#include "monocypher.h"
/////////////////
/// Utilities ///
/////////////////
// By default, EdDSA signatures use blake2b. SHA-512 is provided as an
// option for full ed25519 compatibility. To use with SHA-512, compile
// with option -DED25519_SHA512 and provide the "sha512" header.
#ifdef ED25519_SHA512
#define HASH crypto_sha512
#else
#define HASH crypto_blake2b
#endif
#define COMBINE1(x, y) x ## y
#define COMBINE2(x, y) COMBINE1(x, y)
#define HASH_CTX COMBINE2(HASH, _ctx)
#define HASH_INIT COMBINE2(HASH, _init)
#define HASH_UPDATE COMBINE2(HASH, _update)
#define HASH_FINAL COMBINE2(HASH, _final)
#define FOR(i, start, end) for (size_t (i) = (start); (i) < (end); (i)++)
#define WIPE_CTX(ctx) crypto_wipe(ctx , sizeof(*(ctx)))
#define WIPE_BUFFER(buffer) crypto_wipe(buffer, sizeof(buffer))
#define MIN(a, b) ((a) <= (b) ? (a) : (b))
#define ALIGN(x, block_size) ((~(x) + 1) & ((block_size) - 1))
typedef int8_t i8;
typedef uint8_t u8;
typedef uint32_t u32;
typedef int32_t i32;
typedef int64_t i64;
typedef uint64_t u64;
static const u8 zero[128] = {0};
static u32 load24_le(const u8 s[3])
{
return (u32)s[0]
| ((u32)s[1] << 8)
| ((u32)s[2] << 16);
}
static u32 load32_le(const u8 s[4])
{
return (u32)s[0]
| ((u32)s[1] << 8)
| ((u32)s[2] << 16)
| ((u32)s[3] << 24);
}
static u64 load64_le(const u8 s[8])
{
return load32_le(s) | ((u64)load32_le(s+4) << 32);
}
static void store32_le(u8 out[4], u32 in)
{
out[0] = in & 0xff;
out[1] = (in >> 8) & 0xff;
out[2] = (in >> 16) & 0xff;
out[3] = (in >> 24) & 0xff;
}
static void store64_le(u8 out[8], u64 in)
{
store32_le(out , (u32)in );
store32_le(out + 4, in >> 32);
}
static u64 rotr64(u64 x, u64 n) { return (x >> n) ^ (x << (64 - n)); }
static u32 rotl32(u32 x, u32 n) { return (x << n) ^ (x >> (32 - n)); }
static int neq0(u64 diff)
{ // constant time comparison to zero
// return diff != 0 ? -1 : 0
u64 half = (diff >> 32) | ((u32)diff);
return (1 & ((half - 1) >> 32)) - 1;
}
static u64 x16(const u8 a[16], const u8 b[16])
{
return (load64_le(a + 0) ^ load64_le(b + 0))
| (load64_le(a + 8) ^ load64_le(b + 8));
}
static u64 x32(const u8 a[16],const u8 b[16]){return x16(a,b)| x16(a+16, b+16);}
static u64 x64(const u8 a[64],const u8 b[64]){return x32(a,b)| x32(a+32, b+32);}
int crypto_verify16(const u8 a[16], const u8 b[16]){ return neq0(x16(a, b)); }
int crypto_verify32(const u8 a[32], const u8 b[32]){ return neq0(x32(a, b)); }
int crypto_verify64(const u8 a[64], const u8 b[64]){ return neq0(x64(a, b)); }
static int zerocmp32(const u8 p[32])
{
return crypto_verify32(p, zero);
}
void crypto_wipe(void *secret, size_t size)
{
volatile u8 *v_secret = (u8*)secret;
FOR (i, 0, size) {
v_secret[i] = 0;
}
}
/////////////////
/// Chacha 20 ///
/////////////////
#define QUARTERROUND(a, b, c, d) \
a += b; d = rotl32(d ^ a, 16); \
c += d; b = rotl32(b ^ c, 12); \
a += b; d = rotl32(d ^ a, 8); \
c += d; b = rotl32(b ^ c, 7)
static void chacha20_rounds(u32 out[16], const u32 in[16])
{
// The temporary variables make Chacha20 10% faster.
u32 t0 = in[ 0]; u32 t1 = in[ 1]; u32 t2 = in[ 2]; u32 t3 = in[ 3];
u32 t4 = in[ 4]; u32 t5 = in[ 5]; u32 t6 = in[ 6]; u32 t7 = in[ 7];
u32 t8 = in[ 8]; u32 t9 = in[ 9]; u32 t10 = in[10]; u32 t11 = in[11];
u32 t12 = in[12]; u32 t13 = in[13]; u32 t14 = in[14]; u32 t15 = in[15];
FOR (i, 0, 10) { // 20 rounds, 2 rounds per loop.
QUARTERROUND(t0, t4, t8 , t12); // column 0
QUARTERROUND(t1, t5, t9 , t13); // column 1
QUARTERROUND(t2, t6, t10, t14); // column 2
QUARTERROUND(t3, t7, t11, t15); // column 3
QUARTERROUND(t0, t5, t10, t15); // diagonal 0
QUARTERROUND(t1, t6, t11, t12); // diagonal 1
QUARTERROUND(t2, t7, t8 , t13); // diagonal 2
QUARTERROUND(t3, t4, t9 , t14); // diagonal 3
}
out[ 0] = t0; out[ 1] = t1; out[ 2] = t2; out[ 3] = t3;
out[ 4] = t4; out[ 5] = t5; out[ 6] = t6; out[ 7] = t7;
out[ 8] = t8; out[ 9] = t9; out[10] = t10; out[11] = t11;
out[12] = t12; out[13] = t13; out[14] = t14; out[15] = t15;
}
static void chacha20_init_key(crypto_chacha_ctx *ctx, const u8 key[32])
{
// constant
ctx->input[0] = load32_le((u8*)"expa");
ctx->input[1] = load32_le((u8*)"nd 3");
ctx->input[2] = load32_le((u8*)"2-by");
ctx->input[3] = load32_le((u8*)"te k");
// key
FOR (i, 0, 8) {
ctx->input[i+4] = load32_le(key + i*4);
}
}
static u8 chacha20_pool_byte(crypto_chacha_ctx *ctx)
{
u32 pool_word = ctx->pool[ctx->pool_idx >> 2];
u8 pool_byte = pool_word >> (8*(ctx->pool_idx & 3));
ctx->pool_idx++;
return pool_byte;
}
// Fill the pool if needed, update the counters
static void chacha20_refill_pool(crypto_chacha_ctx *ctx)
{
chacha20_rounds(ctx->pool, ctx->input);
FOR (j, 0, 16) {
ctx->pool[j] += ctx->input[j];
}
ctx->pool_idx = 0;
ctx->input[12]++;
if (ctx->input[12] == 0) {
ctx->input[13]++;
}
}
void crypto_chacha20_H(u8 out[32], const u8 key[32], const u8 in[16])
{
crypto_chacha_ctx ctx;
chacha20_init_key(&ctx, key);
FOR (i, 0, 4) {
ctx.input[i+12] = load32_le(in + i*4);
}
u32 buffer[16];
chacha20_rounds(buffer, ctx.input);
// prevents reversal of the rounds by revealing only half of the buffer.
FOR (i, 0, 4) {
store32_le(out + i*4, buffer[i ]); // constant
store32_le(out + 16 + i*4, buffer[i + 12]); // counter and nonce
}
WIPE_CTX(&ctx);
WIPE_BUFFER(buffer);
}
static void chacha20_encrypt(crypto_chacha_ctx *ctx,
u8 *cipher_text,
const u8 *plain_text,
size_t text_size)
{
FOR (i, 0, text_size) {
if (ctx->pool_idx == 64) {
chacha20_refill_pool(ctx);
}
u8 plain = 0;
if (plain_text != 0) {
plain = *plain_text;
plain_text++;
}
*cipher_text = chacha20_pool_byte(ctx) ^ plain;
cipher_text++;
}
}
void crypto_chacha20_init(crypto_chacha_ctx *ctx,
const u8 key[32],
const u8 nonce[8])
{
chacha20_init_key (ctx, key); // key
crypto_chacha20_set_ctr(ctx, 0 ); // counter
ctx->input[14] = load32_le(nonce + 0); // nonce
ctx->input[15] = load32_le(nonce + 4); // nonce
}
void crypto_chacha20_x_init(crypto_chacha_ctx *ctx,
const u8 key[32],
const u8 nonce[24])
{
u8 derived_key[32];
crypto_chacha20_H(derived_key, key, nonce);
crypto_chacha20_init(ctx, derived_key, nonce + 16);
WIPE_BUFFER(derived_key);
}
void crypto_chacha20_set_ctr(crypto_chacha_ctx *ctx, u64 ctr)
{
ctx->input[12] = ctr & 0xffffffff;
ctx->input[13] = ctr >> 32;
ctx->pool_idx = 64; // The random pool (re)starts empty
}
void crypto_chacha20_encrypt(crypto_chacha_ctx *ctx,
u8 *cipher_text,
const u8 *plain_text,
size_t text_size)
{
// Align ourselves with block boundaries
size_t align = MIN(ALIGN(ctx->pool_idx, 64), text_size);
chacha20_encrypt(ctx, cipher_text, plain_text, align);
if (plain_text != 0) {
plain_text += align;
}
cipher_text += align;
text_size -= align;
// Process the message block by block
FOR (i, 0, text_size >> 6) { // number of blocks
chacha20_refill_pool(ctx);
if (plain_text != 0) {
FOR (j, 0, 16) {
u32 plain = load32_le(plain_text);
store32_le(cipher_text, ctx->pool[j] ^ plain);
plain_text += 4;
cipher_text += 4;
}
} else {
FOR (j, 0, 16) {
store32_le(cipher_text, ctx->pool[j]);
cipher_text += 4;
}
}
ctx->pool_idx = 64;
}
text_size &= 63;
// remaining bytes
chacha20_encrypt(ctx, cipher_text, plain_text, text_size);
}
void crypto_chacha20_stream(crypto_chacha_ctx *ctx,
uint8_t *stream, size_t size)
{
crypto_chacha20_encrypt(ctx, stream, 0, size);
}
/////////////////
/// Poly 1305 ///
/////////////////
// h = (h + c) * r
// preconditions:
// ctx->h <= 4_ffffffff_ffffffff_ffffffff_ffffffff
// ctx->c <= 1_ffffffff_ffffffff_ffffffff_ffffffff
// ctx->r <= 0ffffffc_0ffffffc_0ffffffc_0fffffff
// Postcondition:
// ctx->h <= 4_ffffffff_ffffffff_ffffffff_ffffffff
static void poly_block(crypto_poly1305_ctx *ctx)
{
// s = h + c, without carry propagation
const u64 s0 = ctx->h[0] + (u64)ctx->c[0]; // s0 <= 1_fffffffe
const u64 s1 = ctx->h[1] + (u64)ctx->c[1]; // s1 <= 1_fffffffe
const u64 s2 = ctx->h[2] + (u64)ctx->c[2]; // s2 <= 1_fffffffe
const u64 s3 = ctx->h[3] + (u64)ctx->c[3]; // s3 <= 1_fffffffe
const u32 s4 = ctx->h[4] + ctx->c[4]; // s4 <= 5
// Local all the things!
