From: Thomas Pornin <pornin@bolet.org>
Date: Sun, 15 Jan 2017 02:32:13 +0000 (+0100)
Subject: New basic implementation of Curve25519 (generic i15 code, experimental).
X-Git-Tag: v0.4~20
X-Git-Url: https://www.bearssl.org/gitweb//home/git/?p=BearSSL;a=commitdiff_plain;h=2f9c953af45299f8546df8984d5262e767a7d943

New basic implementation of Curve25519 (generic i15 code, experimental).
---

diff --git a/Makefile b/Makefile
index 4c627f5..ac5f241 100644
--- a/Makefile
+++ b/Makefile
@@ -47,7 +47,7 @@ TESTX509 = testx509
 TESTMATH = testmath
 
 OBJCODEC = $(BUILD)/ccopy.o $(BUILD)/dec16be.o $(BUILD)/dec16le.o $(BUILD)/dec32be.o $(BUILD)/dec32le.o $(BUILD)/dec64be.o $(BUILD)/dec64le.o $(BUILD)/enc16be.o $(BUILD)/enc16le.o $(BUILD)/enc32be.o $(BUILD)/enc32le.o $(BUILD)/enc64be.o $(BUILD)/enc64le.o $(BUILD)/pemdec.o
-OBJEC = $(BUILD)/ec_p256_i15.o $(BUILD)/ec_prime_i15.o $(BUILD)/ec_prime_i31.o $(BUILD)/ec_secp256r1.o $(BUILD)/ec_secp384r1.o $(BUILD)/ec_secp521r1.o $(BUILD)/ecdsa_atr.o $(BUILD)/ecdsa_i15_bits.o $(BUILD)/ecdsa_i15_sign_asn1.o $(BUILD)/ecdsa_i15_sign_raw.o $(BUILD)/ecdsa_i15_vrfy_asn1.o $(BUILD)/ecdsa_i15_vrfy_raw.o $(BUILD)/ecdsa_i31_bits.o $(BUILD)/ecdsa_i31_sign_asn1.o $(BUILD)/ecdsa_i31_sign_raw.o $(BUILD)/ecdsa_i31_vrfy_asn1.o $(BUILD)/ecdsa_i31_vrfy_raw.o $(BUILD)/ecdsa_rta.o
+OBJEC = $(BUILD)/ec_c25519_i15.o $(BUILD)/ec_curve25519.o $(BUILD)/ec_p256_m15.o $(BUILD)/ec_prime_i15.o $(BUILD)/ec_prime_i31.o $(BUILD)/ec_secp256r1.o $(BUILD)/ec_secp384r1.o $(BUILD)/ec_secp521r1.o $(BUILD)/ecdsa_atr.o $(BUILD)/ecdsa_i15_bits.o $(BUILD)/ecdsa_i15_sign_asn1.o $(BUILD)/ecdsa_i15_sign_raw.o $(BUILD)/ecdsa_i15_vrfy_asn1.o $(BUILD)/ecdsa_i15_vrfy_raw.o $(BUILD)/ecdsa_i31_bits.o $(BUILD)/ecdsa_i31_sign_asn1.o $(BUILD)/ecdsa_i31_sign_raw.o $(BUILD)/ecdsa_i31_vrfy_asn1.o $(BUILD)/ecdsa_i31_vrfy_raw.o $(BUILD)/ecdsa_rta.o
 # $(BUILD)/ec_prime_i31_secp256r1.o $(BUILD)/ec_prime_i31_secp384r1.o $(BUILD)/ec_prime_i31_secp521r1.o
 OBJHASH = $(BUILD)/dig_oid.o $(BUILD)/dig_size.o $(BUILD)/ghash_ctmul.o $(BUILD)/ghash_ctmul32.o $(BUILD)/ghash_ctmul64.o $(BUILD)/md5.o $(BUILD)/md5sha1.o $(BUILD)/multihash.o $(BUILD)/sha1.o $(BUILD)/sha2big.o $(BUILD)/sha2small.o
 OBJINT15 = $(BUILD)/i15_core.o $(BUILD)/i15_ext1.o $(BUILD)/i15_ext2.o
@@ -162,8 +162,14 @@ $(BUILD)/ec_g_secp384r1.o: src/ec/ec_g_secp384r1.c $(HEADERS)
 $(BUILD)/ec_g_secp521r1.o: src/ec/ec_g_secp521r1.c $(HEADERS)
 	$(CC) $(CFLAGS) -c -o $(BUILD)/ec_g_secp521r1.o src/ec/ec_g_secp521r1.c
 
