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337/****************************************************************************
* crypto/chacha_private.h
*
* SPDX-License-Identifier: LicenseRef-NuttX-PublicDomain
*
* D. J. Bernstein
* Public domain.
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <string.h>
#include <sys/types.h>
typedef struct
{
uint32_t input[16]; /* could be compressed */
}
chacha_ctx;
#define U8C(v) (v##U)
#define U32C(v) (v##U)
#define U8V(v) ((uint8_t)(v) & U8C(0xFF))
#define U32V(v) ((uint32_t)(v) & U32C(0xFFFFFFFF))
#define ROTL32(v, n) \
(U32V((v) << (n)) | ((v) >> (32 - (n))))
#define U8TO32_LITTLE(p) \
(((uint32_t)((p)[0])) | \
((uint32_t)((p)[1]) << 8) | \
((uint32_t)((p)[2]) << 16) | \
((uint32_t)((p)[3]) << 24)) \
#define U32TO8_LITTLE(p, v) \
do { \
(p)[0] = U8V((v)); \
(p)[1] = U8V((v) >> 8); \
(p)[2] = U8V((v) >> 16); \
(p)[3] = U8V((v) >> 24); \
} while (0)
#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) \
do \
{ \
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); \
} \
while (0)
static const char sigma[16] = "expand 32-byte k";
static const char tau[16] = "expand 16-byte k";
static inline void hchacha20(FAR uint32_t *derived_key,
FAR const uint8_t *nonce,
FAR const uint8_t *key)
{
int i;
uint32_t x[] =
{
U8TO32_LITTLE(sigma + 0),
U8TO32_LITTLE(sigma + 4),
U8TO32_LITTLE(sigma + 8),
U8TO32_LITTLE(sigma + 12),
U8TO32_LITTLE(key + 0),
U8TO32_LITTLE(key + 4),
U8TO32_LITTLE(key + 8),
U8TO32_LITTLE(key + 12),
U8TO32_LITTLE(key + 16),
U8TO32_LITTLE(key + 20),
U8TO32_LITTLE(key + 24),
U8TO32_LITTLE(key + 28),
U8TO32_LITTLE(nonce + 0),
U8TO32_LITTLE(nonce + 4),
U8TO32_LITTLE(nonce + 8),
U8TO32_LITTLE(nonce + 12)
};
for (i = 20; i > 0; i -= 2)
{
QUARTERROUND(x[0], x[4], x[8], x[12]);
QUARTERROUND(x[1], x[5], x[9], x[13]);
QUARTERROUND(x[2], x[6], x[10], x[14]);
QUARTERROUND(x[3], x[7], x[11], x[15]);
QUARTERROUND(x[0], x[5], x[10], x[15]);
QUARTERROUND(x[1], x[6], x[11], x[12]);
QUARTERROUND(x[2], x[7], x[8], x[13]);
QUARTERROUND(x[3], x[4], x[9], x[14]);
}
memcpy(derived_key + 0, x + 0, sizeof(uint32_t) * 4);
memcpy(derived_key + 4, x + 12, sizeof(uint32_t) * 4);
}
static void chacha_keysetup(FAR chacha_ctx *x,
FAR const uint8_t *k,
FAR uint32_t kbits)
{
FAR const char *constants;
x->input[4] = U8TO32_LITTLE(k + 0);
x->input[5] = U8TO32_LITTLE(k + 4);
x->input[6] = U8TO32_LITTLE(k + 8);
x->input[7] = U8TO32_LITTLE(k + 12);
if (kbits == 256)
{
/* recommended */
k += 16;
constants = sigma;
}
else
{
/* kbits == 128 */
constants = tau;
}
x->input[8] = U8TO32_LITTLE(k + 0);
x->input[9] = U8TO32_LITTLE(k + 4);
x->input[10] = U8TO32_LITTLE(k + 8);
x->input[11] = U8TO32_LITTLE(k + 12);
x->input[0] = U8TO32_LITTLE(constants + 0);
x->input[1] = U8TO32_LITTLE(constants + 4);