const u32 r0 = ctx->r[0]; // r0 <= 0fffffff
const u32 r1 = ctx->r[1]; // r1 <= 0ffffffc
const u32 r2 = ctx->r[2]; // r2 <= 0ffffffc
const u32 r3 = ctx->r[3]; // r3 <= 0ffffffc
const u32 rr0 = (r0 >> 2) * 5; // rr0 <= 13fffffb // lose 2 bits...
const u32 rr1 = (r1 >> 2) + r1; // rr1 <= 13fffffb // rr1 == (r1 >> 2) * 5
const u32 rr2 = (r2 >> 2) + r2; // rr2 <= 13fffffb // rr1 == (r2 >> 2) * 5
const u32 rr3 = (r3 >> 2) + r3; // rr3 <= 13fffffb // rr1 == (r3 >> 2) * 5
// (h + c) * r, without carry propagation
const u64 x0 = s0*r0 + s1*rr3 + s2*rr2 + s3*rr1 +s4*rr0;//<=97ffffe007fffff8
const u64 x1 = s0*r1 + s1*r0 + s2*rr3 + s3*rr2 +s4*rr1;//<=8fffffe20ffffff6
const u64 x2 = s0*r2 + s1*r1 + s2*r0 + s3*rr3 +s4*rr2;//<=87ffffe417fffff4
const u64 x3 = s0*r3 + s1*r2 + s2*r1 + s3*r0 +s4*rr3;//<=7fffffe61ffffff2
const u32 x4 = s4 * (r0 & 3); // ...recover 2 bits //<= f
// partial reduction modulo 2^130 - 5
const u32 u5 = x4 + (x3 >> 32); // u5 <= 7ffffff5
const u64 u0 = (u5 >> 2) * 5 + (x0 & 0xffffffff);
const u64 u1 = (u0 >> 32) + (x1 & 0xffffffff) + (x0 >> 32);
const u64 u2 = (u1 >> 32) + (x2 & 0xffffffff) + (x1 >> 32);
const u64 u3 = (u2 >> 32) + (x3 & 0xffffffff) + (x2 >> 32);
const u64 u4 = (u3 >> 32) + (u5 & 3);
// Update the hash
ctx->h[0] = u0 & 0xffffffff; // u0 <= 1_9ffffff0
ctx->h[1] = u1 & 0xffffffff; // u1 <= 1_97ffffe0
ctx->h[2] = u2 & 0xffffffff; // u2 <= 1_8fffffe2
ctx->h[3] = u3 & 0xffffffff; // u3 <= 1_87ffffe4
ctx->h[4] = (u32)u4; // u4 <= 4
}
// (re-)initializes the input counter and input buffer
static void poly_clear_c(crypto_poly1305_ctx *ctx)
{
ctx->c[0] = 0;
ctx->c[1] = 0;
ctx->c[2] = 0;
ctx->c[3] = 0;
ctx->c_idx = 0;
}
static void poly_take_input(crypto_poly1305_ctx *ctx, u8 input)
{
size_t word = ctx->c_idx >> 2;
size_t byte = ctx->c_idx & 3;
ctx->c[word] |= (u32)input << (byte * 8);
ctx->c_idx++;
}
static void poly_update(crypto_poly1305_ctx *ctx,
const u8 *message, size_t message_size)
{
FOR (i, 0, message_size) {
poly_take_input(ctx, message[i]);
if (ctx->c_idx == 16) {
poly_block(ctx);
poly_clear_c(ctx);
}
}
}
void crypto_poly1305_init(crypto_poly1305_ctx *ctx, const u8 key[32])
{
// Initial hash is zero
FOR (i, 0, 5) {
ctx->h[i] = 0;
}
// add 2^130 to every input block
ctx->c[4] = 1;
poly_clear_c(ctx);
// load r and pad (r has some of its bits cleared)
FOR (i, 0, 1) { ctx->r [0] = load32_le(key ) & 0x0fffffff; }
FOR (i, 1, 4) { ctx->r [i] = load32_le(key + i*4 ) & 0x0ffffffc; }
FOR (i, 0, 4) { ctx->pad[i] = load32_le(key + i*4 + 16); }
}
void crypto_poly1305_update(crypto_poly1305_ctx *ctx,
const u8 *message, size_t message_size)
{
// Align ourselves with block boundaries
size_t align = MIN(ALIGN(ctx->c_idx, 16), message_size);
poly_update(ctx, message, align);
message += align;
message_size -= align;
// Process the message block by block
size_t nb_blocks = message_size >> 4;
FOR (i, 0, nb_blocks) {
ctx->c[0] = load32_le(message + 0);
ctx->c[1] = load32_le(message + 4);
ctx->c[2] = load32_le(message + 8);
ctx->c[3] = load32_le(message + 12);
poly_block(ctx);
message += 16;
}
if (nb_blocks > 0) {
poly_clear_c(ctx);
}
message_size &= 15;
// remaining bytes
poly_update(ctx, message, message_size);
}
void crypto_poly1305_final(crypto_poly1305_ctx *ctx, u8 mac[16])
{
// Process the last block (if any)
if (ctx->c_idx != 0) {
// move the final 1 according to remaining input length
// (We may add less than 2^130 to the last input block)
ctx->c[4] = 0;
poly_take_input(ctx, 1);
// one last hash update
poly_block(ctx);
}
// check if we should subtract 2^130-5 by performing the
// corresponding carry propagation.
const u64 u0 = (u64)5 + ctx->h[0]; // <= 1_00000004
const u64 u1 = (u0 >> 32) + ctx->h[1]; // <= 1_00000000
const u64 u2 = (u1 >> 32) + ctx->h[2]; // <= 1_00000000
const u64 u3 = (u2 >> 32) + ctx->h[3]; // <= 1_00000000
const u64 u4 = (u3 >> 32) + ctx->h[4]; // <= 5
// u4 indicates how many times we should subtract 2^130-5 (0 or 1)
// h + pad, minus 2^130-5 if u4 exceeds 3
const u64 uu0 = (u4 >> 2) * 5 + ctx->h[0] + ctx->pad[0]; // <= 2_00000003
const u64 uu1 = (uu0 >> 32) + ctx->h[1] + ctx->pad[1]; // <= 2_00000000
const u64 uu2 = (uu1 >> 32) + ctx->h[2] + ctx->pad[2]; // <= 2_00000000
const u64 uu3 = (uu2 >> 32) + ctx->h[3] + ctx->pad[3]; // <= 2_00000000
store32_le(mac , (u32)uu0);
store32_le(mac + 4, (u32)uu1);
store32_le(mac + 8, (u32)uu2);
store32_le(mac + 12, (u32)uu3);
WIPE_CTX(ctx);
}
void crypto_poly1305(u8 mac[16], const u8 *message,
size_t message_size, const u8 key[32])
{
crypto_poly1305_ctx ctx;
crypto_poly1305_init (&ctx, key);
crypto_poly1305_update(&ctx, message, message_size);
crypto_poly1305_final (&ctx, mac);
}
////////////////
/// Blake2 b ///
////////////////
static const u64 iv[8] = {
0x6a09e667f3bcc908, 0xbb67ae8584caa73b,
0x3c6ef372fe94f82b, 0xa54ff53a5f1d36f1,
0x510e527fade682d1, 0x9b05688c2b3e6c1f,
0x1f83d9abfb41bd6b, 0x5be0cd19137e2179,
};
// increment the input offset
static void blake2b_incr(crypto_blake2b_ctx *ctx)
{
u64 *x = ctx->input_offset;
size_t y = ctx->input_idx;
x[0] += y;
if (x[0] < y) {
x[1]++;
}
}
static void blake2b_compress(crypto_blake2b_ctx *ctx, int is_last_block)
{
static const u8 sigma[12][16] = {
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
{ 14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3 },
{ 11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4 },
{ 7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8 },
{ 9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13 },
{ 2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9 },
{ 12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11 },
{ 13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10 },
{ 6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5 },
{ 10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0 },
};
// init work vector
u64 v0 = ctx->hash[0]; u64 v8 = iv[0];
u64 v1 = ctx->hash[1]; u64 v9 = iv[1];
u64 v2 = ctx->hash[2]; u64 v10 = iv[2];
u64 v3 = ctx->hash[3]; u64 v11 = iv[3];
u64 v4 = ctx->hash[4]; u64 v12 = iv[4] ^ ctx->input_offset[0];
u64 v5 = ctx->hash[5]; u64 v13 = iv[5] ^ ctx->input_offset[1];
u64 v6 = ctx->hash[6]; u64 v14 = iv[6] ^ is_last_block;
u64 v7 = ctx->hash[7]; u64 v15 = iv[7];
// mangle work vector
uint64_t *input = ctx->input;
#define BLAKE2_G(v, a, b, c, d, x, y) \
v##a += v##b + x; v##d = rotr64(v##d ^ v##a, 32); \
v##c += v##d; v##b = rotr64(v##b ^ v##c, 24); \
v##a += v##b + y; v##d = rotr64(v##d ^ v##a, 16); \
v##c += v##d; v##b = rotr64(v##b ^ v##c, 63);
#define BLAKE2_ROUND(i) \
BLAKE2_G(v, 0, 4, 8, 12, input[sigma[i][ 0]], input[sigma[i][ 1]]);\
BLAKE2_G(v, 1, 5, 9, 13, input[sigma[i][ 2]], input[sigma[i][ 3]]);\
BLAKE2_G(v, 2, 6, 10, 14, input[sigma[i][ 4]], input[sigma[i][ 5]]);\
BLAKE2_G(v, 3, 7, 11, 15, input[sigma[i][ 6]], input[sigma[i][ 7]]);\
BLAKE2_G(v, 0, 5, 10, 15, input[sigma[i][ 8]], input[sigma[i][ 9]]);\
BLAKE2_G(v, 1, 6, 11, 12, input[sigma[i][10]], input[sigma[i][11]]);\
BLAKE2_G(v, 2, 7, 8, 13, input[sigma[i][12]], input[sigma[i][13]]);\
BLAKE2_G(v, 3, 4, 9, 14, input[sigma[i][14]], input[sigma[i][15]])
BLAKE2_ROUND(0); BLAKE2_ROUND(1); BLAKE2_ROUND(2); BLAKE2_ROUND(3);
BLAKE2_ROUND(4); BLAKE2_ROUND(5); BLAKE2_ROUND(6); BLAKE2_ROUND(7);
BLAKE2_ROUND(8); BLAKE2_ROUND(9); BLAKE2_ROUND(0); BLAKE2_ROUND(1);
// update hash
ctx->hash[0] ^= v0 ^ v8;
ctx->hash[1] ^= v1 ^ v9;
ctx->hash[2] ^= v2 ^ v10;
ctx->hash[3] ^= v3 ^ v11;
ctx->hash[4] ^= v4 ^ v12;
ctx->hash[5] ^= v5 ^ v13;
ctx->hash[6] ^= v6 ^ v14;
ctx->hash[7] ^= v7 ^ v15;
}
static void blake2b_set_input(crypto_blake2b_ctx *ctx, u8 input, size_t index)
{
if (index == 0) {
FOR (i, 0, 16) {
ctx->input[i] = 0;
}
}
size_t word = index >> 3;
size_t byte = index & 7;
ctx->input[word] |= (u64)input << (byte << 3);
}
static void blake2b_end_block(crypto_blake2b_ctx *ctx)
{
if (ctx->input_idx == 128) { // If buffer is full,
blake2b_incr(ctx); // update the input offset
blake2b_compress(ctx, 0); // and compress the (not last) block
ctx->input_idx = 0;
}
}
static void blake2b_update(crypto_blake2b_ctx *ctx,
const u8 *message, size_t message_size)
{
FOR (i, 0, message_size) {
blake2b_end_block(ctx);
blake2b_set_input(ctx, message[i], ctx->input_idx);
ctx->input_idx++;
}
}
void crypto_blake2b_general_init(crypto_blake2b_ctx *ctx, size_t hash_size,
const u8 *key, size_t key_size)
{
// initial hash
FOR (i, 0, 8) {
ctx->hash[i] = iv[i];
}
ctx->hash[0] ^= 0x01010000 ^ (key_size << 8) ^ hash_size;
ctx->input_offset[0] = 0; // begining of the input, no offset
ctx->input_offset[1] = 0; // begining of the input, no offset
