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Refactor little-to-big-endian subroutine for magma
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@marcfedorow @beldmit
marcfedorow authored and beldmit committed Jul 2, 2022
1 parent 021a2b6 commit fcca1ab
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107 changes: 107 additions & 0 deletions gost89.c
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Original file line number Diff line number Diff line change
Expand Up @@ -328,6 +328,60 @@ void gostcrypt(gost_ctx * c, const byte * in, byte * out)
out[7] = (byte) (n1 >> 24);
}

/* Low-level encryption routine - encrypts one 64 bit block*/
void magmacrypt(gost_ctx * c, const byte * in, byte * out)
{
register word32 n1, n2; /* As named in the GOST */
n1 = in[7-0] | (in[7-1] << 8) | (in[7-2] << 16) | ((word32) in[7-3] << 24);
n2 = in[7-4] | (in[7-5] << 8) | (in[7-6] << 16) | ((word32) in[7-7] << 24);
/* Instead of swapping halves, swap names each round */

n2 ^= f(c, n1 + c->key[0] + c->mask[0]);
n1 ^= f(c, n2 + c->key[1] + c->mask[1]);
n2 ^= f(c, n1 + c->key[2] + c->mask[2]);
n1 ^= f(c, n2 + c->key[3] + c->mask[3]);
n2 ^= f(c, n1 + c->key[4] + c->mask[4]);
n1 ^= f(c, n2 + c->key[5] + c->mask[5]);
n2 ^= f(c, n1 + c->key[6] + c->mask[6]);
n1 ^= f(c, n2 + c->key[7] + c->mask[7]);

n2 ^= f(c, n1 + c->key[0] + c->mask[0]);
n1 ^= f(c, n2 + c->key[1] + c->mask[1]);
n2 ^= f(c, n1 + c->key[2] + c->mask[2]);
n1 ^= f(c, n2 + c->key[3] + c->mask[3]);
n2 ^= f(c, n1 + c->key[4] + c->mask[4]);
n1 ^= f(c, n2 + c->key[5] + c->mask[5]);
n2 ^= f(c, n1 + c->key[6] + c->mask[6]);
n1 ^= f(c, n2 + c->key[7] + c->mask[7]);

n2 ^= f(c, n1 + c->key[0] + c->mask[0]);
n1 ^= f(c, n2 + c->key[1] + c->mask[1]);
n2 ^= f(c, n1 + c->key[2] + c->mask[2]);
n1 ^= f(c, n2 + c->key[3] + c->mask[3]);
n2 ^= f(c, n1 + c->key[4] + c->mask[4]);
n1 ^= f(c, n2 + c->key[5] + c->mask[5]);
n2 ^= f(c, n1 + c->key[6] + c->mask[6]);
n1 ^= f(c, n2 + c->key[7] + c->mask[7]);

n2 ^= f(c, n1 + c->key[7] + c->mask[7]);
n1 ^= f(c, n2 + c->key[6] + c->mask[6]);
n2 ^= f(c, n1 + c->key[5] + c->mask[5]);
n1 ^= f(c, n2 + c->key[4] + c->mask[4]);
n2 ^= f(c, n1 + c->key[3] + c->mask[3]);
n1 ^= f(c, n2 + c->key[2] + c->mask[2]);
n2 ^= f(c, n1 + c->key[1] + c->mask[1]);
n1 ^= f(c, n2 + c->key[0] + c->mask[0]);

out[7-0] = (byte) (n2 & 0xff);
out[7-1] = (byte) ((n2 >> 8) & 0xff);
out[7-2] = (byte) ((n2 >> 16) & 0xff);
out[7-3] = (byte) (n2 >> 24);
out[7-4] = (byte) (n1 & 0xff);
out[7-5] = (byte) ((n1 >> 8) & 0xff);
out[7-6] = (byte) ((n1 >> 16) & 0xff);
out[7-7] = (byte) (n1 >> 24);
}

/* Low-level decryption routine. Decrypts one 64-bit block */
void gostdecrypt(gost_ctx * c, const byte * in, byte * out)
{
Expand Down Expand Up @@ -381,6 +435,59 @@ void gostdecrypt(gost_ctx * c, const byte * in, byte * out)
out[7] = (byte) (n1 >> 24);
}

