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/*
chacha-merged.c version 20080118
D. J. Bernstein
Public domain.
*/
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "core.h"
#include "crypto_stream_chacha20.h"
#include "private/common.h"
#include "utils.h"
#include "../stream_chacha20.h"
#include "chacha20_ref.h"
struct chacha_ctx {
uint32_t input[16];
};
typedef struct chacha_ctx chacha_ctx;
#define U32C(v) (v##U)
#define U32V(v) ((uint32_t)(v) &U32C(0xFFFFFFFF))
#define ROTATE(v, c) (ROTL32(v, c))
#define XOR(v, w) ((v) ^ (w))
#define PLUS(v, w) (U32V((v) + (w)))
#define PLUSONE(v) (PLUS((v), 1))
#define QUARTERROUND(a, b, c, d) \
a = PLUS(a, b); \
d = ROTATE(XOR(d, a), 16); \
c = PLUS(c, d); \
b = ROTATE(XOR(b, c), 12); \
a = PLUS(a, b); \
d = ROTATE(XOR(d, a), 8); \
c = PLUS(c, d); \
b = ROTATE(XOR(b, c), 7);
static void
chacha_keysetup(chacha_ctx *ctx, const uint8_t *k)
{
ctx->input[0] = U32C(0x61707865);
ctx->input[1] = U32C(0x3320646e);
ctx->input[2] = U32C(0x79622d32);
ctx->input[3] = U32C(0x6b206574);
ctx->input[4] = LOAD32_LE(k + 0);
ctx->input[5] = LOAD32_LE(k + 4);
ctx->input[6] = LOAD32_LE(k + 8);
ctx->input[7] = LOAD32_LE(k + 12);
ctx->input[8] = LOAD32_LE(k + 16);
ctx->input[9] = LOAD32_LE(k + 20);
ctx->input[10] = LOAD32_LE(k + 24);
ctx->input[11] = LOAD32_LE(k + 28);
}
static void
chacha_ivsetup(chacha_ctx *ctx, const uint8_t *iv, const uint8_t *counter)
{
ctx->input[12] = counter == NULL ? 0 : LOAD32_LE(counter + 0);
ctx->input[13] = counter == NULL ? 0 : LOAD32_LE(counter + 4);
ctx->input[14] = LOAD32_LE(iv + 0);
ctx->input[15] = LOAD32_LE(iv + 4);
}
static void
chacha_ietf_ivsetup(chacha_ctx *ctx, const uint8_t *iv, const uint8_t *counter)
{
ctx->input[12] = counter == NULL ? 0 : LOAD32_LE(counter);
ctx->input[13] = LOAD32_LE(iv + 0);
ctx->input[14] = LOAD32_LE(iv + 4);
ctx->input[15] = LOAD32_LE(iv + 8);
}
static void
chacha20_encrypt_bytes(chacha_ctx *ctx, const uint8_t *m, uint8_t *c,
unsigned long long bytes)
{
uint32_t x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14,
x15;
uint32_t j0, j1, j2, j3, j4, j5, j6, j7, j8, j9, j10, j11, j12, j13, j14,
j15;
uint8_t *ctarget = NULL;
uint8_t tmp[64];
unsigned int i;
if (!bytes) {
return; /* LCOV_EXCL_LINE */
}
j0 = ctx->input[0];
j1 = ctx->input[1];
j2 = ctx->input[2];
j3 = ctx->input[3];
j4 = ctx->input[4];
j5 = ctx->input[5];
j6 = ctx->input[6];
j7 = ctx->input[7];
j8 = ctx->input[8];
j9 = ctx->input[9];
j10 = ctx->input[10];
j11 = ctx->input[11];
j12 = ctx->input[12];
j13 = ctx->input[13];
j14 = ctx->input[14];
j15 = ctx->input[15];
for (;;) {
if (bytes < 64) {
memset(tmp, 0, 64);
for (i = 0; i < bytes; ++i) {
tmp[i] = m[i];
}
m = tmp;
ctarget = c;
c = tmp;
}
x0 = j0;
x1 = j1;
x2 = j2;
x3 = j3;
x4 = j4;
x5 = j5;
x6 = j6;
x7 = j7;
x8 = j8;
x9 = j9;
x10 = j10;
x11 = j11;
x12 = j12;
x13 = j13;
x14 = j14;
x15 = j15;
for (i = 20; i > 0; i -= 2) {
QUARTERROUND(x0, x4, x8, x12)
QUARTERROUND(x1, x5, x9, x13)
QUARTERROUND(x2, x6, x10, x14)
QUARTERROUND(x3, x7, x11, x15)
QUARTERROUND(x0, x5, x10, x15)
QUARTERROUND(x1, x6, x11, x12)
QUARTERROUND(x2, x7, x8, x13)
QUARTERROUND(x3, x4, x9, x14)
}
x0 = PLUS(x0, j0);
x1 = PLUS(x1, j1);
x2 = PLUS(x2, j2);
x3 = PLUS(x3, j3);
x4 = PLUS(x4, j4);
x5 = PLUS(x5, j5);
x6 = PLUS(x6, j6);
x7 = PLUS(x7, j7);
x8 = PLUS(x8, j8);
x9 = PLUS(x9, j9);
x10 = PLUS(x10, j10);
x11 = PLUS(x11, j11);
x12 = PLUS(x12, j12);