ctx->hash_size = hash_size; // remember the hash size we want
ctx->input_idx = 0;
// if there is a key, the first block is that key (padded with zeroes)
if (key_size > 0) {
crypto_blake2b_update(ctx, key , key_size);
crypto_blake2b_update(ctx, zero, 128 - key_size);
}
}
void crypto_blake2b_init(crypto_blake2b_ctx *ctx)
{
crypto_blake2b_general_init(ctx, 64, 0, 0);
}
void crypto_blake2b_update(crypto_blake2b_ctx *ctx,
const u8 *message, size_t message_size)
{
// Align ourselves with block boundaries
size_t align = MIN(ALIGN(ctx->input_idx, 128), message_size);
blake2b_update(ctx, message, align);
message += align;
message_size -= align;
// Process the message block by block
FOR (i, 0, message_size >> 7) { // number of blocks
blake2b_end_block(ctx);
FOR (j, 0, 16) {
ctx->input[j] = load64_le(message + j*8);
}
message += 128;
ctx->input_idx = 128;
}
message_size &= 127;
// remaining bytes
blake2b_update(ctx, message, message_size);
}
void crypto_blake2b_final(crypto_blake2b_ctx *ctx, u8 *hash)
{
// Pad the end of the block with zeroes
FOR (i, ctx->input_idx, 128) {
blake2b_set_input(ctx, 0, i);
}
blake2b_incr(ctx); // update the input offset
blake2b_compress(ctx, -1); // compress the last block
size_t nb_words = ctx->hash_size >> 3;
FOR (i, 0, nb_words) {
store64_le(hash + i*8, ctx->hash[i]);
}
FOR (i, nb_words * 8, ctx->hash_size) {
hash[i] = (ctx->hash[i >> 3] >> (8 * (i & 7))) & 0xff;
}
WIPE_CTX(ctx);
}
void crypto_blake2b_general(u8 *hash , size_t hash_size,
const u8 *key , size_t key_size,
const u8 *message, size_t message_size)
{
crypto_blake2b_ctx ctx;
crypto_blake2b_general_init(&ctx, hash_size, key, key_size);
crypto_blake2b_update(&ctx, message, message_size);
crypto_blake2b_final(&ctx, hash);
}
void crypto_blake2b(u8 hash[64], const u8 *message, size_t message_size)
{
crypto_blake2b_general(hash, 64, 0, 0, message, message_size);
}
////////////////
/// Argon2 i ///
////////////////
// references to R, Z, Q etc. come from the spec
// Argon2 operates on 1024 byte blocks.
typedef struct { u64 a[128]; } block;
static void wipe_block(block *b)
{
volatile u64* a = b->a;
FOR (i, 0, 128) {
a[i] = 0;
}
}
// updates a blake2 hash with a 32 bit word, little endian.
static void blake_update_32(crypto_blake2b_ctx *ctx, u32 input)
{
u8 buf[4];
store32_le(buf, input);
crypto_blake2b_update(ctx, buf, 4);
WIPE_BUFFER(buf);
}
static void load_block(block *b, const u8 bytes[1024])
{
FOR (i, 0, 128) {
b->a[i] = load64_le(bytes + i*8);
}
}
static void store_block(u8 bytes[1024], const block *b)
{
FOR (i, 0, 128) {
store64_le(bytes + i*8, b->a[i]);
}
}
static void copy_block(block *o,const block*in){FOR(i,0,128)o->a[i] = in->a[i];}
static void xor_block(block *o,const block*in){FOR(i,0,128)o->a[i]^= in->a[i];}
// Hash with a virtually unlimited digest size.
// Doesn't extract more entropy than the base hash function.
// Mainly used for filling a whole kilobyte block with pseudo-random bytes.
// (One could use a stream cipher with a seed hash as the key, but
// this would introduce another dependency —and point of failure.)
static void extended_hash(u8 *digest, u32 digest_size,
const u8 *input , u32 input_size)
{
crypto_blake2b_ctx ctx;
crypto_blake2b_general_init(&ctx, MIN(digest_size, 64), 0, 0);
blake_update_32 (&ctx, digest_size);
crypto_blake2b_update (&ctx, input, input_size);
crypto_blake2b_final (&ctx, digest);
if (digest_size > 64) {
// the conversion to u64 avoids integer overflow on
// ludicrously big hash sizes.
u32 r = (((u64)digest_size + 31) >> 5) - 2;
u32 i = 1;
u32 in = 0;
u32 out = 32;
while (i < r) {
// Input and output overlap. This is intentional
crypto_blake2b(digest + out, digest + in, 64);
i += 1;
in += 32;
out += 32;
}
crypto_blake2b_general(digest + out, digest_size - (32 * r),
0, 0, // no key
digest + in , 64);
}
}
#define LSB(x) ((x) & 0xffffffff)
#define G(a, b, c, d) \
a += b + 2 * LSB(a) * LSB(b); d ^= a; d = rotr64(d, 32); \
c += d + 2 * LSB(c) * LSB(d); b ^= c; b = rotr64(b, 24); \
a += b + 2 * LSB(a) * LSB(b); d ^= a; d = rotr64(d, 16); \
c += d + 2 * LSB(c) * LSB(d); b ^= c; b = rotr64(b, 63)
#define ROUND(v0, v1, v2, v3, v4, v5, v6, v7, \
v8, v9, v10, v11, v12, v13, v14, v15) \
G(v0, v4, v8, v12); G(v1, v5, v9, v13); \
G(v2, v6, v10, v14); G(v3, v7, v11, v15); \
G(v0, v5, v10, v15); G(v1, v6, v11, v12); \
G(v2, v7, v8, v13); G(v3, v4, v9, v14)
// Core of the compression function G. Computes Z from R in place.
static void g_rounds(block *work_block)
{
// column rounds (work_block = Q)
for (int i = 0; i < 128; i += 16) {
ROUND(work_block->a[i ], work_block->a[i + 1],
work_block->a[i + 2], work_block->a[i + 3],
work_block->a[i + 4], work_block->a[i + 5],
work_block->a[i + 6], work_block->a[i + 7],
work_block->a[i + 8], work_block->a[i + 9],
work_block->a[i + 10], work_block->a[i + 11],
work_block->a[i + 12], work_block->a[i + 13],
work_block->a[i + 14], work_block->a[i + 15]);
}
// row rounds (work_block = Z)
for (int i = 0; i < 16; i += 2) {
ROUND(work_block->a[i ], work_block->a[i + 1],
work_block->a[i + 16], work_block->a[i + 17],
work_block->a[i + 32], work_block->a[i + 33],
work_block->a[i + 48], work_block->a[i + 49],
work_block->a[i + 64], work_block->a[i + 65],
work_block->a[i + 80], work_block->a[i + 81],
work_block->a[i + 96], work_block->a[i + 97],
work_block->a[i + 112], work_block->a[i + 113]);
}
}
// The compression function G (copy version for the first pass)
static void g_copy(block *result, const block *x, const block *y, block* tmp)
{
copy_block(tmp , x ); // tmp = X
xor_block (tmp , y ); // tmp = X ^ Y = R
copy_block(result, tmp); // result = R (only difference with g_xor)
g_rounds (tmp); // tmp = Z
xor_block (result, tmp); // result = R ^ Z
}
// The compression function G (xor version for subsequent passes)
static void g_xor(block *result, const block *x, const block *y, block *tmp)
{
copy_block(tmp , x ); // tmp = X
xor_block (tmp , y ); // tmp = X ^ Y = R
xor_block (result, tmp); // result = R ^ old (only difference with g_copy)
g_rounds (tmp); // tmp = Z
xor_block (result, tmp); // result = R ^ old ^ Z
}
// unary version of the compression function.
// The missing argument is implied zero.
// Does the transformation in place.
static void unary_g(block *work_block)
{
// work_block == R
block tmp;
copy_block(&tmp, work_block); // tmp = R
g_rounds(work_block); // work_block = Z
xor_block(work_block, &tmp); // work_block = Z ^ R
wipe_block(&tmp);
}
// Argon2i uses a kind of stream cipher to determine which reference
// block it will take to synthesise the next block. This context hold
// that stream's state. (It's very similar to Chacha20. The block b
// is anologous to Chacha's own pool)
typedef struct {
block b;
u32 pass_number;
u32 slice_number;
u32 nb_blocks;
u32 nb_iterations;
u32 ctr;
u32 offset;
} gidx_ctx;
// The block in the context will determine array indices. To avoid
// timing attacks, it only depends on public information. No looking
// at a previous block to seed the next. This makes offline attacks
// easier, but timing attacks are the bigger threat in many settings.
static void gidx_refresh(gidx_ctx *ctx)
{
// seed the begining of the block...
ctx->b.a[0] = ctx->pass_number;
ctx->b.a[1] = 0; // lane number (we have only one)
ctx->b.a[2] = ctx->slice_number;
ctx->b.a[3] = ctx->nb_blocks;
ctx->b.a[4] = ctx->nb_iterations;
ctx->b.a[5] = 1; // type: Argon2i
ctx->b.a[6] = ctx->ctr;
FOR (i, 7, 128) { ctx->b.a[i] = 0; } // ...then zero the rest out
// Shuffle the block thus: ctx->b = G((G(ctx->b, zero)), zero)
// (G "square" function), to get cheap pseudo-random numbers.
unary_g(&ctx->b);
unary_g(&ctx->b);
}
static void gidx_init(gidx_ctx *ctx,
u32 pass_number, u32 slice_number,
u32 nb_blocks, u32 nb_iterations)
{
ctx->pass_number = pass_number;
ctx->slice_number = slice_number;
ctx->nb_blocks = nb_blocks;
ctx->nb_iterations = nb_iterations;
ctx->ctr = 0;
// Offset from the begining of the segment. For the first slice
// of the first pass, we start at the *third* block, so the offset
// starts at 2, not 0.
if (pass_number != 0 || slice_number != 0) {
ctx->offset = 0;
} else {
ctx->offset = 2;
ctx->ctr++; // Compensates for missed lazy creation
gidx_refresh(ctx); // at the start of gidx_next()
}
}
static u32 gidx_next(gidx_ctx *ctx)
{
// lazily creates the offset block we need
if ((ctx->offset & 127) == 0) {
ctx->ctr++;
gidx_refresh(ctx);
}
u32 index = ctx->offset & 127; // save index for current call
u32 offset = ctx->offset; // save offset for current call
ctx->offset++; // update offset for next call
// Computes the area size.