-$(BUILD)/ec_p256_i15.o: src/ec/ec_p256_i15.c $(HEADERS)
-	$(CC) $(CFLAGS) -c -o $(BUILD)/ec_p256_i15.o src/ec/ec_p256_i15.c
+$(BUILD)/ec_c25519_i15.o: src/ec/ec_c25519_i15.c $(HEADERS)
+	$(CC) $(CFLAGS) -c -o $(BUILD)/ec_c25519_i15.o src/ec/ec_c25519_i15.c
+
+$(BUILD)/ec_curve25519.o: src/ec/ec_curve25519.c $(HEADERS)
+	$(CC) $(CFLAGS) -c -o $(BUILD)/ec_curve25519.o src/ec/ec_curve25519.c
+
+$(BUILD)/ec_p256_m15.o: src/ec/ec_p256_m15.c $(HEADERS)
+	$(CC) $(CFLAGS) -c -o $(BUILD)/ec_p256_m15.o src/ec/ec_p256_m15.c
 
 $(BUILD)/ec_prime_i15.o: src/ec/ec_prime_i15.c $(HEADERS)
 	$(CC) $(CFLAGS) -c -o $(BUILD)/ec_prime_i15.o src/ec/ec_prime_i15.c
diff --git a/inc/bearssl_ec.h b/inc/bearssl_ec.h
index 908d532..2c84bad 100644
--- a/inc/bearssl_ec.h
+++ b/inc/bearssl_ec.h
@@ -218,6 +218,12 @@
 /** \brief Identifier for named curve brainpoolP512r1. */
 #define BR_EC_brainpoolP512r1    28
 
+/** \brief Identifier for named curve Curve25519. */
+#define BR_EC_curve25519         29
+
+/** \brief Identifier for named curve Curve448. */
+#define BR_EC_curve448           30
+
 /**
  * \brief Structure for an EC public key.
  */
@@ -411,7 +417,16 @@ extern const br_ec_impl br_ec_prime_i15;
  * reduction thanks to the field modulus special format. Only 32-bit
  * multiplications are used (with 32-bit results, not 64-bit).
  */
-extern const br_ec_impl br_ec_p256_i15;
+extern const br_ec_impl br_ec_p256_m15;
+
+/**
+ * \brief EC implementation "i15" (generic code) for Curve25519.
+ *
+ * This implementation uses the generic code for modular integers (with
+ * 15-bit words) to support Curve25519. The `muladd()` method is not
+ * implemented.
+ */
+extern const br_ec_impl br_ec_c25519_i15;
 
