 xi = b[4];
+		tmp[4] = ((u128)(xi) * (s));
+	}
+	fproduct_carry_wide_(tmp);
+	b4 = tmp[4];
+	b0 = tmp[0];
+	b4_ = ((b4) & (((u128)(0x7ffffffffffffLLU))));
+	b0_ = ((b0) + (((u128)(19) * (((u64)(((b4) >> (51))))))));
+	tmp[4] = b4_;
+	tmp[0] = b0_;
+	fproduct_copy_from_wide_(output, tmp);
+}
+
+static __always_inline void fmul(u64 *output, u64 *a, u64 *b)
+{
+	fmul_fmul(output, a, b);
+}
+
+static __always_inline void crecip(u64 *output, u64 *input)
+{
+	crecip_crecip(output, input);
+}
+
+static __always_inline void point_swap_conditional_step(u64 *a, u64 *b,
+							u64 swap1, u32 ctr)
+{
+	u32 i = ctr - 1;
+	u64 ai = a[i];
+	u64 bi = b[i];
+	u64 x = swap1 & (ai ^ bi);
+	u64 ai1 = ai ^ x;
+	u64 bi1 = bi ^ x;
+	a[i] = ai1;
+	b[i] = bi1;
+}
+
+static __always_inline void point_swap_conditional5(u64 *a, u64 *b, u64 swap1)
+{
+	point_swap_conditional_step(a, b, swap1, 5);
+	point_swap_conditional_step(a, b, swap1, 4);
+	point_swap_conditional_step(a, b, swap1, 3);
+	point_swap_conditional_step(a, b, swap1, 2);
+	point_swap_conditional_step(a, b, swap1, 1);
+}
+
+static __always_inline void point_swap_conditional(u64 *a, u64 *b, u64 iswap)
+{
+	u64 swap1 = 0 - iswap;
+	point_swap_conditional5(a, b, swap1);
+	point_swap_conditional5(a + 5, b + 5, swap1);
+}
+
+static __always_inline void point_copy(u64 *output, u64 *input)
+{
+	memcpy(output, input, 5 * sizeof(*input));
+	memcpy(output + 5, input + 5, 5 * sizeof(*input));
+}
+
+static __always_inline void addanddouble_fmonty(u64 *pp, u64 *ppq, u64 *p,
+						u64 *pq, u64 *qmqp)
+{
+	u64 *qx = qmqp;
+	u64 *x2 = pp;
+	u64 *z2 = pp + 5;
+	u64 *x3 = ppq;
+	u64 *z3 = ppq + 5;
+	u64 *x = p;
+	u64 *z = p + 5;
+	u64 *xprime = pq;
+	u64 *zprime = pq + 5;
+	u64 buf[40] = { 0 };
+	u64 *origx = buf;
+	u64 *origxprime0 = buf + 5;
+	u64 *xxprime0;
+	u64 *zzprime0;
+	u64 *origxprime;
+	xxprime0 = buf + 25;
+	zzprime0 = buf + 30;
+	memcpy(origx, x, 5 * sizeof(*x));
+	fsum(x, z);
+	fdifference(z, origx);
+	memcpy(origxprime0, xprime, 5 * sizeof(*xprime));
+	fsum(xprime, zprime);
+	fdifference(zprime, origxprime0);
+	fmul(xxprime0, xprime, z);
+	fmul(zzprime0, x, zprime);
+	origxprime = buf + 5;
+	{
+		u64 *xx0;
+		u64 *zz0;
+		u64 *xxprime;
+		u64 *zzprime;
+		u64 *zzzprime;
+		xx0 = buf + 15;
+		zz0 = buf + 20;
+		xxprime = buf + 25;
+		zzprime = buf + 30;
+		zzzprime = buf + 35;
+		memcpy(origxprime, xxprime, 5 * sizeof(*xxprime));
+		fsum(xxprime, zzprime);
+		fdifference(zzprime, origxprime);
+		fsquare_fsquare_times(x3, xxprime, 1);
+		fsquare_fsquare_times(zzzprime, zzprime, 1);
+		fmul(z3, zzzprime, qx);
+		fsquare_fsquare_times(xx0, x, 1);
+		fsquare_fsquare_times(zz0, z, 1);
+		{
+			u64 *zzz;
+			u64 *xx;
+			u64 *zz;
+			u64 scalar;
+			zzz = buf + 10;
+			xx = buf + 15;
+			zz = buf + 20;
+			fmul(x2, xx, zz);
+			fdifference(zz, xx);
+			scalar = 121665;
+			fscalar(zzz, zz, scalar);
+			fsum(zzz, xx);
+			fmul(z2, zzz, zz);
+		}
+	}
+}
+
+static __always_inline void
+ladder_smallloop_cmult_small_loop_step(u64 *nq, u64 *nqpq, u64 *nq2, u64 *nqpq2,
+				       u64 *q, u8 byt)
+{
+	u64 bit0 = (u64)(byt >> 7);
+	u64 bit;
+	point_swap_conditional(nq, nqpq, bit0);
+	addanddouble_fmonty(nq2, nqpq2, nq, nqpq, q);
+	bit = (u64)(byt >> 7);
+	point_swap_conditional(nq2, nqpq2, bit);
+}
+
+static __always_inline void
+ladder_smallloop_cmult_small_loop_double_step(u64 *nq, u64 *nqpq, u64 *nq2,
+					      u64 *nqpq2, u64 *q, u8 byt)
+{
+	u8 byt1;
+	ladder_smallloop_cmult_small_loop_step(nq, nqpq, nq2, nqpq2, q, byt);
+	byt1 = byt << 1;
+	ladder_smallloop_cmult_small_loop_step(nq2, nqpq2, nq, nqpq, q, byt1);
+}
+
+static __always_inline void
+ladder_smallloop_cmult_small_loop(u64 *nq, u64 *nqpq, u64 *nq2, u64 *nqpq2,