x13 = PLUS(x13, j13);
x14 = PLUS(x14, j14);
x15 = PLUS(x15, j15);
x0 = XOR(x0, LOAD32_LE(m + 0));
x1 = XOR(x1, LOAD32_LE(m + 4));
x2 = XOR(x2, LOAD32_LE(m + 8));
x3 = XOR(x3, LOAD32_LE(m + 12));
x4 = XOR(x4, LOAD32_LE(m + 16));
x5 = XOR(x5, LOAD32_LE(m + 20));
x6 = XOR(x6, LOAD32_LE(m + 24));
x7 = XOR(x7, LOAD32_LE(m + 28));
x8 = XOR(x8, LOAD32_LE(m + 32));
x9 = XOR(x9, LOAD32_LE(m + 36));
x10 = XOR(x10, LOAD32_LE(m + 40));
x11 = XOR(x11, LOAD32_LE(m + 44));
x12 = XOR(x12, LOAD32_LE(m + 48));
x13 = XOR(x13, LOAD32_LE(m + 52));
x14 = XOR(x14, LOAD32_LE(m + 56));
x15 = XOR(x15, LOAD32_LE(m + 60));
j12 = PLUSONE(j12);
/* LCOV_EXCL_START */
if (!j12) {
j13 = PLUSONE(j13);
}
/* LCOV_EXCL_STOP */
STORE32_LE(c + 0, x0);
STORE32_LE(c + 4, x1);
STORE32_LE(c + 8, x2);
STORE32_LE(c + 12, x3);
STORE32_LE(c + 16, x4);
STORE32_LE(c + 20, x5);
STORE32_LE(c + 24, x6);
STORE32_LE(c + 28, x7);
STORE32_LE(c + 32, x8);
STORE32_LE(c + 36, x9);
STORE32_LE(c + 40, x10);
STORE32_LE(c + 44, x11);
STORE32_LE(c + 48, x12);
STORE32_LE(c + 52, x13);
STORE32_LE(c + 56, x14);
STORE32_LE(c + 60, x15);
if (bytes <= 64) {
if (bytes < 64) {
for (i = 0; i < (unsigned int) bytes; ++i) {
ctarget[i] = c[i]; /* ctarget cannot be NULL */
}
}
ctx->input[12] = j12;
ctx->input[13] = j13;
return;
}
bytes -= 64;
c += 64;
m += 64;
}
}
static int
stream_ref(unsigned char *c, unsigned long long clen, const unsigned char *n,
const unsigned char *k)
{
struct chacha_ctx ctx;
if (!clen) {
return 0;
}
COMPILER_ASSERT(crypto_stream_chacha20_KEYBYTES == 256 / 8);
chacha_keysetup(&ctx, k);
chacha_ivsetup(&ctx, n, NULL);
memset(c, 0, clen);
chacha20_encrypt_bytes(&ctx, c, c, clen);
sodium_memzero(&ctx, sizeof ctx);
return 0;
}
static int
stream_ietf_ext_ref(unsigned char *c, unsigned long long clen,
const unsigned char *n, const unsigned char *k)
{
struct chacha_ctx ctx;
if (!clen) {
return 0;
}
COMPILER_ASSERT(crypto_stream_chacha20_KEYBYTES == 256 / 8);
chacha_keysetup(&ctx, k);
chacha_ietf_ivsetup(&ctx, n, NULL);
memset(c, 0, clen);
chacha20_encrypt_bytes(&ctx, c, c, clen);
sodium_memzero(&ctx, sizeof ctx);
return 0;
}
static int
stream_ref_xor_ic(unsigned char *c, const unsigned char *m,
unsigned long long mlen, const unsigned char *n, uint64_t ic,
const unsigned char *k)
{
struct chacha_ctx ctx;
uint8_t ic_bytes[8];
uint32_t ic_high;
uint32_t ic_low;
if (!mlen) {
return 0;
}
ic_high = U32V(ic >> 32);
ic_low = U32V(ic);
STORE32_LE(&ic_bytes[0], ic_low);
STORE32_LE(&ic_bytes[4], ic_high);
chacha_keysetup(&ctx, k);
chacha_ivsetup(&ctx, n, ic_bytes);
chacha20_encrypt_bytes(&ctx, m, c, mlen);
sodium_memzero(&ctx, sizeof ctx);
return 0;
}
static int
stream_ietf_ext_ref_xor_ic(unsigned char *c, const unsigned char *m,
unsigned long long mlen, const unsigned char *n,
uint32_t ic, const unsigned char *k)
{
struct chacha_ctx ctx;
uint8_t ic_bytes[4];
if (!mlen) {
return 0;
}
STORE32_LE(ic_bytes, ic);
chacha_keysetup(&ctx, k);
chacha_ietf_ivsetup(&ctx, n, ic_bytes);
chacha20_encrypt_bytes(&ctx, m, c, mlen);
sodium_memzero(&ctx, sizeof ctx);
return 0;
}
struct crypto_stream_chacha20_implementation
crypto_stream_chacha20_ref_implementation = {
SODIUM_C99(.stream =) stream_ref,
SODIUM_C99(.stream_ietf_ext =) stream_ietf_ext_ref,
SODIUM_C99(.stream_xor_ic =) stream_ref_xor_ic,
SODIUM_C99(.stream_ietf_ext_xor_ic =) stream_ietf_ext_ref_xor_ic
};
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