 /**
  * \brief Convert a signature from "raw" to "asn1".
diff --git a/src/ec/ec_c25519_i15.c b/src/ec/ec_c25519_i15.c
new file mode 100644
index 0000000..79560ae
--- /dev/null
+++ b/src/ec/ec_c25519_i15.c
@@ -0,0 +1,303 @@
+/*
+ * Copyright (c) 2017 Thomas Pornin <pornin@bolet.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining 
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be 
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "inner.h"
+
+/*
+ * Parameters for the field:
+ *   - field modulus p = 2^255-19
+ *   - R^2 mod p (R = 2^(15k) for the smallest k such that R >= p)
+ */
+
+static const uint16_t C255_P[] = {
+	0x0110,
+	0x7FED, 0x7FFF, 0x7FFF, 0x7FFF, 0x7FFF, 0x7FFF, 0x7FFF, 0x7FFF,
+	0x7FFF, 0x7FFF, 0x7FFF, 0x7FFF, 0x7FFF, 0x7FFF, 0x7FFF, 0x7FFF,
+	0x7FFF
+};
+
+#define P0I   0x4A1B
+
+static const uint16_t C255_R2[] = {
+	0x0110,
+	0x0169, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+	0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+	0x0000
+};
+
+static const uint16_t C255_A24[] = {
+	0x0110,
+	0x45D3, 0x0046, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+	0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+	0x0000
+};
+
+static const unsigned char GEN[] = {
+	0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+};
+
+static const unsigned char ORDER[] = {
+	0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x14, 0xDE, 0xF9, 0xDE, 0xA2, 0xF7, 0x9C, 0xD6,
+	0x58, 0x12, 0x63, 0x1A, 0x5C, 0xF5, 0xD3, 0xED
+};
+
+static const unsigned char *
+api_generator(int curve, size_t *len)
+{
+	(void)curve;
+	*len = 32;
+	return GEN;
+}
+
+static const unsigned char *
+api_order(int curve, size_t *len)
+{
+	(void)curve;
+	*len = 32;
+	return ORDER;
+}
+
+static void
+cswap(uint16_t *a, uint16_t *b, uint32_t ctl)
+{
+	int i;
+
+	ctl = -ctl;
+	for (i = 0; i < 18; i ++) {
+		uint32_t aw, bw, tw;
+
+		aw = a[i];
+		bw = b[i];
+		tw = ctl & (aw ^ bw);
+		a[i] = aw ^ tw;
+		b[i] = bw ^ tw;
+	}
+}
+
+static void
+c255_add(uint16_t *d, const uint16_t *a, const uint16_t *b)
+{
+	uint32_t ctl;
+	uint16_t t[18];
+
+	memcpy(t, a, sizeof t);
+	ctl = br_i15_add(t, b, 1);
+	ctl |= NOT(br_i15_sub(t, C255_P, 0));
+	br_i15_sub(t, C255_P, ctl);
+	memcpy(d, t, sizeof t);
+}
+
+static void
+c255_sub(uint16_t *d, const uint16_t *a, const uint16_t *b)
+{
+	uint16_t t[18];
+
+	memcpy(t, a, sizeof t);
+	br_i15_add(t, C255_P, br_i15_sub(t, b, 1));
+	memcpy(d, t, sizeof t);
+}
+
+static void
+c255_mul(uint16_t *d, const uint16_t *a, const uint16_t *b)
+{
+	uint16_t t[18];
+
+	br_i15_montymul(t, a, b, C255_P, P0I);
+	memcpy(d, t, sizeof t);
+}
+
+static void
+byteswap(unsigned char *G)
+{
+	int i;
+
+	for (i = 0; i < 16; i ++) {
+		unsigned char t;
+
+		t = G[i];
+		G[i] = G[31 - i];
+		G[31 - i] = t;
+	}
+}
+
+static uint32_t
+api_mul(unsigned char *G, size_t Glen,
+	const unsigned char *kb, size_t kblen, int curve)
+{
+	uint16_t x1[18], x2[18], x3[18], z2[18], z3[18];
+	uint16_t a[18], aa[18], b[18], bb[18];
+	uint16_t c[18], d[18], e[18], da[18], cb[18];
+	unsigned char k[32];
+	uint32_t swap;
+	int i;
+
+	(void)curve;
+
+	/*
+	 * Points are encoded over exactly 32 bytes. Multipliers must fit
+	 * in 32 bytes as well.
+	 * RFC 7748 mandates that the high bit of the last point byte must
+	 * be ignored/cleared.
+	 */
+	if (Glen != 32 || kblen > 32) {
+		return 0;
+	}
+	G[31] &= 0x7F;
+
+	/*
+	 * Byteswap the point encoding, because it uses little-endian, and
+	 * the generic decoding routine uses big-endian.
+	 */
+	byteswap(G);
+
+	/*
+	 * Initialise variables x1, x2, z2, x3 and z3. We set all of them
+	 * into Montgomery representation.
+	 */
+	br_i15_decode_reduce(a, G, 32, C255_P);