+				  u64 *q, u8 byt, u32 i)
+{
+	while (i--) {
+		ladder_smallloop_cmult_small_loop_double_step(nq, nqpq, nq2,
+							      nqpq2, q, byt);
+		byt <<= 2;
+	}
+}
+
+static __always_inline void ladder_bigloop_cmult_big_loop(u8 *n1, u64 *nq,
+							  u64 *nqpq, u64 *nq2,
+							  u64 *nqpq2, u64 *q,
+							  u32 i)
+{
+	while (i--) {
+		u8 byte = n1[i];
+		ladder_smallloop_cmult_small_loop(nq, nqpq, nq2, nqpq2, q,
+						  byte, 4);
+	}
+}
+
+static void ladder_cmult(u64 *result, u8 *n1, u64 *q)
+{
+	u64 point_buf[40] = { 0 };
+	u64 *nq = point_buf;
+	u64 *nqpq = point_buf + 10;
+	u64 *nq2 = point_buf + 20;
+	u64 *nqpq2 = point_buf + 30;
+	point_copy(nqpq, q);
+	nq[0] = 1;
+	ladder_bigloop_cmult_big_loop(n1, nq, nqpq, nq2, nqpq2, q, 32);
+	point_copy(result, nq);
+}
+
+static __always_inline void format_fexpand(u64 *output, const u8 *input)
+{
+	const u8 *x00 = input + 6;
+	const u8 *x01 = input + 12;
+	const u8 *x02 = input + 19;
+	const u8 *x0 = input + 24;
+	u64 i0, i1, i2, i3, i4, output0, output1, output2, output3, output4;
+	i0 = get_unaligned_le64(input);
+	i1 = get_unaligned_le64(x00);
+	i2 = get_unaligned_le64(x01);
+	i3 = get_unaligned_le64(x02);
+	i4 = get_unaligned_le64(x0);
+	output0 = i0 & 0x7ffffffffffffLLU;
+	output1 = i1 >> 3 & 0x7ffffffffffffLLU;
+	output2 = i2 >> 6 & 0x7ffffffffffffLLU;
+	output3 = i3 >> 1 & 0x7ffffffffffffLLU;
+	output4 = i4 >> 12 & 0x7ffffffffffffLLU;
+	output[0] = output0;
+	output[1] = output1;
+	output[2] = output2;
+	output[3] = output3;
+	output[4] = output4;
+}
+
+static __always_inline void format_fcontract_first_carry_pass(u64 *input)
+{
+	u64 t0 = input[0];
+	u64 t1 = input[1];
+	u64 t2 = input[2];
+	u64 t3 = input[3];
+	u64 t4 = input[4];
+	u64 t1_ = t1 + (t0 >> 51);
+	u64 t0_ = t0 & 0x7ffffffffffffLLU;
+	u64 t2_ = t2 + (t1_ >> 51);
+	u64 t1__ = t1_ & 0x7ffffffffffffLLU;
+	u64 t3_ = t3 + (t2_ >> 51);
+	u64 t2__ = t2_ & 0x7ffffffffffffLLU;
+	u64 t4_ = t4 + (t3_ >> 51);
+	u64 t3__ = t3_ & 0x7ffffffffffffLLU;
+	input[0] = t0_;
+	input[1] = t1__;
+	input[2] = t2__;
+	input[3] = t3__;
+	input[4] = t4_;
+}
+
+static __always_inline void format_fcontract_first_carry_full(u64 *input)
+{
+	format_fcontract_first_carry_pass(input);
+	modulo_carry_top(input);
+}
+
+static __always_inline void format_fcontract_second_carry_pass(u64 *input)
+{
+	u64 t0 = input[0];
+	u64 t1 = input[1];
+	u64 t2 = input[2];
+	u64 t3 = input[3];
+	u64 t4 = input[4];
+	u64 t1_ = t1 + (t0 >> 51);
+	u64 t0_ = t0 & 0x7ffffffffffffLLU;
+	u64 t2_ = t2 + (t1_ >> 51);
+	u64 t1__ = t1_ & 0x7ffffffffffffLLU;
+	u64 t3_ = t3 + (t2_ >> 51);
+	u64 t2__ = t2_ & 0x7ffffffffffffLLU;
+	u64 t4_ = t4 + (t3_ >> 51);
+	u64 t3__ = t3_ & 0x7ffffffffffffLLU;
+	input[0] = t0_;
+	input[1] = t1__;
+	input[2] = t2__;
+	input[3] = t3__;
+	input[4] = t4_;
+}
+
+static __always_inline void format_fcontract_second_carry_full(u64 *input)
+{
+	u64 i0;
+	u64 i1;
+	u64 i0_;
+	u64 i1_;
+	format_fcontract_second_carry_pass(input);
+	modulo_carry_top(input);
+	i0 = input[0];
+	i1 = input[1];
+	i0_ = i0 & 0x7ffffffffffffLLU;
+	i1_ = i1 + (i0 >> 51);
+	input[0] = i0_;
+	input[1] = i1_;
+}
+
+static __always_inline void format_fcontract_trim(u64 *input)
+{
+	u64 a0 = input[0];
+	u64 a1 = input[1];
+	u64 a2 = input[2];
+	u64 a3 = input[3];
+	u64 a4 = input[4];
+	u64 mask0 = u64_gte_mask(a0, 0x7ffffffffffedLLU);
+	u64 mask1 = u64_eq_mask(a1, 0x7ffffffffffffLLU);
+	u64 mask2 = u64_eq_mask(a2, 0x7ffffffffffffLLU);
+	u64 mask3 = u64_eq_mask(a3, 0x7ffffffffffffLLU);
+	u64 mask4 = u64_eq_mask(a4, 0x7ffffffffffffLLU);
+	u64 mask = (((mask0 & mask1) & mask2) & mask3) & mask4;
+	u64 a0_ = a0 - (0x7ffffffffffedLLU & mask);
+	u64 a1_ = a1 - (0x7ffffffffffffLLU & mask);
+	u64 a2_ = a2 - (0x7ffffffffffffLLU & mask);