// Pass 0 : all already finished segments plus already constructed
// blocks in this segment
// Pass 1+: 3 last segments plus already constructed
// blocks in this segment. THE SPEC SUGGESTS OTHERWISE.
// I CONFORM TO THE REFERENCE IMPLEMENTATION.
int first_pass = ctx->pass_number == 0;
u32 slice_size = ctx->nb_blocks >> 2;
u32 nb_segments = first_pass ? ctx->slice_number : 3;
u32 area_size = nb_segments * slice_size + offset - 1;
// Computes the starting position of the reference area.
// CONTRARY TO WHAT THE SPEC SUGGESTS, IT STARTS AT THE
// NEXT SEGMENT, NOT THE NEXT BLOCK.
u32 next_slice = ((ctx->slice_number + 1) & 3) * slice_size;
u32 start_pos = first_pass ? 0 : next_slice;
// Generate offset from J1 (no need for J2, there's only one lane)
u64 j1 = ctx->b.a[index] & 0xffffffff; // pseudo-random number
u64 x = (j1 * j1) >> 32;
u64 y = (area_size * x) >> 32;
u64 z = (area_size - 1) - y;
return (start_pos + z) % ctx->nb_blocks;
}
// Main algorithm
void crypto_argon2i_general(u8 *hash, u32 hash_size,
void *work_area, u32 nb_blocks,
u32 nb_iterations,
const u8 *password, u32 password_size,
const u8 *salt, u32 salt_size,
const u8 *key, u32 key_size,
const u8 *ad, u32 ad_size)
{
// work area seen as blocks (must be suitably aligned)
block *blocks = (block*)work_area;
{
crypto_blake2b_ctx ctx;
crypto_blake2b_init(&ctx);
blake_update_32 (&ctx, 1 ); // p: number of threads
blake_update_32 (&ctx, hash_size );
blake_update_32 (&ctx, nb_blocks );
blake_update_32 (&ctx, nb_iterations);
blake_update_32 (&ctx, 0x13 ); // v: version number
blake_update_32 (&ctx, 1 ); // y: Argon2i
blake_update_32 (&ctx, password_size);
crypto_blake2b_update(&ctx, password, password_size);
blake_update_32 (&ctx, salt_size);
crypto_blake2b_update(&ctx, salt, salt_size);
blake_update_32 (&ctx, key_size);
crypto_blake2b_update(&ctx, key, key_size);
blake_update_32 (&ctx, ad_size);
crypto_blake2b_update(&ctx, ad, ad_size);
u8 initial_hash[72]; // 64 bytes plus 2 words for future hashes
crypto_blake2b_final(&ctx, initial_hash);
// fill first 2 blocks
block tmp_block;
u8 hash_area[1024];
store32_le(initial_hash + 64, 0); // first additional word
store32_le(initial_hash + 68, 0); // second additional word
extended_hash(hash_area, 1024, initial_hash, 72);
load_block(&tmp_block, hash_area);
copy_block(blocks, &tmp_block);
store32_le(initial_hash + 64, 1); // slight modification
extended_hash(hash_area, 1024, initial_hash, 72);
load_block(&tmp_block, hash_area);
copy_block(blocks + 1, &tmp_block);
WIPE_BUFFER(initial_hash);
WIPE_BUFFER(hash_area);
wipe_block(&tmp_block);
}
// Actual number of blocks
nb_blocks -= nb_blocks & 3; // round down to 4 p (p == 1 thread)
const u32 segment_size = nb_blocks >> 2;
// fill (then re-fill) the rest of the blocks
block tmp;
gidx_ctx ctx;
FOR (pass_number, 0, nb_iterations) {
int first_pass = pass_number == 0;
FOR (segment, 0, 4) {
gidx_init(&ctx, (u32)pass_number, (u32)segment,
nb_blocks, nb_iterations);
// On the first segment of the first pass,
// blocks 0 and 1 are already filled.
// We use the offset to skip them.
u32 start_offset = first_pass && segment == 0 ? 2 : 0;
u32 segment_start = (u32)segment * segment_size + start_offset;
u32 segment_end = ((u32)segment + 1) * segment_size;
FOR (current_block, segment_start, segment_end) {
u32 reference_block = gidx_next(&ctx);
u32 previous_block = current_block == 0
? nb_blocks - 1
: (u32)current_block - 1;
block *c = blocks + current_block;
block *p = blocks + previous_block;
block *r = blocks + reference_block;
if (first_pass) { g_copy(c, p, r, &tmp); }
else { g_xor (c, p, r, &tmp); }
}
}
}
wipe_block(&ctx.b);
wipe_block(&tmp);
// hash the very last block with H' into the output hash
u8 final_block[1024];
store_block(final_block, blocks + (nb_blocks - 1));
extended_hash(hash, hash_size, final_block, 1024);
WIPE_BUFFER(final_block);
// wipe work area
volatile u64 *p = (u64*)work_area;
FOR (i, 0, 128 * nb_blocks) {
p[i] = 0;
}
}
void crypto_argon2i(u8 *hash, u32 hash_size,
void *work_area, u32 nb_blocks,
u32 nb_iterations,
const u8 *password, u32 password_size,
const u8 *salt, u32 salt_size)
{
crypto_argon2i_general(hash, hash_size,
work_area, nb_blocks, nb_iterations,
password, password_size,
salt , salt_size,
0, 0, 0, 0);
}
////////////////////////////////////
/// Arithmetic modulo 2^255 - 19 ///
////////////////////////////////////
// Taken from Supercop's ref10 implementation.
// A bit bigger than TweetNaCl, over 4 times faster.
// field element
typedef i32 fe[10];
static void fe_0(fe h) { FOR(i, 0, 10) h[i] = 0; }
static void fe_1(fe h) { h[0] = 1; FOR(i, 1, 10) h[i] = 0; }
static void fe_copy(fe h,const fe f ){FOR(i,0,10) h[i] = f[i]; }
static void fe_neg (fe h,const fe f ){FOR(i,0,10) h[i] = -f[i]; }
static void fe_add (fe h,const fe f,const fe g){FOR(i,0,10) h[i] = f[i] + g[i];}
static void fe_sub (fe h,const fe f,const fe g){FOR(i,0,10) h[i] = f[i] - g[i];}
static void fe_cswap(fe f, fe g, int b)
{
FOR (i, 0, 10) {
i32 x = (f[i] ^ g[i]) & -b;
f[i] = f[i] ^ x;
g[i] = g[i] ^ x;
}
}
static void fe_ccopy(fe f, const fe g, int b)
{
FOR (i, 0, 10) {
i32 x = (f[i] ^ g[i]) & -b;
f[i] = f[i] ^ x;
}
}
#define FE_CARRY \
i64 c0, c1, c2, c3, c4, c5, c6, c7, c8, c9; \
c9 = (t9 + (i64) (1<<24)) >> 25; t0 += c9 * 19; t9 -= c9 * (1 << 25); \
c1 = (t1 + (i64) (1<<24)) >> 25; t2 += c1; t1 -= c1 * (1 << 25); \
c3 = (t3 + (i64) (1<<24)) >> 25; t4 += c3; t3 -= c3 * (1 << 25); \
c5 = (t5 + (i64) (1<<24)) >> 25; t6 += c5; t5 -= c5 * (1 << 25); \
c7 = (t7 + (i64) (1<<24)) >> 25; t8 += c7; t7 -= c7 * (1 << 25); \
c0 = (t0 + (i64) (1<<25)) >> 26; t1 += c0; t0 -= c0 * (1 << 26); \
c2 = (t2 + (i64) (1<<25)) >> 26; t3 += c2; t2 -= c2 * (1 << 26); \
c4 = (t4 + (i64) (1<<25)) >> 26; t5 += c4; t4 -= c4 * (1 << 26); \
c6 = (t6 + (i64) (1<<25)) >> 26; t7 += c6; t6 -= c6 * (1 << 26); \
c8 = (t8 + (i64) (1<<25)) >> 26; t9 += c8; t8 -= c8 * (1 << 26); \
h[0]=(i32)t0; h[1]=(i32)t1; h[2]=(i32)t2; h[3]=(i32)t3; h[4]=(i32)t4; \
h[5]=(i32)t5; h[6]=(i32)t6; h[7]=(i32)t7; h[8]=(i32)t8; h[9]=(i32)t9
static void fe_frombytes(fe h, const u8 s[32])
{
i64 t0 = load32_le(s);
i64 t1 = load24_le(s + 4) << 6;
i64 t2 = load24_le(s + 7) << 5;
i64 t3 = load24_le(s + 10) << 3;
i64 t4 = load24_le(s + 13) << 2;
i64 t5 = load32_le(s + 16);
i64 t6 = load24_le(s + 20) << 7;
i64 t7 = load24_le(s + 23) << 5;
i64 t8 = load24_le(s + 26) << 4;
i64 t9 = (load24_le(s + 29) & 8388607) << 2;
FE_CARRY;
}
static void fe_mul_small(fe h, const fe f, i32 g)
{
i64 t0 = f[0] * (i64) g; i64 t1 = f[1] * (i64) g;
i64 t2 = f[2] * (i64) g; i64 t3 = f[3] * (i64) g;
i64 t4 = f[4] * (i64) g; i64 t5 = f[5] * (i64) g;
i64 t6 = f[6] * (i64) g; i64 t7 = f[7] * (i64) g;
i64 t8 = f[8] * (i64) g; i64 t9 = f[9] * (i64) g;
FE_CARRY;
}
static void fe_mul121666(fe h, const fe f) { fe_mul_small(h, f, 121666); }
static void fe_mul(fe h, const fe f, const fe g)
{
// Everything is unrolled and put in temporary variables.