+	br_i15_montymul(x1, a, C255_R2, C255_P, P0I);
+	memcpy(x3, x1, sizeof x1);
+	br_i15_zero(z2, C255_P[0]);
+	memcpy(x2, z2, sizeof z2);
+	x2[1] = 19;
+	memcpy(z3, x2, sizeof x2);
+
+	memcpy(k, kb, kblen);
+	memset(k + kblen, 0, (sizeof k) - kblen);
+	k[0] &= 0xF8;
+	k[31] &= 0x7F;
+	k[31] |= 0x40;
+
+	swap = 0;
+	for (i = 254; i >= 0; i --) {
+		uint32_t kt;
+
+		kt = (k[i >> 3] >> (i & 7)) & 1;
+		swap ^= kt;
+		cswap(x2, x3, swap);
+		cswap(z2, z3, swap);
+		swap = kt;
+
+		c255_add(a, x2, z2);
+		c255_mul(aa, a, a);
+		c255_sub(b, x2, z2);
+		c255_mul(bb, b, b);
+		c255_sub(e, aa, bb);
+		c255_add(c, x3, z3);
+		c255_sub(d, x3, z3);
+		c255_mul(da, d, a);
+		c255_mul(cb, c, b);
+		c255_add(x3, da, cb);
+		c255_mul(x3, x3, x3);
+		c255_sub(z3, da, cb);
+		c255_mul(z3, z3, z3);
+		c255_mul(z3, z3, x1);
+		c255_mul(x2, aa, bb);
+		c255_mul(z2, C255_A24, e);
+		c255_add(z2, z2, aa);
+		c255_mul(z2, e, z2);
+	}
+	cswap(x2, x3, swap);
+	cswap(z2, z3, swap);
+
+	/*
+	 * Inverse z2 with a modular exponentiation. This is a simple
+	 * square-and-multiply algorithm; we mutualise most non-squarings
+	 * since the exponent contains almost only ones.
+	 */
+	memcpy(a, z2, sizeof z2);
+	for (i = 0; i < 15; i ++) {
+		c255_mul(a, a, a);
+		c255_mul(a, a, z2);
+	}
+	memcpy(b, a, sizeof a);
+	for (i = 0; i < 14; i ++) {
+		int j;
+
+		for (j = 0; j < 16; j ++) {
+			c255_mul(b, b, b);
+		}
+		c255_mul(b, b, a);
+	}
+	for (i = 14; i >= 0; i --) {
+		c255_mul(b, b, b);
+		if ((0xFFEB >> i) & 1) {
+			c255_mul(b, z2, b);
+		}
+	}
+	c255_mul(x2, x2, b);
+	br_i15_from_monty(x2, C255_P, P0I);
+	br_i15_encode(G, 32, x2);
+	byteswap(G);
+	return 1;
+}
+
+static size_t
+api_mulgen(unsigned char *R,
+	const unsigned char *x, size_t xlen, int curve)
+{
+	const unsigned char *G;
+	size_t Glen;
+
+	G = api_generator(curve, &Glen);
+	memcpy(R, G, Glen);
+	api_mul(R, Glen, x, xlen, curve);
+	return Glen;
+}
+
+static uint32_t
+api_muladd(unsigned char *A, const unsigned char *B, size_t len,
+	const unsigned char *x, size_t xlen,
+	const unsigned char *y, size_t ylen, int curve)
+{
+	/*
+	 * We don't implement this method, since it is used for ECDSA
+	 * only, and there is no ECDSA over Curve25519 (which instead
+	 * uses EdDSA).
+	 */
+	(void)A;
+	(void)B;
+	(void)len;
+	(void)x;
+	(void)xlen;
+	(void)y;
+	(void)ylen;
+	(void)curve;
+	return 0;
+}
+
+/* see bearssl_ec.h */
+const br_ec_impl br_ec_c25519_i15 = {
+	(uint32_t)0x20000000,
+	&api_generator,
+	&api_order,
+	&api_mul,
+	&api_mulgen,
+	&api_muladd
+};
diff --git a/src/ec/ec_curve25519.c b/src/ec/ec_curve25519.c
new file mode 100644
index 0000000..de1a8f8
--- /dev/null
+++ b/src/ec/ec_curve25519.c
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2017 Thomas Pornin <pornin@bolet.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining 
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be 
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "inner.h"
+
+static const unsigned char GEN[] = {
+	0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+};
+
+static const unsigned char ORDER[] = {
+	0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x14, 0xDE, 0xF9, 0xDE, 0xA2, 0xF7, 0x9C, 0xD6,
+	0x58, 0x12, 0x63, 0x1A, 0x5C, 0xF5, 0xD3, 0xED
+};
+
+/* see inner.h */
+const br_ec_curve_def br_curve25519 = {
+	BR_EC_curve25519,
+	ORDER, sizeof ORDER,
+	GEN, sizeof GEN
+};
diff --git a/src/ec/ec_p256_i15.c b/src/ec/ec_p256_m15.c
similarity index 99%
rename from src/ec/ec_p256_i15.c
rename to src/ec/ec_p256_m15.c
index 68ab73a..99c7224 100644
--- a/src/ec/ec_p256_i15.c
+++ b/src/ec/ec_p256_m15.c
@@ -2075,7 +2075,7 @@ api_muladd(unsigned char *A, const unsigned char *B, size_t len,
 }
 