+	u64 a3_ = a3 - (0x7ffffffffffffLLU & mask);
+	u64 a4_ = a4 - (0x7ffffffffffffLLU & mask);
+	input[0] = a0_;
+	input[1] = a1_;
+	input[2] = a2_;
+	input[3] = a3_;
+	input[4] = a4_;
+}
+
+static __always_inline void format_fcontract_store(u8 *output, u64 *input)
+{
+	u64 t0 = input[0];
+	u64 t1 = input[1];
+	u64 t2 = input[2];
+	u64 t3 = input[3];
+	u64 t4 = input[4];
+	u64 o0 = t1 << 51 | t0;
+	u64 o1 = t2 << 38 | t1 >> 13;
+	u64 o2 = t3 << 25 | t2 >> 26;
+	u64 o3 = t4 << 12 | t3 >> 39;
+	u8 *b0 = output;
+	u8 *b1 = output + 8;
+	u8 *b2 = output + 16;
+	u8 *b3 = output + 24;
+	put_unaligned_le64(o0, b0);
+	put_unaligned_le64(o1, b1);
+	put_unaligned_le64(o2, b2);
+	put_unaligned_le64(o3, b3);
+}
+
+static __always_inline void format_fcontract(u8 *output, u64 *input)
+{
+	format_fcontract_first_carry_full(input);
+	format_fcontract_second_carry_full(input);
+	format_fcontract_trim(input);
+	format_fcontract_store(output, input);
+}
+
+static __always_inline void format_scalar_of_point(u8 *scalar, u64 *point)
+{
+	u64 *x = point;
+	u64 *z = point + 5;
+	u64 buf[10] __aligned(32) = { 0 };
+	u64 *zmone = buf;
+	u64 *sc = buf + 5;
+	crecip(zmone, z);
+	fmul(sc, x, zmone);
+	format_fcontract(scalar, sc);
+}
+
+static void curve25519_generic(u8 mypublic[CURVE25519_KEY_SIZE],
+			       const u8 secret[CURVE25519_KEY_SIZE],
+			       const u8 basepoint[CURVE25519_KEY_SIZE])
+{
+	u64 buf0[10] __aligned(32) = { 0 };
+	u64 *x0 = buf0;
+	u64 *z = buf0 + 5;
+	u64 *q;
+	format_fexpand(x0, basepoint);
+	z[0] = 1;
+	q = buf0;
+	{
+		u8 e[32] __aligned(32) = { 0 };
+		u8 *scalar;
+		memcpy(e, secret, 32);
+		curve25519_clamp_secret(e);
+		scalar = e;
+		{
+			u64 buf[15] = { 0 };
+			u64 *nq = buf;
+			u64 *x = nq;
+			x[0] = 1;
+			ladder_cmult(nq, scalar, q);
+			format_scalar_of_point(mypublic, nq);
+			memzero_explicit(buf, sizeof(buf));
+		}
+		memzero_explicit(e, sizeof(e));
+	}
+	memzero_explicit(buf0, sizeof(buf0));
+}
diff --git a/src/crypto/curve25519.c b/src/crypto/curve25519.c
new file mode 100644
index 0000000..7121d1e
--- /dev/null
+++ b/src/crypto/curve25519.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Copyright (C) 2018-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#include "curve25519.h"
+
+#include <stdint.h>
+#include <string.h>
+
+#ifndef __BYTE_ORDER__
+#include <sys/param.h>
+#if !defined(BYTE_ORDER) || !defined(BIG_ENDIAN) || !defined(LITTLE_ENDIAN)
+#error "Unable to determine endianness."
+#endif
+#define __BYTE_ORDER__ BYTE_ORDER
+#define __ORDER_BIG_ENDIAN__ BIG_ENDIAN
+#define __ORDER_LITTLE_ENDIAN__ LITTLE_ENDIAN
+#endif
+
+#ifdef __linux__
+#include <linux/types.h>
+typedef __u64 u64;
+typedef __u32 u32;
+typedef __u8 u8;
+typedef __s64 s64;
+#else
+typedef uint64_t u64, __le64;
+typedef uint32_t u32, __le32;
+typedef uint8_t u8;
+typedef int64_t s64;
+#endif
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#define le64_to_cpup(a) __builtin_bswap64(*(a))
+#define le32_to_cpup(a) __builtin_bswap32(*(a))
+#define cpu_to_le64(a) __builtin_bswap64(a)
+#else
+#define le64_to_cpup(a) (*(a))
+#define le32_to_cpup(a) (*(a))
+#define cpu_to_le64(a) (a)
+#endif
+#ifndef __unused
+#define __unused  __attribute__((unused))
+#endif
+#ifndef __always_inline
+#define __always_inline __inline __attribute__((__always_inline__))
+#endif
+#ifndef noinline
+#define noinline __attribute__((noinline))
+#endif
+#ifndef __aligned
+#define __aligned(x) __attribute__((aligned(x)))
+#endif
+#ifndef __force
+#define __force
+#endif
+
+static __always_inline __unused __le32 get_unaligned_le32(const u8 *a)
+{
+	__le32 l;
+	__builtin_memcpy(&l, a, sizeof(l));
+	return le32_to_cpup(&l);
+}
+static __always_inline __unused __le64 get_unaligned_le64(const u8 *a)