x->input[2] = U8TO32_LITTLE(constants + 8);
x->input[3] = U8TO32_LITTLE(constants + 12);
}
static void chacha_ivsetup(FAR chacha_ctx *x,
FAR const uint8_t *iv,
FAR const uint8_t *counter)
{
x->input[12] = counter == NULL ? 0 : U8TO32_LITTLE(counter + 0);
x->input[13] = counter == NULL ? 0 : U8TO32_LITTLE(counter + 4);
x->input[14] = U8TO32_LITTLE(iv + 0);
x->input[15] = U8TO32_LITTLE(iv + 4);
}
static void chacha_encrypt_bytes(FAR chacha_ctx *x,
FAR const uint8_t *m,
FAR uint8_t *c,
uint32_t bytes)
{
uint32_t x0;
uint32_t x1;
uint32_t x2;
uint32_t x3;
uint32_t x4;
uint32_t x5;
uint32_t x6;
uint32_t x7;
uint32_t x8;
uint32_t x9;
uint32_t x10;
uint32_t x11;
uint32_t x12;
uint32_t x13;
uint32_t x14;
uint32_t x15;
uint32_t j0;
uint32_t j1;
uint32_t j2;
uint32_t j3;
uint32_t j4;
uint32_t j5;
uint32_t j6;
uint32_t j7;
uint32_t j8;
uint32_t j9;
uint32_t j10;
uint32_t j11;
uint32_t j12;
uint32_t j13;
uint32_t j14;
uint32_t j15;
FAR uint8_t *ctarget = NULL;
uint8_t tmp[64];
u_int i;
if (!bytes)
{
return;
}
j0 = x->input[0];
j1 = x->input[1];
j2 = x->input[2];
j3 = x->input[3];
j4 = x->input[4];
j5 = x->input[5];
j6 = x->input[6];
j7 = x->input[7];
j8 = x->input[8];
j9 = x->input[9];
j10 = x->input[10];
j11 = x->input[11];
j12 = x->input[12];
j13 = x->input[13];
j14 = x->input[14];
j15 = x->input[15];
for (; ; )
{
if (bytes < 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);
#ifndef KEYSTREAM_ONLY
x0 = XOR(x0, U8TO32_LITTLE(m + 0));
x1 = XOR(x1, U8TO32_LITTLE(m + 4));
x2 = XOR(x2, U8TO32_LITTLE(m + 8));
x3 = XOR(x3, U8TO32_LITTLE(m + 12));
x4 = XOR(x4, U8TO32_LITTLE(m + 16));
x5 = XOR(x5, U8TO32_LITTLE(m + 20));
x6 = XOR(x6, U8TO32_LITTLE(m + 24));
x7 = XOR(x7, U8TO32_LITTLE(m + 28));
x8 = XOR(x8, U8TO32_LITTLE(m + 32));
x9 = XOR(x9, U8TO32_LITTLE(m + 36));
x10 = XOR(x10, U8TO32_LITTLE(m + 40));
x11 = XOR(x11, U8TO32_LITTLE(m + 44));
x12 = XOR(x12, U8TO32_LITTLE(m + 48));
x13 = XOR(x13, U8TO32_LITTLE(m + 52));
x14 = XOR(x14, U8TO32_LITTLE(m + 56));
x15 = XOR(x15, U8TO32_LITTLE(m + 60));
#endif
j12 = PLUSONE(j12);
if (!j12)
{
j13 = PLUSONE(j13);
/* stopping at 2^70 bytes per nonce is user's responsibility */
}
U32TO8_LITTLE(c + 0, x0);
U32TO8_LITTLE(c + 4, x1);
U32TO8_LITTLE(c + 8, x2);
U32TO8_LITTLE(c + 12, x3);
U32TO8_LITTLE(c + 16, x4);
U32TO8_LITTLE(c + 20, x5);
U32TO8_LITTLE(c + 24, x6);
U32TO8_LITTLE(c + 28, x7);
U32TO8_LITTLE(c + 32, x8);
U32TO8_LITTLE(c + 36, x9);
U32TO8_LITTLE(c + 40, x10);
U32TO8_LITTLE(c + 44, x11);
U32TO8_LITTLE(c + 48, x12);
U32TO8_LITTLE(c + 52, x13);
U32TO8_LITTLE(c + 56, x14);
U32TO8_LITTLE(c + 60, x15);
if (bytes <= 64)
{
if (bytes < 64)
{
for (i = 0; i < bytes; ++i)
{
ctarget[i] = c[i];
}
}
x->input[12] = j12;
x->input[13] = j13;
return;
}
bytes -= 64;
c += 64;
#ifndef KEYSTREAM_ONLY
m += 64;
#endif
}
}