 /* see bearssl_ec.h */
-const br_ec_impl br_ec_p256_i15 = {
+const br_ec_impl br_ec_p256_m15 = {
 	(uint32_t)0x00800000,
 	&api_generator,
 	&api_order,
diff --git a/src/inner.h b/src/inner.h
index fd764bc..9123a42 100644
--- a/src/inner.h
+++ b/src/inner.h
@@ -1456,6 +1456,8 @@ extern const br_ec_curve_def br_secp256r1;
 extern const br_ec_curve_def br_secp384r1;
 extern const br_ec_curve_def br_secp521r1;
 
+extern const br_ec_curve_def br_curve25519;
+
 #if 0
 /* obsolete */
 /*
diff --git a/src/int/i15_core.c b/src/int/i15_core.c
index 5ae3b31..a33469a 100644
--- a/src/int/i15_core.c
+++ b/src/int/i15_core.c
@@ -263,7 +263,8 @@ br_i15_montymul(uint16_t *d, const uint16_t *x, const uint16_t *y,
 		uint32_t f, xu, r, zh;
 
 		xu = x[u + 1];
-		f = MUL15(d[1] + MUL15(x[u + 1], y[1]), m0i) & 0x7FFF;
+		f = MUL15((d[1] + MUL15(x[u + 1], y[1])) & 0x7FFF, m0i)
+			& 0x7FFF;
 
 		r = 0;
 		for (v = 0; v < len4; v += 4) {
@@ -297,7 +298,7 @@ br_i15_montymul(uint16_t *d, const uint16_t *x, const uint16_t *y,
 
 		zh = dh + r;
 		d[len] = zh & 0x7FFF;
-		dh = zh >> 31;
+		dh = zh >> 15;
 	}
 
 	/*
diff --git a/test/test_crypto.c b/test/test_crypto.c
index 69b6f7d..ddba9ac 100644
--- a/test/test_crypto.c
+++ b/test/test_crypto.c
@@ -4912,12 +4912,60 @@ test_EC_prime_i31(void)
 }
 
 static void
-test_EC_p256_i15(void)
+test_EC_p256_m15(void)
 {
-	test_EC_KAT("EC_p256_i15", &br_ec_p256_i15,
+	test_EC_KAT("EC_p256_m15", &br_ec_p256_m15,
 		(uint32_t)1 << BR_EC_secp256r1);
 }
 