+{
+	__le64 l;
+	__builtin_memcpy(&l, a, sizeof(l));
+	return le64_to_cpup(&l);
+}
+static __always_inline __unused void put_unaligned_le64(u64 s, u8 *d)
+{
+	__le64 l = cpu_to_le64(s);
+	__builtin_memcpy(d, &l, sizeof(l));
+}
+
+static noinline void memzero_explicit(void *s, size_t count)
+{
+	memset(s, 0, count);
+	asm volatile("": :"r"(s) : "memory");
+}
+
+#ifdef __SIZEOF_INT128__
+#include "curve25519-hacl64.h"
+#else
+#include "curve25519-fiat32.h"
+#endif
+
+void curve25519_generate_public(uint8_t pub[static CURVE25519_KEY_SIZE], const uint8_t secret[static CURVE25519_KEY_SIZE])
+{
+	static const uint8_t basepoint[CURVE25519_KEY_SIZE] __aligned(sizeof(uintptr_t)) = { 9 };
+
+	curve25519(pub, secret, basepoint);
+}
+
+void curve25519(uint8_t mypublic[static CURVE25519_KEY_SIZE], const uint8_t secret[static CURVE25519_KEY_SIZE], const uint8_t basepoint[static CURVE25519_KEY_SIZE])
+{
+	curve25519_generic(mypublic, secret, basepoint);
+}
diff --git a/src/crypto/curve25519.h b/src/crypto/curve25519.h
new file mode 100644
index 0000000..b05432f
--- /dev/null
+++ b/src/crypto/curve25519.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
+/*
+ * Copyright (C) 2015-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#ifndef CURVE25519_H
+#define CURVE25519_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+enum curve25519_lengths {
+	CURVE25519_KEY_SIZE = 32
+};
+
+void curve25519(uint8_t mypublic[static CURVE25519_KEY_SIZE], const uint8_t secret[static CURVE25519_KEY_SIZE], const uint8_t basepoint[static CURVE25519_KEY_SIZE]);
+void curve25519_generate_public(uint8_t pub[static CURVE25519_KEY_SIZE], const uint8_t secret[static CURVE25519_KEY_SIZE]);
+static inline void curve25519_clamp_secret(uint8_t secret[static CURVE25519_KEY_SIZE])
+{
+	secret[0] &= 248;
+	secret[31] = (secret[31] & 127) | 64;
+}
+
+#endif
diff --git a/src/crypto/encoding.c b/src/crypto/encoding.c
new file mode 100644
index 0000000..9b2cda5
--- /dev/null
+++ b/src/crypto/encoding.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Copyright (C) 2015-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * This is a specialized constant-time base64/hex implementation that resists side-channel attacks.
+ */
+
+#include <string.h>
+#include "encoding.h"
+
+static inline void encode_base64(char dest[static 4], const uint8_t src[static 3])
+{
+	const uint8_t input[] = { (src[0] >> 2) & 63, ((src[0] << 4) | (src[1] >> 4)) & 63, ((src[1] << 2) | (src[2] >> 6)) & 63, src[2] & 63 };
+
+	for (unsigned int i = 0; i < 4; ++i)
+		dest[i] = input[i] + 'A'
+			  + (((25 - input[i]) >> 8) & 6)
+			  - (((51 - input[i]) >> 8) & 75)
+			  - (((61 - input[i]) >> 8) & 15)
+			  + (((62 - input[i]) >> 8) & 3);
+
+}
+
+void key_to_base64(char base64[static WG_KEY_LEN_BASE64], const uint8_t key[static WG_KEY_LEN])
+{
+	unsigned int i;
+
+	for (i = 0; i < WG_KEY_LEN / 3; ++i)
+		encode_base64(&base64[i * 4], &key[i * 3]);
+	encode_base64(&base64[i * 4], (const uint8_t[]){ key[i * 3 + 0], key[i * 3 + 1], 0 });
+	base64[WG_KEY_LEN_BASE64 - 2] = '=';
+	base64[WG_KEY_LEN_BASE64 - 1] = '\0';
+}
+
+static inline int decode_base64(const char src[static 4])
+{
+	int val = 0;
+
+	for (unsigned int i = 0; i < 4; ++i)
+		val |= (-1
+			    + ((((('A' - 1) - src[i]) & (src[i] - ('Z' + 1))) >> 8) & (src[i] - 64))
+			    + ((((('a' - 1) - src[i]) & (src[i] - ('z' + 1))) >> 8) & (src[i] - 70))
+			    + ((((('0' - 1) - src[i]) & (src[i] - ('9' + 1))) >> 8) & (src[i] + 5))
+			    + ((((('+' - 1) - src[i]) & (src[i] - ('+' + 1))) >> 8) & 63)
+			    + ((((('/' - 1) - src[i]) & (src[i] - ('/' + 1))) >> 8) & 64)
+			) << (18 - 6 * i);
+	return val;
+}
+
+bool key_from_base64(uint8_t key[static WG_KEY_LEN], const char *base64)