// We could roll the loop, but that would make curve25519 twice as slow.
i32 f0 = f[0]; i32 f1 = f[1]; i32 f2 = f[2]; i32 f3 = f[3]; i32 f4 = f[4];
i32 f5 = f[5]; i32 f6 = f[6]; i32 f7 = f[7]; i32 f8 = f[8]; i32 f9 = f[9];
i32 g0 = g[0]; i32 g1 = g[1]; i32 g2 = g[2]; i32 g3 = g[3]; i32 g4 = g[4];
i32 g5 = g[5]; i32 g6 = g[6]; i32 g7 = g[7]; i32 g8 = g[8]; i32 g9 = g[9];
i32 F1 = f1*2; i32 F3 = f3*2; i32 F5 = f5*2; i32 F7 = f7*2; i32 F9 = f9*2;
i32 G1 = g1*19; i32 G2 = g2*19; i32 G3 = g3*19;
i32 G4 = g4*19; i32 G5 = g5*19; i32 G6 = g6*19;
i32 G7 = g7*19; i32 G8 = g8*19; i32 G9 = g9*19;
i64 h0 = f0*(i64)g0 + F1*(i64)G9 + f2*(i64)G8 + F3*(i64)G7 + f4*(i64)G6
+ F5*(i64)G5 + f6*(i64)G4 + F7*(i64)G3 + f8*(i64)G2 + F9*(i64)G1;
i64 h1 = f0*(i64)g1 + f1*(i64)g0 + f2*(i64)G9 + f3*(i64)G8 + f4*(i64)G7
+ f5*(i64)G6 + f6*(i64)G5 + f7*(i64)G4 + f8*(i64)G3 + f9*(i64)G2;
i64 h2 = f0*(i64)g2 + F1*(i64)g1 + f2*(i64)g0 + F3*(i64)G9 + f4*(i64)G8
+ F5*(i64)G7 + f6*(i64)G6 + F7*(i64)G5 + f8*(i64)G4 + F9*(i64)G3;
i64 h3 = f0*(i64)g3 + f1*(i64)g2 + f2*(i64)g1 + f3*(i64)g0 + f4*(i64)G9
+ f5*(i64)G8 + f6*(i64)G7 + f7*(i64)G6 + f8*(i64)G5 + f9*(i64)G4;
i64 h4 = f0*(i64)g4 + F1*(i64)g3 + f2*(i64)g2 + F3*(i64)g1 + f4*(i64)g0
+ F5*(i64)G9 + f6*(i64)G8 + F7*(i64)G7 + f8*(i64)G6 + F9*(i64)G5;
i64 h5 = f0*(i64)g5 + f1*(i64)g4 + f2*(i64)g3 + f3*(i64)g2 + f4*(i64)g1
+ f5*(i64)g0 + f6*(i64)G9 + f7*(i64)G8 + f8*(i64)G7 + f9*(i64)G6;
i64 h6 = f0*(i64)g6 + F1*(i64)g5 + f2*(i64)g4 + F3*(i64)g3 + f4*(i64)g2
+ F5*(i64)g1 + f6*(i64)g0 + F7*(i64)G9 + f8*(i64)G8 + F9*(i64)G7;
i64 h7 = f0*(i64)g7 + f1*(i64)g6 + f2*(i64)g5 + f3*(i64)g4 + f4*(i64)g3
+ f5*(i64)g2 + f6*(i64)g1 + f7*(i64)g0 + f8*(i64)G9 + f9*(i64)G8;
i64 h8 = f0*(i64)g8 + F1*(i64)g7 + f2*(i64)g6 + F3*(i64)g5 + f4*(i64)g4
+ F5*(i64)g3 + f6*(i64)g2 + F7*(i64)g1 + f8*(i64)g0 + F9*(i64)G9;
i64 h9 = f0*(i64)g9 + f1*(i64)g8 + f2*(i64)g7 + f3*(i64)g6 + f4*(i64)g5
+ f5*(i64)g4 + f6*(i64)g3 + f7*(i64)g2 + f8*(i64)g1 + f9*(i64)g0;
#define CARRY \
i64 c0, c1, c2, c3, c4, c5, c6, c7, c8, c9; \
c0 = (h0 + (i64) (1<<25)) >> 26; h1 += c0; h0 -= c0 * (1 << 26); \
c4 = (h4 + (i64) (1<<25)) >> 26; h5 += c4; h4 -= c4 * (1 << 26); \
c1 = (h1 + (i64) (1<<24)) >> 25; h2 += c1; h1 -= c1 * (1 << 25); \
c5 = (h5 + (i64) (1<<24)) >> 25; h6 += c5; h5 -= c5 * (1 << 25); \
c2 = (h2 + (i64) (1<<25)) >> 26; h3 += c2; h2 -= c2 * (1 << 26); \
c6 = (h6 + (i64) (1<<25)) >> 26; h7 += c6; h6 -= c6 * (1 << 26); \
c3 = (h3 + (i64) (1<<24)) >> 25; h4 += c3; h3 -= c3 * (1 << 25); \
c7 = (h7 + (i64) (1<<24)) >> 25; h8 += c7; h7 -= c7 * (1 << 25); \
c4 = (h4 + (i64) (1<<25)) >> 26; h5 += c4; h4 -= c4 * (1 << 26); \
c8 = (h8 + (i64) (1<<25)) >> 26; h9 += c8; h8 -= c8 * (1 << 26); \
c9 = (h9 + (i64) (1<<24)) >> 25; h0 += c9 * 19; h9 -= c9 * (1 << 25); \
c0 = (h0 + (i64) (1<<25)) >> 26; h1 += c0; h0 -= c0 * (1 << 26); \
h[0]=(i32)h0; h[1]=(i32)h1; h[2]=(i32)h2; h[3]=(i32)h3; h[4]=(i32)h4; \
h[5]=(i32)h5; h[6]=(i32)h6; h[7]=(i32)h7; h[8]=(i32)h8; h[9]=(i32)h9; \
CARRY;
}
// we could use fe_mul() for this, but this is significantly faster
static void fe_sq(fe h, const fe f)
{
i32 f0 = f[0]; i32 f1 = f[1]; i32 f2 = f[2]; i32 f3 = f[3]; i32 f4 = f[4];
i32 f5 = f[5]; i32 f6 = f[6]; i32 f7 = f[7]; i32 f8 = f[8]; i32 f9 = f[9];
i32 f0_2 = f0*2; i32 f1_2 = f1*2; i32 f2_2 = f2*2; i32 f3_2 = f3*2;
i32 f4_2 = f4*2; i32 f5_2 = f5*2; i32 f6_2 = f6*2; i32 f7_2 = f7*2;
i32 f5_38 = f5*38; i32 f6_19 = f6*19; i32 f7_38 = f7*38;
i32 f8_19 = f8*19; i32 f9_38 = f9*38;
i64 h0 = f0 *(i64)f0 + f1_2*(i64)f9_38 + f2_2*(i64)f8_19
+ f3_2*(i64)f7_38 + f4_2*(i64)f6_19 + f5 *(i64)f5_38;
i64 h1 = f0_2*(i64)f1 + f2 *(i64)f9_38 + f3_2*(i64)f8_19
+ f4 *(i64)f7_38 + f5_2*(i64)f6_19;
i64 h2 = f0_2*(i64)f2 + f1_2*(i64)f1 + f3_2*(i64)f9_38
+ f4_2*(i64)f8_19 + f5_2*(i64)f7_38 + f6 *(i64)f6_19;
i64 h3 = f0_2*(i64)f3 + f1_2*(i64)f2 + f4 *(i64)f9_38
+ f5_2*(i64)f8_19 + f6 *(i64)f7_38;
i64 h4 = f0_2*(i64)f4 + f1_2*(i64)f3_2 + f2 *(i64)f2
+ f5_2*(i64)f9_38 + f6_2*(i64)f8_19 + f7 *(i64)f7_38;
i64 h5 = f0_2*(i64)f5 + f1_2*(i64)f4 + f2_2*(i64)f3
+ f6 *(i64)f9_38 + f7_2*(i64)f8_19;
i64 h6 = f0_2*(i64)f6 + f1_2*(i64)f5_2 + f2_2*(i64)f4
+ f3_2*(i64)f3 + f7_2*(i64)f9_38 + f8 *(i64)f8_19;
i64 h7 = f0_2*(i64)f7 + f1_2*(i64)f6 + f2_2*(i64)f5
+ f3_2*(i64)f4 + f8 *(i64)f9_38;
i64 h8 = f0_2*(i64)f8 + f1_2*(i64)f7_2 + f2_2*(i64)f6
+ f3_2*(i64)f5_2 + f4 *(i64)f4 + f9 *(i64)f9_38;
i64 h9 = f0_2*(i64)f9 + f1_2*(i64)f8 + f2_2*(i64)f7
+ f3_2*(i64)f6 + f4 *(i64)f5_2;
CARRY;
}
static void fe_sq2(fe h, const fe f)
{
fe_sq(h, f);
fe_mul_small(h, h, 2);
}
// This could be simplified, but it would be slower
static void fe_invert(fe out, const fe z)
{
fe t0, t1, t2, t3;
fe_sq(t0, z );
fe_sq(t1, t0);
fe_sq(t1, t1);
fe_mul(t1, z, t1);
fe_mul(t0, t0, t1);
fe_sq(t2, t0); fe_mul(t1 , t1, t2);
fe_sq(t2, t1); FOR (i, 1, 5) fe_sq(t2, t2); fe_mul(t1 , t2, t1);
fe_sq(t2, t1); FOR (i, 1, 10) fe_sq(t2, t2); fe_mul(t2 , t2, t1);
fe_sq(t3, t2); FOR (i, 1, 20) fe_sq(t3, t3); fe_mul(t2 , t3, t2);
fe_sq(t2, t2); FOR (i, 1, 10) fe_sq(t2, t2); fe_mul(t1 , t2, t1);
fe_sq(t2, t1); FOR (i, 1, 50) fe_sq(t2, t2); fe_mul(t2 , t2, t1);
fe_sq(t3, t2); FOR (i, 1, 100) fe_sq(t3, t3); fe_mul(t2 , t3, t2);
fe_sq(t2, t2); FOR (i, 1, 50) fe_sq(t2, t2); fe_mul(t1 , t2, t1);
fe_sq(t1, t1); FOR (i, 1, 5) fe_sq(t1, t1); fe_mul(out, t1, t0);
WIPE_BUFFER(t0);
WIPE_BUFFER(t1);
WIPE_BUFFER(t2);
WIPE_BUFFER(t3);
}
// This could be simplified, but it would be slower
static void fe_pow22523(fe out, const fe z)
{
fe t0, t1, t2;
fe_sq(t0, z);
fe_sq(t1,t0); fe_sq(t1, t1); fe_mul(t1, z, t1);
fe_mul(t0, t0, t1);
fe_sq(t0, t0); fe_mul(t0, t1, t0);
fe_sq(t1, t0); FOR (i, 1, 5) fe_sq(t1, t1); fe_mul(t0, t1, t0);
fe_sq(t1, t0); FOR (i, 1, 10) fe_sq(t1, t1); fe_mul(t1, t1, t0);
fe_sq(t2, t1); FOR (i, 1, 20) fe_sq(t2, t2); fe_mul(t1, t2, t1);
fe_sq(t1, t1); FOR (i, 1, 10) fe_sq(t1, t1); fe_mul(t0, t1, t0);
fe_sq(t1, t0); FOR (i, 1, 50) fe_sq(t1, t1); fe_mul(t1, t1, t0);
fe_sq(t2, t1); FOR (i, 1, 100) fe_sq(t2, t2); fe_mul(t1, t2, t1);
fe_sq(t1, t1); FOR (i, 1, 50) fe_sq(t1, t1); fe_mul(t0, t1, t0);
fe_sq(t0, t0); FOR (i, 1, 2) fe_sq(t0, t0); fe_mul(out, t0, z);
WIPE_BUFFER(t0);
WIPE_BUFFER(t1);
WIPE_BUFFER(t2);
}
static void fe_tobytes(u8 s[32], const fe h)
{
i32 t[10];
FOR (i, 0, 10) {
t[i] = h[i];
}
i32 q = (19 * t[9] + (((i32) 1) << 24)) >> 25;
FOR (i, 0, 5) {
q += t[2*i ]; q >>= 26;
q += t[2*i+1]; q >>= 25;
}
t[0] += 19 * q;
i32 c0 = t[0] >> 26; t[1] += c0; t[0] -= c0 * (1 << 26);
i32 c1 = t[1] >> 25; t[2] += c1; t[1] -= c1 * (1 << 25);
i32 c2 = t[2] >> 26; t[3] += c2; t[2] -= c2 * (1 << 26);
i32 c3 = t[3] >> 25; t[4] += c3; t[3] -= c3 * (1 << 25);
i32 c4 = t[4] >> 26; t[5] += c4; t[4] -= c4 * (1 << 26);
i32 c5 = t[5] >> 25; t[6] += c5; t[5] -= c5 * (1 << 25);
i32 c6 = t[6] >> 26; t[7] += c6; t[6] -= c6 * (1 << 26);
i32 c7 = t[7] >> 25; t[8] += c7; t[7] -= c7 * (1 << 25);
i32 c8 = t[8] >> 26; t[9] += c8; t[8] -= c8 * (1 << 26);
i32 c9 = t[9] >> 25; t[9] -= c9 * (1 << 25);
store32_le(s + 0, ((u32)t[0] >> 0) | ((u32)t[1] << 26));
store32_le(s + 4, ((u32)t[1] >> 6) | ((u32)t[2] << 19));
store32_le(s + 8, ((u32)t[2] >> 13) | ((u32)t[3] << 13));
store32_le(s + 12, ((u32)t[3] >> 19) | ((u32)t[4] << 6));
store32_le(s + 16, ((u32)t[5] >> 0) | ((u32)t[6] << 25));
store32_le(s + 20, ((u32)t[6] >> 7) | ((u32)t[7] << 19));
store32_le(s + 24, ((u32)t[7] >> 13) | ((u32)t[8] << 12));
store32_le(s + 28, ((u32)t[8] >> 20) | ((u32)t[9] << 6));
WIPE_BUFFER(t);
}
// Parity check. Returns 0 if even, 1 if odd
static int fe_isnegative(const fe f)
{
u8 s[32];
fe_tobytes(s, f);
u8 isneg = s[0] & 1;
WIPE_BUFFER(s);
return isneg;
}
static int fe_isnonzero(const fe f)
{
u8 s[32];
fe_tobytes(s, f);
u8 isnonzero = zerocmp32(s);
WIPE_BUFFER(s);
return isnonzero;
}
///////////////
/// X-25519 /// Taken from Supercop's ref10 implementation.