+const struct {
+	const char *scalar;
+	const char *u_in;
+	const char *u_out;
+} C25519_KAT[] = {
+	{ "A546E36BF0527C9D3B16154B82465EDD62144C0AC1FC5A18506A2244BA449AC4",
+	  "E6DB6867583030DB3594C1A424B15F7C726624EC26B3353B10A903A6D0AB1C4C",
+	  "C3DA55379DE9C6908E94EA4DF28D084F32ECCF03491C71F754B4075577A28552" },
+	{ "4B66E9D4D1B4673C5AD22691957D6AF5C11B6421E0EA01D42CA4169E7918BA0D",
+	  "E5210F12786811D3F4B7959D0538AE2C31DBE7106FC03C3EFC4CD549C715A493",
+	  "95CBDE9476E8907D7AADE45CB4B873F88B595A68799FA152E6F8F7647AAC7957" },
+	{ 0, 0, 0 }
+};
+
+static void
+test_EC_c25519(const char *name, const br_ec_impl *iec)
+{
+	size_t v;
+
+	printf("Test %s: ", name);
+	fflush(stdout);
+	for (v = 0; C25519_KAT[v].scalar; v ++) {
+		unsigned char bu[32], bk[32], br[32];
+
+		hextobin(bk, C25519_KAT[v].scalar);
+		hextobin(bu, C25519_KAT[v].u_in);
+		hextobin(br, C25519_KAT[v].u_out);
+		if (!iec->mul(bu, sizeof bu, bk, sizeof bk, BR_EC_curve25519)) {
+			fprintf(stderr, "Curve25519 multiplication failed\n");
+			exit(EXIT_FAILURE);
+		}
+		if (memcmp(bu, br, sizeof bu) != 0) {
+			fprintf(stderr, "Curve25519 failed KAT\n");
+			exit(EXIT_FAILURE);
+		}
+		printf(".");
+		fflush(stdout);
+	}
+	printf(" done.\n");
+	fflush(stdout);
+}
+
+static void
+test_EC_c25519_i15(void)
+{
+	test_EC_c25519("EC_c25519_i15", &br_ec_c25519_i15);
+}
+
 static const unsigned char EC_P256_PUB_POINT[] = {
 	0x04, 0x60, 0xFE, 0xD4, 0xBA, 0x25, 0x5A, 0x9D,
 	0x31, 0xC9, 0x61, 0xEB, 0x74, 0xC6, 0x35, 0x6D,
@@ -5462,8 +5510,9 @@ static const struct {
 	STU(GHASH_ctmul64),
 	STU(EC_prime_i15),
 	STU(EC_prime_i31),
-	STU(EC_p256_i15),
+	STU(EC_p256_m15),
 	/* STU(EC_prime_i32), */
+	STU(EC_c25519_i15),
 	STU(ECDSA_i15),
 	STU(ECDSA_i31),
 	{ 0, 0 }
diff --git a/test/test_speed.c b/test/test_speed.c
index 47fed91..48f5fe3 100644
--- a/test/test_speed.c
+++ b/test/test_speed.c
@@ -685,10 +685,10 @@ test_speed_ec_inner(const char *name,
 }
 
 static void
-test_speed_ec_p256_i15(void)
+test_speed_ec_p256_m15(void)
 {
-	test_speed_ec_inner("EC i15/spec P-256",
-		&br_ec_p256_i15, &br_secp256r1);
+	test_speed_ec_inner("EC m15 P-256",
+		&br_ec_p256_m15, &br_secp256r1);
 }
 
 static void
@@ -707,6 +707,13 @@ test_speed_ec_prime_i31(void)
 	test_speed_ec_inner("EC i31 P-521", &br_ec_prime_i31, &br_secp521r1);
 }
 
+static void
+test_speed_ec_c25519_i15(void)
+{
+	test_speed_ec_inner("EC i15 C25519",
+		&br_ec_c25519_i15, &br_curve25519);
+}
+
 static void
 test_speed_ecdsa_inner(const char *name,
 	const br_ec_impl *impl, const br_ec_curve_def *cd,
@@ -793,10 +800,10 @@ test_speed_ecdsa_inner(const char *name,
 }
 
 static void
-test_speed_ecdsa_p256_i15(void)
+test_speed_ecdsa_p256_m15(void)
 {
-	test_speed_ecdsa_inner("ECDSA i15 P-256 (spec)",
-		&br_ec_p256_i15, &br_secp256r1,
+	test_speed_ecdsa_inner("ECDSA m15 P-256",
+		&br_ec_p256_m15, &br_secp256r1,
 		&br_ecdsa_i15_sign_asn1,
 		&br_ecdsa_i15_vrfy_asn1);
 }
@@ -1245,10 +1252,11 @@ static const struct {
 	STU(rsa_i15),
 	STU(rsa_i31),
 	STU(rsa_i32),
-	STU(ec_p256_i15),
+	STU(ec_p256_m15),
 	STU(ec_prime_i15),
 	STU(ec_prime_i31),
-	STU(ecdsa_p256_i15),
+	STU(ec_c25519_i15),
+	STU(ecdsa_p256_m15),
 	STU(ecdsa_i15),
 	STU(ecdsa_i31),