+{
+	unsigned int i;
+	volatile uint8_t ret = 0;
+	int val;
+
+	if (strlen(base64) != WG_KEY_LEN_BASE64 - 1 || base64[WG_KEY_LEN_BASE64 - 2] != '=')
+		return false;
+
+	for (i = 0; i < WG_KEY_LEN / 3; ++i) {
+		val = decode_base64(&base64[i * 4]);
+		ret |= (uint32_t)val >> 31;
+		key[i * 3 + 0] = (val >> 16) & 0xff;
+		key[i * 3 + 1] = (val >> 8) & 0xff;
+		key[i * 3 + 2] = val & 0xff;
+	}
+	val = decode_base64((const char[]){ base64[i * 4 + 0], base64[i * 4 + 1], base64[i * 4 + 2], 'A' });
+	ret |= ((uint32_t)val >> 31) | (val & 0xff);
+	key[i * 3 + 0] = (val >> 16) & 0xff;
+	key[i * 3 + 1] = (val >> 8) & 0xff;
+
+	return 1 & ((ret - 1) >> 8);
+}
+
+void key_to_hex(char hex[static WG_KEY_LEN_HEX], const uint8_t key[static WG_KEY_LEN])
+{
+	unsigned int i;
+
+	for (i = 0; i < WG_KEY_LEN; ++i) {
+		hex[i * 2] = 87U + (key[i] >> 4) + ((((key[i] >> 4) - 10U) >> 8) & ~38U);
+		hex[i * 2 + 1] = 87U + (key[i] & 0xf) + ((((key[i] & 0xf) - 10U) >> 8) & ~38U);
+	}
+	hex[i * 2] = '\0';
+}
+
+bool key_from_hex(uint8_t key[static WG_KEY_LEN], const char *hex)
+{
+	uint8_t c, c_acc, c_alpha0, c_alpha, c_num0, c_num, c_val;
+	volatile uint8_t ret = 0;
+
+	if (strlen(hex) != WG_KEY_LEN_HEX - 1)
+		return false;
+
+	for (unsigned int i = 0; i < WG_KEY_LEN_HEX - 1; i += 2) {
+		c = (uint8_t)hex[i];
+		c_num = c ^ 48U;
+		c_num0 = (c_num - 10U) >> 8;
+		c_alpha = (c & ~32U) - 55U;
+		c_alpha0 = ((c_alpha - 10U) ^ (c_alpha - 16U)) >> 8;
+		ret |= ((c_num0 | c_alpha0) - 1) >> 8;
+		c_val = (c_num0 & c_num) | (c_alpha0 & c_alpha);
+		c_acc = c_val * 16U;
+
+		c = (uint8_t)hex[i + 1];
+		c_num = c ^ 48U;
+		c_num0 = (c_num - 10U) >> 8;
+		c_alpha = (c & ~32U) - 55U;
+		c_alpha0 = ((c_alpha - 10U) ^ (c_alpha - 16U)) >> 8;
+		ret |= ((c_num0 | c_alpha0) - 1) >> 8;
+		c_val = (c_num0 & c_num) | (c_alpha0 & c_alpha);
+		key[i / 2] = c_acc | c_val;
+	}
+
+	return 1 & ((ret - 1) >> 8);
+}
+
+bool key_is_zero(const uint8_t key[static WG_KEY_LEN])
+{
+	volatile uint8_t acc = 0;
+
+	for (unsigned int i = 0; i < WG_KEY_LEN; ++i) {
+		acc |= key[i];
+		asm volatile("" : "=r"(acc) : "0"(acc));
+	}
+	return 1 & ((acc - 1) >> 8);
+}
diff --git a/src/crypto/encoding.h b/src/crypto/encoding.h
new file mode 100644
index 0000000..bc54049
--- /dev/null
+++ b/src/crypto/encoding.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
+/*
+ * Copyright (C) 2015-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#ifndef ENCODING_H
+#define ENCODING_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#ifndef WG_KEY_LEN
+#define WG_KEY_LEN 32
+#endif
+
+#define WG_KEY_LEN_BASE64 ((((WG_KEY_LEN) + 2) / 3) * 4 + 1)
+#define WG_KEY_LEN_HEX (WG_KEY_LEN * 2 + 1)
+
+void key_to_base64(char base64[static WG_KEY_LEN_BASE64], const uint8_t key[static WG_KEY_LEN]);
+bool key_from_base64(uint8_t key[static WG_KEY_LEN], const char *base64);
+
+void key_to_hex(char hex[static WG_KEY_LEN_HEX], const uint8_t key[static WG_KEY_LEN]);
+bool key_from_hex(uint8_t key[static WG_KEY_LEN], const char *hex);
+
+bool key_is_zero(const uint8_t key[static WG_KEY_LEN]);
+
+#endif
diff --git a/src/crypto/halfsiphash.c b/src/crypto/halfsiphash.c
new file mode 100644
index 0000000..455c27c
--- /dev/null
+++ b/src/crypto/halfsiphash.c
@@ -0,0 +1,166 @@
+
+/*
+   SipHash reference C implementation
+
+   Copyright (c) 2016 Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
+
+   To the extent possible under law, the author(s) have dedicated all copyright
+   and related and neighboring rights to this software to the public domain
+   worldwide. This software is distributed without any warranty.
+
+   You should have received a copy of the CC0 Public Domain Dedication along
+   with
+   this software. If not, see