///////////////
static void trim_scalar(u8 s[32])
{
s[ 0] &= 248;
s[31] &= 127;
s[31] |= 64;
}
static int scalar_bit(const u8 s[32], int i) { return (s[i>>3] >> (i&7)) & 1; }
int crypto_x25519(u8 raw_shared_secret[32],
const u8 your_secret_key [32],
const u8 their_public_key [32])
{
// computes the scalar product
fe x1;
fe_frombytes(x1, their_public_key);
// restrict the possible scalar values
u8 e[32];
FOR (i, 0, 32) {
e[i] = your_secret_key[i];
}
trim_scalar(e);
// computes the actual scalar product (the result is in x2 and z2)
fe x2, z2, x3, z3, t0, t1;
// Montgomery ladder
// In projective coordinates, to avoid divisons: x = X / Z
// We don't care about the y coordinate, it's only 1 bit of information
fe_1(x2); fe_0(z2); // "zero" point
fe_copy(x3, x1); fe_1(z3); // "one" point
int swap = 0;
for (int pos = 254; pos >= 0; --pos) {
// constant time conditional swap before ladder step
int b = scalar_bit(e, pos);
swap ^= b; // xor trick avoids swapping at the end of the loop
fe_cswap(x2, x3, swap);
fe_cswap(z2, z3, swap);
swap = b; // anticipates one last swap after the loop
// Montgomery ladder step: replaces (P2, P3) by (P2*2, P2+P3)
// with differential addition
fe_sub(t0, x3, z3); fe_sub(t1, x2, z2); fe_add(x2, x2, z2);
fe_add(z2, x3, z3); fe_mul(z3, t0, x2); fe_mul(z2, z2, t1);
fe_sq (t0, t1 ); fe_sq (t1, x2 ); fe_add(x3, z3, z2);
fe_sub(z2, z3, z2); fe_mul(x2, t1, t0); fe_sub(t1, t1, t0);
fe_sq (z2, z2 ); fe_mul121666(z3, t1); fe_sq (x3, x3 );
fe_add(t0, t0, z3); fe_mul(z3, x1, z2); fe_mul(z2, t1, t0);
}
// last swap is necessary to compensate for the xor trick
// Note: after this swap, P3 == P2 + P1.
fe_cswap(x2, x3, swap);
fe_cswap(z2, z3, swap);
// normalises the coordinates: x == X / Z
fe_invert(z2, z2);
fe_mul(x2, x2, z2);
fe_tobytes(raw_shared_secret, x2);
WIPE_BUFFER(x1); WIPE_BUFFER(e );
WIPE_BUFFER(x2); WIPE_BUFFER(z2);
WIPE_BUFFER(x3); WIPE_BUFFER(z3);
WIPE_BUFFER(t0); WIPE_BUFFER(t1);
// Returns -1 if the output is all zero
// (happens with some malicious public keys)
return -1 - zerocmp32(raw_shared_secret);
}
void crypto_x25519_public_key(u8 public_key[32],
const u8 secret_key[32])
{
static const u8 base_point[32] = {9};
crypto_x25519(public_key, secret_key, base_point);
}
///////////////
/// Ed25519 ///
///////////////
static const u64 L[32] = { 0xed, 0xd3, 0xf5, 0x5c, 0x1a, 0x63, 0x12, 0x58,
0xd6, 0x9c, 0xf7, 0xa2, 0xde, 0xf9, 0xde, 0x14,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10};
static void modL(u8 *r, i64 x[64])
{
for (unsigned i = 63; i >= 32; i--) {
i64 carry = 0;
FOR (j, i-32, i-12) {
x[j] += carry - 16 * x[i] * L[j - (i - 32)];
carry = (x[j] + 128) >> 8;
x[j] -= carry * (1 << 8);
}
x[i-12] += carry;
x[i] = 0;
}
i64 carry = 0;
FOR (i, 0, 32) {
x[i] += carry - (x[31] >> 4) * L[i];
carry = x[i] >> 8;
x[i] &= 255;
}
FOR (i, 0, 32) {
x[i] -= carry * L[i];
}
FOR (i, 0, 32) {
x[i+1] += x[i] >> 8;
r[i ] = x[i] & 255;
}
}
static void reduce(u8 r[64])
{
i64 x[64];
FOR (i, 0, 64) {
x[i] = (u64) r[i];
r[i] = 0;
}
modL(r, x);
WIPE_BUFFER(x);
}
// r = (a * b) + c
static void mul_add(u8 r[32], const u8 a[32], const u8 b[32], const u8 c[32])
{
i64 s[64];
FOR (i, 0, 32) { s[i] = (u64) c[i]; }
FOR (i, 32, 64) { s[i] = 0; }
FOR (i, 0, 32) {
FOR (j, 0, 32) {
s[i+j] += a[i] * (u64) b[j];
}
}
modL(r, s);
WIPE_BUFFER(s);
}
static int is_above_L(const u8 a[32])
{
for (int i = 31; i >= 0; i--) {
if (a[i] > L[i]) { return 1; }
if (a[i] < L[i]) { return 0; }
}
return 1;
}
// Point in a twisted Edwards curve,
// in extended projective coordinates.
// x = X/Z, y = Y/Z, T = XY/Z
typedef struct { fe X; fe Y; fe Z; fe T; } ge;
typedef struct { fe Yp; fe Ym; fe Z; fe T2; } ge_cached;
static void ge_zero(ge *p)
{
fe_0(p->X);
fe_1(p->Y);
fe_1(p->Z);
fe_0(p->T);
}
static void ge_tobytes(u8 s[32], const ge *h)
{
fe recip, x, y;
fe_invert(recip, h->Z);
fe_mul(x, h->X, recip);
fe_mul(y, h->Y, recip);
fe_tobytes(s, y);
s[31] ^= fe_isnegative(x) << 7;
WIPE_BUFFER(recip);
WIPE_BUFFER(x);
WIPE_BUFFER(y);
}
// Variable time! s must not be secret!
static int ge_frombytes_neg_vartime(ge *h, const u8 s[32])
{
static const fe d = {
-10913610, 13857413, -15372611, 6949391, 114729,
-8787816, -6275908, -3247719, -18696448, -12055116
} ;
static const fe sqrtm1 = {
-32595792, -7943725, 9377950, 3500415, 12389472,
-272473, -25146209, -2005654, 326686, 11406482
} ;
fe u, v, v3, vxx, check; // no secret, no wipe
fe_frombytes(h->Y, s);
fe_1(h->Z);
fe_sq(u, h->Y); // y^2
fe_mul(v, u, d);
fe_sub(u, u, h->Z); // u = y^2-1
fe_add(v, v, h->Z); // v = dy^2+1
fe_sq(v3, v);
fe_mul(v3, v3, v); // v3 = v^3
fe_sq(h->X, v3);
fe_mul(h->X, h->X, v);
fe_mul(h->X, h->X, u); // x = uv^7
fe_pow22523(h->X, h->X); // x = (uv^7)^((q-5)/8)
fe_mul(h->X, h->X, v3);
fe_mul(h->X, h->X, u); // x = uv^3(uv^7)^((q-5)/8)
fe_sq(vxx, h->X);
fe_mul(vxx, vxx, v);
fe_sub(check, vxx, u); // vx^2-u
if (fe_isnonzero(check)) {
fe_add(check, vxx, u); // vx^2+u
if (fe_isnonzero(check)) {
return -1;
}
fe_mul(h->X, h->X, sqrtm1);
}
if (fe_isnegative(h->X) == (s[31] >> 7)) {
fe_neg(h->X, h->X);
}
fe_mul(h->T, h->X, h->Y);
return 0;
}
static void ge_cache(ge_cached *c, const ge *p)
{
static const fe D2 = { // - 2 * 121665 / 121666
-21827239, -5839606, -30745221, 13898782, 229458,
15978800, -12551817, -6495438, 29715968, 9444199
};
fe_add (c->Yp, p->Y, p->X);
fe_sub (c->Ym, p->Y, p->X);
fe_copy(c->Z , p->Z );
fe_mul (c->T2, p->T, D2 );
}
static void ge_add(ge *s, const ge *p, const ge_cached *q)
{
fe a, b; // not used to process secrets, no need to wipe
fe_add(a , p->Y, p->X );
fe_sub(b , p->Y, p->X );
fe_mul(a , a , q->Yp);
fe_mul(b , b , q->Ym);
fe_add(s->Y, a , b );
fe_sub(s->X, a , b );
fe_add(s->Z, p->Z, p->Z );
fe_mul(s->Z, s->Z, q->Z );
fe_mul(s->T, p->T, q->T2);
fe_add(a , s->Z, s->T );
fe_sub(b , s->Z, s->T );
fe_mul(s->T, s->X, s->Y);
fe_mul(s->X, s->X, b );
fe_mul(s->Y, s->Y, a );
fe_mul(s->Z, a , b );
}
static void ge_sub(ge *s, const ge *p, const ge_cached *q)
{
ge_cached neg;
fe_copy(neg.Ym, q->Yp);
fe_copy(neg.Yp, q->Ym);
fe_copy(neg.Z , q->Z );
fe_neg (neg.T2, q->T2);
ge_add(s, p, &neg);
}
static void ge_madd(ge *s, const ge *p, const fe yp, const fe ym, const fe t2,
fe a, fe b)
{
fe_add(a , p->Y, p->X );
fe_sub(b , p->Y, p->X );
fe_mul(a , a , yp );
fe_mul(b , b , ym );
fe_add(s->Y, a , b );
fe_sub(s->X, a , b );
fe_add(s->Z, p->Z, p->Z );
fe_mul(s->T, p->T, t2 );
fe_add(a , s->Z, s->T );
fe_sub(b , s->Z, s->T );
fe_mul(s->T, s->X, s->Y);
fe_mul(s->X, s->X, b );
fe_mul(s->Y, s->Y, a );
fe_mul(s->Z, a , b );
}
static void ge_double(ge *s, const ge *p, ge *q)
{
fe_sq (q->X, p->X);
fe_sq (q->Y, p->Y);
fe_sq2(q->Z, p->Z);
fe_add(q->T, p->X, p->Y);
fe_sq (s->T, q->T);
fe_add(q->T, q->Y, q->X);
fe_sub(q->Y, q->Y, q->X);
fe_sub(q->X, s->T, q->T);
fe_sub(q->Z, q->Z, q->Y);
fe_mul(s->X, q->X , q->Z);
fe_mul(s->Y, q->T , q->Y);
fe_mul(s->Z, q->Y , q->Z);
fe_mul(s->T, q->X , q->T);
}
// Compute signed sliding windows (either 0, or odd numbers between -15 and 15)
static void slide(i8 adds[258], const u8 scalar[32])
{
FOR (i, 0, 256) { adds[i] = scalar_bit(scalar, i); }
FOR (i, 256, 258) { adds[i] = 0; }
FOR (i, 0, 254) {
if (adds[i] != 0) {
// base value of the 5-bit window
FOR (j, 1, 5) {
adds[i ] |= adds[i+j] << j;
adds[i+j] = 0;
}
if (adds[i] > 16) {
// go back to [-15, 15], propagate carry.
