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-rw-r--r--curve25519-tweetnacl.c169
1 files changed, 0 insertions, 169 deletions
diff --git a/curve25519-tweetnacl.c b/curve25519-tweetnacl.c
deleted file mode 100644
index 91e86a3..0000000
--- a/curve25519-tweetnacl.c
+++ /dev/null
@@ -1,169 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0
- *
- * Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
- *
- * Curve25519 ECDH functions, based on TweetNaCl but cleaned up.
- */
-
-#include <linux/kernel.h>
-#include <linux/string.h>
-
-enum { CURVE25519_POINT_SIZE = 32 };
-
-static __always_inline void normalize_secret(u8 secret[CURVE25519_POINT_SIZE])
-{
- secret[0] &= 248;
- secret[31] &= 127;
- secret[31] |= 64;
-}
-
-typedef s64 fe[16];
-
-static inline void carry(fe o)
-{
- int i;
-
- for (i = 0; i < 16; ++i) {
- o[(i + 1) % 16] += (i == 15 ? 38 : 1) * (o[i] >> 16);
- o[i] &= 0xffff;
- }
-}
-
-static inline void cswap(fe p, fe q, int b)
-{
- int i;
- s64 t, c = ~(b - 1);
-
- for (i = 0; i < 16; ++i) {
- t = c & (p[i] ^ q[i]);
- p[i] ^= t;
- q[i] ^= t;
- }
-}
-
-static inline void pack(u8 *o, const fe n)
-{
- int i, j, b;
- fe m, t;
-
- memcpy(t, n, sizeof(t));
- carry(t);
- carry(t);
- carry(t);
- for (j = 0; j < 2; ++j) {
- m[0] = t[0] - 0xffed;
- for (i = 1; i < 15; ++i) {
- m[i] = t[i] - 0xffff - ((m[i - 1] >> 16) & 1);
- m[i - 1] &= 0xffff;
- }
- m[15] = t[15] - 0x7fff - ((m[14] >> 16) & 1);
- b = (m[15] >> 16) & 1;
- m[14] &= 0xffff;
- cswap(t, m, 1 - b);
- }
- for (i = 0; i < 16; ++i) {
- o[2 * i] = t[i] & 0xff;
- o[2 * i + 1] = t[i] >> 8;
- }
-}
-
-static inline void unpack(fe o, const u8 *n)
-{
- int i;
-
- for (i = 0; i < 16; ++i)
- o[i] = n[2 * i] + ((s64)n[2 * i + 1] << 8);
- o[15] &= 0x7fff;
-}
-
-static inline void add(fe o, const fe a, const fe b)
-{
- int i;
-
- for (i = 0; i < 16; ++i)
- o[i] = a[i] + b[i];
-}
-
-static inline void subtract(fe o, const fe a, const fe b)
-{
- int i;
-
- for (i = 0; i < 16; ++i)
- o[i] = a[i] - b[i];
-}
-
-static inline void multmod(fe o, const fe a, const fe b)
-{
- int i, j;
- s64 t[31] = { 0 };
-
- for (i = 0; i < 16; ++i) {
- for (j = 0; j < 16; ++j)
- t[i + j] += a[i] * b[j];
- }
- for (i = 0; i < 15; ++i)
- t[i] += 38 * t[i + 16];
- memcpy(o, t, sizeof(fe));
- carry(o);
- carry(o);
-}
-
-static inline void invert(fe o, const fe i)
-{
- fe c;
- int a;
-
- memcpy(c, i, sizeof(c));
- for (a = 253; a >= 0; --a) {
- multmod(c, c, c);
- if (a != 2 && a != 4)
- multmod(c, c, i);
- }
- memcpy(o, c, sizeof(fe));
-}
-
-bool curve25519_tweetnacl(u8 shared_secret[CURVE25519_POINT_SIZE], const u8 private_key[CURVE25519_POINT_SIZE], const u8 public_key[CURVE25519_POINT_SIZE])
-{
- static const fe a24 = { 0xdb41, 1 };
- u8 z[32];
- s64 r;
- int i;
- fe a = { 1 }, b, c = { 0 }, d = { 1 }, e, f, x;
-
- memcpy(z, private_key, sizeof(z));
- normalize_secret(z);
-
- unpack(x, public_key);
- memcpy(b, x, sizeof(b));
-
- for (i = 254; i >= 0; --i) {
- r = (z[i >> 3] >> (i & 7)) & 1;
- cswap(a, b, r);
- cswap(c, d, r);
- add(e, a, c);
- subtract(a, a, c);
- add(c, b, d);
- subtract(b, b, d);
- multmod(d, e, e);
- multmod(f, a, a);
- multmod(a, c, a);
- multmod(c, b, e);
- add(e, a, c);
- subtract(a, a, c);
- multmod(b, a, a);
- subtract(c, d, f);
- multmod(a, c, a24);
- add(a, a, d);
- multmod(c, c, a);
- multmod(a, d, f);
- multmod(d, b, x);
- multmod(b, e, e);
- cswap(a, b, r);
- cswap(c, d, r);
- }
- invert(c, c);
- multmod(a, a, c);
- pack(shared_secret, a);
-
- return true;
-}