+   <http://creativecommons.org/publicdomain/zero/1.0/>.
+ */
+#include "halfsiphash.h"
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+
+/* default: SipHash-2-4 */
+#ifndef cROUNDS
+#define cROUNDS 2
+#endif
+#ifndef dROUNDS
+#define dROUNDS 4
+#endif
+
+#define ROTL(x, b) (uint32_t)(((x) << (b)) | ((x) >> (32 - (b))))
+
+#define U32TO8_LE(p, v)                                                        \
+    (p)[0] = (uint8_t)((v));                                                   \
+    (p)[1] = (uint8_t)((v) >> 8);                                              \
+    (p)[2] = (uint8_t)((v) >> 16);                                             \
+    (p)[3] = (uint8_t)((v) >> 24);
+
+#define U8TO32_LE(p)                                                           \
+    (((uint32_t)((p)[0])) | ((uint32_t)((p)[1]) << 8) |                        \
+     ((uint32_t)((p)[2]) << 16) | ((uint32_t)((p)[3]) << 24))
+
+#define SIPROUND                                                               \
+    do {                                                                       \
+        v0 += v1;                                                              \
+        v1 = ROTL(v1, 5);                                                      \
+        v1 ^= v0;                                                              \
+        v0 = ROTL(v0, 16);                                                     \
+        v2 += v3;                                                              \
+        v3 = ROTL(v3, 8);                                                      \
+        v3 ^= v2;                                                              \
+        v0 += v3;                                                              \
+        v3 = ROTL(v3, 7);                                                      \
+        v3 ^= v0;                                                              \
+        v2 += v1;                                                              \
+        v1 = ROTL(v1, 13);                                                     \
+        v1 ^= v2;                                                              \
+        v2 = ROTL(v2, 16);                                                     \
+    } while (0)
+
+
+#ifdef DEBUG_SIPHASH
+#include <stdio.h>
+
+#define TRACE                                                                  \
+    do {                                                                       \
+        printf("(%3zu) v0 %08" PRIx32 "\n", inlen, v0);                        \
+        printf("(%3zu) v1 %08" PRIx32 "\n", inlen, v1);                        \
+        printf("(%3zu) v2 %08" PRIx32 "\n", inlen, v2);                        \
+        printf("(%3zu) v3 %08" PRIx32 "\n", inlen, v3);                        \
+    } while (0)
+#else
+#define TRACE
+#endif
+
+/*
+    Computes a SipHash value
+    *in: pointer to input data (read-only)
+    inlen: input data length in bytes (any size_t value)
+    *k: pointer to the key data (read-only), must be 8 bytes 
+    *out: pointer to output data (write-only), outlen bytes must be allocated
+    outlen: length of the output in bytes, must be 4 or 8
+*/
+int halfsiphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
+                const size_t outlen) {
+
+    const unsigned char *ni = (const unsigned char *)in;
+    const unsigned char *kk = (const unsigned char *)k;
+
+    assert((outlen == 4) || (outlen == 8));
+    uint32_t v0 = 0;
+    uint32_t v1 = 0;
+    uint32_t v2 = UINT32_C(0x6c796765);
+    uint32_t v3 = UINT32_C(0x74656462);
+    uint32_t k0 = U8TO32_LE(kk);
+    uint32_t k1 = U8TO32_LE(kk + 4);
+    uint32_t m;
+    int i;
+    const unsigned char *end = ni + inlen - (inlen % sizeof(uint32_t));