adds[i] -= 32;
int j = i + 5;
while (adds[j] != 0) {
adds[j] = 0;
j++;
}
adds[j] = 1;
}
}
}
}
// Look up table for sliding windows
static void ge_precompute(ge_cached lut[8], const ge *P1)
{
ge P2, tmp;
ge_double(&P2, P1, &tmp);
ge_cache(&lut[0], P1);
FOR (i, 0, 7) {
ge_add(&tmp, &P2, &lut[i]);
ge_cache(&lut[i+1], &tmp);
}
}
// Could be a function, but the macro avoids some overhead.
#define LUT_ADD(sum, lut, adds, i) \
if (adds[i] > 0) { ge_add(sum, sum, &lut[ adds[i] / 2]); } \
if (adds[i] < 0) { ge_sub(sum, sum, &lut[-adds[i] / 2]); }
// Variable time! P, sP, and sB must not be secret!
static void ge_double_scalarmult_vartime(ge *sum, const ge *P,
u8 p[32], u8 b[32])
{
static const fe X = { -14297830, -7645148, 16144683, -16471763, 27570974,
-2696100, -26142465, 8378389, 20764389, 8758491 };
static const fe Y = { -26843541, -6710886, 13421773, -13421773, 26843546,
6710886, -13421773, 13421773, -26843546, -6710886 };
ge B;
fe_copy(B.X, X);
fe_copy(B.Y, Y);
fe_1 (B.Z);
fe_mul (B.T, X, Y);
// cached points for addition
ge_cached cP[8]; ge_precompute(cP, P);
ge_cached cB[8]; ge_precompute(cB, &B);
i8 p_adds[258]; slide(p_adds, p);
i8 b_adds[258]; slide(b_adds, b);
// Avoid the first doublings
int i = 253;
while (i >= 0 &&
p_adds[i] == 0 &&
b_adds[i] == 0) {
i--;
}
// Merged double and add ladder
ge_zero(sum);
LUT_ADD(sum, cP, p_adds, i);
LUT_ADD(sum, cB, b_adds, i);
i--;
while (i >= 0) {
ge_double(sum, sum, &B); // B is no longer used, we can overwrite it
LUT_ADD(sum, cP, p_adds, i);
LUT_ADD(sum, cB, b_adds, i);
i--;
}
}
// 5-bit signed comb in cached format (Niels coordinates, Z=1)
static const fe comb_Yp[16] = {
{2615675, 9989699, 17617367, -13953520, -8802803,
1447286, -8909978, -270892, -12199203, -11617247},
{-1271192, 4785266, -29856067, -6036322, -10435381,
15493337, 20321440, -6036064, 15902131, 13420909},
{-26170888, -12891603, 9568996, -6197816, 26424622,
16308973, -4518568, -3771275, -15522557, 3991142},
{-25875044, 1958396, 19442242, -9809943, -26099408,
-18589, -30794750, -14100910, 4971028, -10535388},
{-13896937, -7357727, -12131124, 617289, -33188817,
10080542, 6402555, 10779157, 1176712, 2472642},
{71503, 12662254, -17008072, -8370006, 23408384,
-12897959, 32287612, 11241906, -16724175, 15336924},
{27397666, 4059848, 23573959, 8868915, -10602416,
-10456346, -22812831, -9666299, 31810345, -2695469},
{-3418193, -694531, 2320482, -11850408, -1981947,
-9606132, 23743894, 3933038, -25004889, -4478918},
{-4448372, 5537982, -4805580, 14016777, 15544316,
16039459, -7143453, -8003716, -21904564, 8443777},
{32495180, 15749868, 2195406, -15542321, -3213890,
-4030779, -2915317, 12751449, -1872493, 11926798},
{26779741, 12553580, -24344000, -4071926, -19447556,
-13464636, 21989468, 7826656, -17344881, 10055954},
{5848288, -1639207, -10452929, -11760637, 6484174,
-5895268, -11561603, 587105, -19220796, 14378222},
{32050187, 12536702, 9206308, -10016828, -13333241,
-4276403, -24225594, 14562479, -31803624, -9967812},
{23536033, -6219361, 199701, 4574817, 30045793,
7163081, -2244033, 883497, 10960746, -14779481},
{-8143354, -11558749, 15772067, 14293390, 5914956,
-16702904, -7410985, 7536196, 6155087, 16571424},
{6211591, -11166015, 24568352, 2768318, -10822221,
11922793, 33211827, 3852290, -13160369, -8855385},
};
static const fe comb_Ym[16] = {
{8873912, 14981221, 13714139, 6923085, 25481101,
4243739, 4646647, -203847, 9015725, -16205935},
{-1827892, 15407265, 2351140, -11810728, 28403158,
-1487103, -15057287, -4656433, -3780118, -1145998},
{-30623162, -11845055, -11327147, -16008347, 17564978,
-1449578, -20580262, 14113978, 29643661, 15580734},
{-15109423, 13348938, -14756006, 14132355, 30481360,
1830723, -240510, 9371801, -13907882, 8024264},
{25119567, 5628696, 10185251, -9279452, 683770,
-14523112, -7982879, -16450545, 1431333, -13253541},
{-8390493, 1276691, 19008763, -12736675, -9249429,
-12526388, 17434195, -13761261, 18962694, -1227728},
{26361856, -12366343, 8941415, 15163068, 7069802,
-7240693, -18656349, 8167008, 31106064, -1670658},
{-5677136, -11012483, -1246680, -6422709, 14772010,
1829629, -11724154, -15914279, -18177362, 1301444},
{937094, 12383516, -22597284, 7580462, -18767748,
13813292, -2323566, 13503298, 11510849, -10561992},
{28028043, 14715827, -6558532, -1773240, 27563607,
-9374554, 3201863, 8865591, -16953001, 7659464},
{13628467, 5701368, 4674031, 11935670, 11461401,
10699118, 31846435, -114971, -8269924, -14777505},
{-22124018, -12859127, 11966893, 1617732, 30972446,
-14350095, -21822286, 8369862, -29443219, -15378798},
{290131, -471434, 8840522, -2654851, 25963762,
-11578288, -7227978, 13847103, 30641797, 6003514},
{-23547482, -11475166, -11913550, 9374455, 22813401,
-5707910, 26635288, 9199956, 20574690, 2061147},
{9715324, 7036821, -17981446, -11505533, 26555178,
-3571571, 5697062, -14128022, 2795223, 9694380},
{14864569, -6319076, -3080, -8151104, 4994948,
-1572144, -41927, 9269803, 13881712, -13439497},
};
static const fe comb_T2[16] = {
{-18494317, 2686822, 18449263, -13905325, 5966562,
-3368714, 2738304, -8583315, 15987143, 12180258},
{-33336513, -13705917, -18473364, -5039204, -4268481,
-4136039, -8192211, -2935105, -19354402, 5995895},
{-19753139, -1729018, 21880604, 13471713, 28315373,
-8530159, -17492688, 11730577, -8790216, 3942124},
{17278020, 3905045, 29577748, 11151940, 18451761,
-6801382, 31480073, -13819665, 26308905, 10868496},
{26937294, 3313561, 28601532, -3497112, -22814130,
11073654, 8956359, -16757370, 13465868, 16623983},
{-5468054, 6059101, -31275300, 2469124, 26532937,
8152142, 6423741, -11427054, -15537747, -10938247},
{-11303505, -9659620, -12354748, -9331434, 19501116,
-9146390, -841918, -5315657, 8903828, 8839982},
{16603354, -215859, 1591180, 3775832, -705596,
-13913449, 26574704, 14963118, 19649719, 6562441},
{33188866, -12232360, -24929148, -6133828, 21818432,
11040754, -3041582, -3524558, -29364727, -10264096},
{-20704194, -12560423, -1235774, -785473, 13240395,
4831780, -472624, -3796899, 25480903, -15422283},
{-2204347, -16313180, -21388048, 7520851, -8697745,
-14460961, 20894017, 12210317, -475249, -2319102},
{-16407882, 4940236, -21194947, 10781753, 22248400,
14425368, 14866511, -7552907, 12148703, -7885797},
{16376744, 15908865, -30663553, 4663134, -30882819,
-10105163, 19294784, -10800440, -33259252, 2563437},
{30208741, 11594088, -15145888, 15073872, 5279309,
-9651774, 8273234, 4796404, -31270809, -13316433},
{-17802574, 14455251, 27149077, -7832700, -29163160,
-7246767, 17498491, -4216079, 31788733, -14027536},
{-25233439, -9389070, -6618212, -3268087, -521386,
-7350198, 21035059, -14970947, 25910190, 11122681},
};
static void ge_scalarmult_base(ge *p, const u8 scalar[32])
{
// 5-bits signed comb, from Mike Hamburg's
// Fast and compact elliptic-curve cryptography (2012)
static const u8 half_mod_L[32] = { // 1 / 2 modulo L
0xf7, 0xe9, 0x7a, 0x2e, 0x8d, 0x31, 0x09, 0x2c,
0x6b, 0xce, 0x7b, 0x51, 0xef, 0x7c, 0x6f, 0x0a,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08,
};
static const u8 half_ones[32] = { // (2^255 - 1) / 2 modulo L
0x42, 0x9a, 0xa3, 0xba, 0x23, 0xa5, 0xbf, 0xcb,
0x11, 0x5b, 0x9d, 0xc5, 0x74, 0x95, 0xf3, 0xb6,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x07,
};
// All bits set form: 1 means 1, 0 means -1
u8 s_scalar[32];
mul_add(s_scalar, scalar, half_mod_L, half_ones);
// Double and add ladder
fe yp, ym, t2, n2, a, b; // temporaries for addition
ge dbl; // temporary for doublings
ge_zero(p);
for (int i = 50; i >= 0; i--) {
if (i < 50) {
ge_double(p, p, &dbl);
}
fe_1(yp);
fe_1(ym);
fe_0(t2);
u8 teeth = scalar_bit(s_scalar, i)
+ (scalar_bit(s_scalar, i + 51) << 1)
+ (scalar_bit(s_scalar, i + 102) << 2)
+ (scalar_bit(s_scalar, i + 153) << 3)
+ (scalar_bit(s_scalar, i + 204) << 4);
u8 high = teeth >> 4;
u8 index = (teeth ^ (high - 1)) & 15;
FOR (j, 0, 16) {
i32 select = 1 & (((j ^ index) - 1) >> 8);
fe_ccopy(yp, comb_Yp[j], select);
fe_ccopy(ym, comb_Ym[j], select);
fe_ccopy(t2, comb_T2[j], select);
}
fe_neg(n2, t2);
fe_cswap(t2, n2, high);
fe_cswap(yp, ym, high);
ge_madd(p, p, ym, yp, n2, a, b);
}
WIPE_CTX(&dbl);
WIPE_BUFFER(a); WIPE_BUFFER(yp); WIPE_BUFFER(t2);
WIPE_BUFFER(b); WIPE_BUFFER(ym); WIPE_BUFFER(n2);
WIPE_BUFFER(s_scalar);
}
void crypto_sign_public_key(u8 public_key[32],
const u8 secret_key[32])
{
u8 a[64];
HASH(a, secret_key, 32);
trim_scalar(a);
ge A;
ge_scalarmult_base(&A, a);
ge_tobytes(public_key, &A);
WIPE_BUFFER(a);
WIPE_CTX(&A);
}
void crypto_sign_init_first_pass(crypto_sign_ctx *ctx,
const u8 secret_key[32],
const u8 public_key[32])
{
u8 *a = ctx->buf;
u8 *prefix = ctx->buf + 32;
HASH(a, secret_key, 32);
trim_scalar(a);
if (public_key == 0) {
crypto_sign_public_key(ctx->pk, secret_key);
} else {
FOR (i, 0, 32) {
ctx->pk[i] = public_key[i];
}
}
// Constructs the "random" nonce from the secret key and message.