+    const int left = inlen & 3;
+    uint32_t b = ((uint32_t)inlen) << 24;
+    v3 ^= k1;
+    v2 ^= k0;
+    v1 ^= k1;
+    v0 ^= k0;
+
+    if (outlen == 8)
+        v1 ^= 0xee;
+
+    for (; ni != end; ni += 4) {
+        m = U8TO32_LE(ni);
+        v3 ^= m;
+
+        TRACE;
+        for (i = 0; i < cROUNDS; ++i)
+            SIPROUND;
+
+        v0 ^= m;
+    }
+
+    switch (left) {
+    case 3:
+        b |= ((uint32_t)ni[2]) << 16;
+        /* FALLTHRU */
+    case 2:
+        b |= ((uint32_t)ni[1]) << 8;
+        /* FALLTHRU */
+    case 1:
+        b |= ((uint32_t)ni[0]);
+        break;
+    case 0:
+        break;
+    }
+
+    v3 ^= b;
+
+    TRACE;
+    for (i = 0; i < cROUNDS; ++i)
+        SIPROUND;
+
+    v0 ^= b;
+
+    if (outlen == 8)
+        v2 ^= 0xee;
+    else
+        v2 ^= 0xff;
+
+    TRACE;
+    for (i = 0; i < dROUNDS; ++i)
+        SIPROUND;
+
+    b = v1 ^ v3;
+    U32TO8_LE(out, b);
+
+    if (outlen == 4)
+        return 0;
+
+    v1 ^= 0xdd;
+
+    TRACE;
+    for (i = 0; i < dROUNDS; ++i)
+        SIPROUND;
+
+    b = v1 ^ v3;
+    U32TO8_LE(out + 4, b);
+
+    return 0;
+}
diff --git a/src/crypto/halfsiphash.h b/src/crypto/halfsiphash.h
new file mode 100644
index 0000000..a1af8cd
--- /dev/null
+++ b/src/crypto/halfsiphash.h
@@ -0,0 +1,22 @@
+/*
+   SipHash reference C implementation
+
+   Copyright (c) 2012-2021 Jean-Philippe Aumasson
+   <jeanphilippe.aumasson@gmail.com>
+   Copyright (c) 2012-2014 Daniel J. Bernstein <djb@cr.yp.to>
+
+   To the extent possible under law, the author(s) have dedicated all copyright
+   and related and neighboring rights to this software to the public domain
+   worldwide. This software is distributed without any warranty.
+
+   You should have received a copy of the CC0 Public Domain Dedication along
+   with
+   this software. If not, see
+   <http://creativecommons.org/publicdomain/zero/1.0/>.
+ */
+
+#include <inttypes.h>
+#include <string.h>
+
+int halfsiphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
+                const size_t outlen);
diff --git a/src/crypto/pubkey.c b/src/crypto/pubkey.c
new file mode 100644
index 0000000..1224b07
--- /dev/null
+++ b/src/crypto/pubkey.c
@@ -0,0 +1,27 @@
+#include "curve25519.h"
+#include "encoding.h"
+
+int wg_pubkey_base64(char const * privkey, char * base64) {
+
+	uint8_t key[WG_KEY_LEN] __attribute((aligned(sizeof(uintptr_t))));
+
+	int i;
+	for(i = 0; privkey[i] && i < WG_KEY_LEN_BASE64 - 1; i++)
+		base64[i] = privkey[i];
+
+	base64[WG_KEY_LEN_BASE64 - 1] = '\0';
+
+	if(i != WG_KEY_LEN_BASE64 - 1 || privkey[i]) {
+		return 1;
+	}
+
+	if(!key_from_base64(key, base64)) {
+		return 1;
+	}
+
+	curve25519_generate_public(key, key);
+
+	key_to_base64(base64, key);
+
+	return 0;
+}
diff --git a/src/crypto/pubkey.hpp b/src/crypto/pubkey.hpp
new file mode 100644
index 0000000..8596431
--- /dev/null
+++ b/src/crypto/pubkey.hpp
@@ -0,0 +1,22 @@
+extern "C" {
+
+#ifndef WG_KEY_LEN
+#define WG_KEY_LEN 32
+#endif
+
+#define WG_KEY_LEN_BASE64 ((((WG_KEY_LEN) + 2) / 3) * 4 + 1)
+
+/*
+ * wg_pubkey_base64 is a C++-compatible wrapper for the curve25519 public-key
+ * derivation routines used natively in `wg(8)`
+ *
+ * PRIVKEY: a c-style string containing the base64-encoded private key
+ * BASE64:  a c-style string of capacity WG_KEY_LEN_BASE64 containing the
+ * encoded public key
+ *
+ * returns: 0 on success
+ *          > 0 when an error occurs (due to improper key formatting)
+ */
+int wg_pubkey_base64(char const * privkey, char * base64);
+
+}
diff --git a/src/wg2nd.cpp b/src/wg2nd.cpp
index c53df04..1491ce4 100644
--- a/src/wg2nd.cpp
+++ b/src/wg2nd.cpp
@@ -5,71 +5,45 @@
 #include <random>
 #include <regex>
 