// An actual random number would work just fine, and would save us
// the trouble of hashing the message twice. If we did that
// however, the user could fuck it up and reuse the nonce.
HASH_INIT (&ctx->hash);
HASH_UPDATE(&ctx->hash, prefix , 32);
}
void crypto_sign_update(crypto_sign_ctx *ctx, const u8 *msg, size_t msg_size)
{
HASH_UPDATE(&ctx->hash, msg, msg_size);
}
void crypto_sign_init_second_pass(crypto_sign_ctx *ctx)
{
u8 *r = ctx->buf + 32;
u8 *half_sig = ctx->buf + 64;
HASH_FINAL(&ctx->hash, r);
reduce(r);
// first half of the signature = "random" nonce times basepoint
ge R;
ge_scalarmult_base(&R, r);
ge_tobytes(half_sig, &R);
WIPE_CTX(&R);
// Hash R, the public key, and the message together.
// It cannot be done in parallel with the first hash.
HASH_INIT (&ctx->hash);
HASH_UPDATE(&ctx->hash, half_sig, 32);
HASH_UPDATE(&ctx->hash, ctx->pk , 32);
}
void crypto_sign_final(crypto_sign_ctx *ctx, u8 signature[64])
{
u8 *a = ctx->buf;
u8 *r = ctx->buf + 32;
u8 *half_sig = ctx->buf + 64;
u8 h_ram[64];
HASH_FINAL(&ctx->hash, h_ram);
reduce(h_ram); // reduce the hash modulo L
FOR (i, 0, 32) {
signature[i] = half_sig[i];
}
mul_add(signature + 32, h_ram, a, r); // s = h_ram * a + r
WIPE_CTX(ctx);
WIPE_BUFFER(h_ram);
}
void crypto_sign(u8 signature[64],
const u8 secret_key[32],
const u8 public_key[32],
const u8 *message, size_t message_size)
{
crypto_sign_ctx ctx;
crypto_sign_init_first_pass (&ctx, secret_key, public_key);
crypto_sign_update (&ctx, message, message_size);
crypto_sign_init_second_pass(&ctx);
crypto_sign_update (&ctx, message, message_size);
crypto_sign_final (&ctx, signature);
}
void crypto_check_init(crypto_check_ctx *ctx,
const u8 signature[64],
const u8 public_key[32])
{
FOR (i, 0, 64) { ctx->sig[i] = signature [i]; }
FOR (i, 0, 32) { ctx->pk [i] = public_key[i]; }
HASH_INIT (&ctx->hash);
HASH_UPDATE(&ctx->hash, signature , 32);
HASH_UPDATE(&ctx->hash, public_key, 32);
}
void crypto_check_update(crypto_check_ctx *ctx, const u8 *msg, size_t msg_size)
{
HASH_UPDATE(&ctx->hash, msg , msg_size);
}
int crypto_check_final(crypto_check_ctx *ctx)
{
ge diff, A;
u8 h_ram[64], R_check[32];
u8 *s = ctx->sig + 32; // s
u8 *R = ctx->sig; // R
if (ge_frombytes_neg_vartime(&A, ctx->pk) ||
is_above_L(s)) { // prevent s malleability
return -1;
}
HASH_FINAL(&ctx->hash, h_ram);
reduce(h_ram);
ge_double_scalarmult_vartime(&diff, &A, h_ram, s);
ge_tobytes(R_check, &diff); // R_check = s*B - h_ram*A
return crypto_verify32(R, R_check); // R == R_check ? OK : fail
// No secret, no wipe
}
int crypto_check(const u8 signature[64],
const u8 public_key[32],
const u8 *message, size_t message_size)
{
crypto_check_ctx ctx;
crypto_check_init(&ctx, signature, public_key);
crypto_check_update(&ctx, message, message_size);
return crypto_check_final(&ctx);
}
////////////////////
/// Key exchange ///
////////////////////
int crypto_key_exchange(u8 shared_key[32],
const u8 your_secret_key [32],
const u8 their_public_key[32])
{
u8 raw_shared_secret[32];
int status = crypto_x25519(raw_shared_secret,
your_secret_key, their_public_key);
crypto_chacha20_H(shared_key, raw_shared_secret, zero);
WIPE_BUFFER(raw_shared_secret);
return status;
}
////////////////////////////////
/// Authenticated encryption ///
////////////////////////////////
static void lock_ad_padding(crypto_lock_ctx *ctx)
{
if (ctx->ad_phase) {
ctx->ad_phase = 0;
crypto_poly1305_update(&ctx->poly, zero, ALIGN(ctx->ad_size, 16));
}
}
void crypto_lock_init(crypto_lock_ctx *ctx,
const u8 key[32], const u8 nonce[24])
{
u8 auth_key[64]; // "Wasting" the whole Chacha block is faster
ctx->ad_phase = 1;
ctx->ad_size = 0;
ctx->message_size = 0;
crypto_chacha20_x_init(&ctx->chacha, key, nonce);
crypto_chacha20_stream(&ctx->chacha, auth_key, 64);
crypto_poly1305_init (&ctx->poly , auth_key);
WIPE_BUFFER(auth_key);
}
void crypto_lock_auth_ad(crypto_lock_ctx *ctx, const u8 *msg, size_t msg_size)
{
crypto_poly1305_update(&ctx->poly, msg, msg_size);
ctx->ad_size += msg_size;
}
void crypto_lock_auth_message(crypto_lock_ctx *ctx,
const u8 *cipher_text, size_t text_size)
{
lock_ad_padding(ctx);
ctx->message_size += text_size;
crypto_poly1305_update(&ctx->poly, cipher_text, text_size);
}
void crypto_lock_update(crypto_lock_ctx *ctx, u8 *cipher_text,
const u8 *plain_text, size_t text_size)
{
crypto_chacha20_encrypt(&ctx->chacha, cipher_text, plain_text, text_size);
crypto_lock_auth_message(ctx, cipher_text, text_size);
}
void crypto_lock_final(crypto_lock_ctx *ctx, u8 mac[16])
{
lock_ad_padding(ctx);
u8 sizes[16]; // Not secret, not wiped
store64_le(sizes + 0, ctx->ad_size);
store64_le(sizes + 8, ctx->message_size);
crypto_poly1305_update(&ctx->poly, zero, ALIGN(ctx->message_size, 16));
crypto_poly1305_update(&ctx->poly, sizes, 16);
crypto_poly1305_final (&ctx->poly, mac);
WIPE_CTX(ctx);
}
void crypto_unlock_update(crypto_lock_ctx *ctx, u8 *plain_text,
const u8 *cipher_text, size_t text_size)
{
crypto_unlock_auth_message(ctx, cipher_text, text_size);
crypto_chacha20_encrypt(&ctx->chacha, plain_text, cipher_text, text_size);
}
int crypto_unlock_final(crypto_lock_ctx *ctx, const u8 mac[16])
{
u8 real_mac[16];
crypto_lock_final(ctx, real_mac);
int mismatch = crypto_verify16(real_mac, mac);
WIPE_BUFFER(real_mac);
return mismatch;
}
void crypto_lock_aead(u8 mac[16],
u8 *cipher_text,
const u8 key[32],
const u8 nonce[24],
const u8 *ad , size_t ad_size,
const u8 *plain_text, size_t text_size)
{
crypto_lock_ctx ctx;
crypto_lock_init (&ctx, key, nonce);
crypto_lock_auth_ad(&ctx, ad, ad_size);
crypto_lock_update (&ctx, cipher_text, plain_text, text_size);
crypto_lock_final (&ctx, mac);
}
int crypto_unlock_aead(u8 *plain_text,
const u8 key[32],
const u8 nonce[24],
const u8 mac[16],
const u8 *ad , size_t ad_size,
const u8 *cipher_text, size_t text_size)
{
crypto_unlock_ctx ctx;
crypto_unlock_init (&ctx, key, nonce);
crypto_unlock_auth_ad (&ctx, ad, ad_size);
crypto_unlock_auth_message(&ctx, cipher_text, text_size);
crypto_chacha_ctx chacha_ctx = ctx.chacha; // avoid the wiping...
if (crypto_unlock_final(&ctx, mac)) { // ...that occurs here
WIPE_CTX(&chacha_ctx);
return -1; // reject forgeries before wasting our time decrypting
}
crypto_chacha20_encrypt(&chacha_ctx, plain_text, cipher_text, text_size);
WIPE_CTX(&chacha_ctx);
return 0;
}
void crypto_lock(u8 mac[16],
u8 *cipher_text,
const u8 key[32],
const u8 nonce[24],
const u8 *plain_text, size_t text_size)
{
crypto_lock_aead(mac, cipher_text, key, nonce, 0, 0, plain_text, text_size);
}
int crypto_unlock(u8 *plain_text,
const u8 key[32],
const u8 nonce[24],
const u8 mac[16],
const u8 *cipher_text, size_t text_size)
{
return crypto_unlock_aead(plain_text, key, nonce, mac, 0, 0,
cipher_text, text_size);
}
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