-#include <argon2.h>
 #include <string_view>
 
-std::string hashed_keyfile_name(std::string const & priv_key) {
-	constexpr uint8_t const SALT[] = {
-		0x1, 0x6, 0x1, 0x5, 0x5, 0x8, 0x3, 0xd, 0x2, 0x7,
-		0x5, 0xc, 0x8, 0x8, 0x7, 0x2, 0x7, 0xa, 0xf, 0x5,
-		0xa, 0x6, 0xc, 0x5, 0xf, 0xe, 0x6, 0x7, 0xf, 0xd,
-		0x1, 0x5
-	};
+#include "crypto/pubkey.hpp"
 
-	uint8_t const * key = reinterpret_cast<uint8_t const *>(priv_key.c_str());
-	uint32_t keylen = priv_key.size();
-
-	uint8_t t_cost = 2; // 2-pass computation
-	uint32_t m_cost = 1 << 17; // 128 mebibytes memory
-	uint32_t parallelism = 1; // single thread
-
-	constexpr size_t HASHLEN = 32;
-
-	uint8_t hash[HASHLEN];
+extern "C" {
+	#include "crypto/halfsiphash.h"
+}
 
-	argon2id_hash_raw(t_cost, m_cost, parallelism, key, keylen, SALT, sizeof(SALT), hash, HASHLEN);
+constexpr char const * PRIVATE_KEY_SUFFIX = ".privkey";
+constexpr char const * SYMMETRIC_KEY_SUFFIX = ".symkey";
 
-	constexpr char KEYFILE_EXT[] = ".keyfile";
 
-	char filename[HASHLEN + sizeof(KEYFILE_EXT)];
+namespace wg2nd {
+	std::string private_keyfile_name(std::string const & priv_key) {
+		char pub_key[WG_KEY_LEN_BASE64];
 
-	constexpr char const HEX[] = "0123456789abcdefghijklmnopqrstuv";
+		// Derive public key
+		if(wg_pubkey_base64(priv_key.c_str(), pub_key)) {
+				throw ParsingException("Private key is formatted improperly");
+		}
 
-	for(size_t i = 0; i < HASHLEN; i++) {
-		filename[i] = HEX[hash[i] & 0x1F];
-	}
+		std::string keyfile_name { pub_key };
+		keyfile_name.append(PRIVATE_KEY_SUFFIX);
 
-	// copy null terminator
-	for(size_t i = 0; i < sizeof(KEYFILE_EXT); i++) {
-		filename[HASHLEN + i] = KEYFILE_EXT[i];
+		return keyfile_name;
 	}
 
-	return std::string { filename } ;
-}
-
-uint32_t deterministic_fwmark(std::string const & interface_name) {
-	constexpr uint8_t const SALT[] = {
-		0x90, 0x08, 0x82, 0xd7, 0x75, 0x68, 0xf4, 0x8e,
-		0x90, 0x74, 0x0c, 0x74, 0x0d, 0xf4, 0xfb, 0x91,
-		0xe5, 0x44, 0x87, 0x7e, 0xce, 0x48, 0xcf, 0x01,
-	};
-
-	uint8_t const * key = reinterpret_cast<uint8_t const *>(interface_name.c_str());
-	uint32_t keylen = interface_name.size();
-
-	uint32_t mark;
-
-	uint8_t t_cost = 2;
-	uint32_t m_cost = 1 << 10;
-	uint32_t parallelism = 1;
-
-	argon2id_hash_raw(t_cost, m_cost, parallelism, key, keylen, SALT, sizeof(SALT), &mark, sizeof(mark));
+	uint32_t deterministic_fwmark(std::string const & interface_name) {
+		constexpr uint8_t const SIP_KEY[8] = {
+			0x90, 0x08, 0x82, 0xd7,
+			0x75, 0x68, 0xf4, 0x8e,
+		};
 
-	return mark;
-}
+		uint32_t mark;
 
+		halfsiphash(interface_name.c_str(), interface_name.size(), SIP_KEY, (uint8_t *) &mark, sizeof(mark));
 
-namespace wg2nd {
+		return mark;
+	}
 
 	std::string interface_name_from_filename(std::filesystem::path config_path) {
 		std::string interface_name = config_path.filename().string();
@@ -429,7 +403,7 @@ namespace wg2nd {
 			}
 
 			if(!peer.preshared_key.empty()) {
-				std::string filename = hashed_keyfile_name(peer.preshared_key);
+				std::string filename = peer.public_key + SYMMETRIC_KEY_SUFFIX;
 
 				symmetric_keyfiles.push_back(SystemdFilespec {
 					.name = filename,
@@ -582,7 +556,7 @@ namespace wg2nd {
 		if(keyfile_or_output_path.has_filename()) {
 			keyfile_path = keyfile_or_output_path;
 		} else {
-			std::string private_keyfile = hashed_keyfile_name(cfg.intf.private_key);
+			std::string private_keyfile = private_keyfile_name(cfg.intf.private_key);
 			keyfile_path = keyfile_or_output_path / private_keyfile;
 		}