/* Low-level decryption routine. Decrypts one 64-bit block */
void magmadecrypt(gost_ctx * c, const byte * in, byte * out)
{
register word32 n1, n2; /* As named in the GOST */
n1 = in[7-0] | (in[7-1] << 8) | (in[7-2] << 16) | ((word32) in[7-3] << 24);
n2 = in[7-4] | (in[7-5] << 8) | (in[7-6] << 16) | ((word32) in[7-7] << 24);

n2 ^= f(c, n1 + c->key[0] + c->mask[0]);
n1 ^= f(c, n2 + c->key[1] + c->mask[1]);
n2 ^= f(c, n1 + c->key[2] + c->mask[2]);
n1 ^= f(c, n2 + c->key[3] + c->mask[3]);
n2 ^= f(c, n1 + c->key[4] + c->mask[4]);
n1 ^= f(c, n2 + c->key[5] + c->mask[5]);
n2 ^= f(c, n1 + c->key[6] + c->mask[6]);
n1 ^= f(c, n2 + c->key[7] + c->mask[7]);

n2 ^= f(c, n1 + c->key[7] + c->mask[7]);
n1 ^= f(c, n2 + c->key[6] + c->mask[6]);
n2 ^= f(c, n1 + c->key[5] + c->mask[5]);
n1 ^= f(c, n2 + c->key[4] + c->mask[4]);
n2 ^= f(c, n1 + c->key[3] + c->mask[3]);
n1 ^= f(c, n2 + c->key[2] + c->mask[2]);
n2 ^= f(c, n1 + c->key[1] + c->mask[1]);
n1 ^= f(c, n2 + c->key[0] + c->mask[0]);

n2 ^= f(c, n1 + c->key[7] + c->mask[7]);
n1 ^= f(c, n2 + c->key[6] + c->mask[6]);
n2 ^= f(c, n1 + c->key[5] + c->mask[5]);
n1 ^= f(c, n2 + c->key[4] + c->mask[4]);
n2 ^= f(c, n1 + c->key[3] + c->mask[3]);
n1 ^= f(c, n2 + c->key[2] + c->mask[2]);
n2 ^= f(c, n1 + c->key[1] + c->mask[1]);
n1 ^= f(c, n2 + c->key[0] + c->mask[0]);

n2 ^= f(c, n1 + c->key[7] + c->mask[7]);
n1 ^= f(c, n2 + c->key[6] + c->mask[6]);
n2 ^= f(c, n1 + c->key[5] + c->mask[5]);
n1 ^= f(c, n2 + c->key[4] + c->mask[4]);
n2 ^= f(c, n1 + c->key[3] + c->mask[3]);
n1 ^= f(c, n2 + c->key[2] + c->mask[2]);
n2 ^= f(c, n1 + c->key[1] + c->mask[1]);
n1 ^= f(c, n2 + c->key[0] + c->mask[0]);

out[7-0] = (byte) (n2 & 0xff);
out[7-1] = (byte) ((n2 >> 8) & 0xff);
out[7-2] = (byte) ((n2 >> 16) & 0xff);
out[7-3] = (byte) (n2 >> 24);
out[7-4] = (byte) (n1 & 0xff);
out[7-5] = (byte) ((n1 >> 8) & 0xff);
out[7-6] = (byte) ((n1 >> 16) & 0xff);
out[7-7] = (byte) (n1 >> 24);
}


/* Encrypts several blocks in ECB mode */
void gost_enc(gost_ctx * c, const byte * clear, byte * cipher, int blocks)
Expand Down
4 changes: 4 additions & 0 deletions gost89.h
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Original file line number Diff line number Diff line change
Expand Up @@ -59,6 +59,10 @@ void gost_dec_cfb(gost_ctx * ctx, const byte * iv, const byte * cipher,
void gostcrypt(gost_ctx * c, const byte * in, byte * out);
/* Decrypt one block */
void gostdecrypt(gost_ctx * c, const byte * in, byte * out);
/* Encrypt one block */
void magmacrypt(gost_ctx * c, const byte * in, byte * out);
/* Decrypt one block */
void magmadecrypt(gost_ctx * c, const byte * in, byte * out);
/* Set key into context */
void gost_key(gost_ctx * c, const byte * k);
/* Set key into context without key mask */
Expand Down
34 changes: 10 additions & 24 deletions gost_crypt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -607,27 +607,20 @@ static int magma_cipher_do_cbc(EVP_CIPHER_CTX *ctx, unsigned char *out,
while (inl > 0) {

for (i = 0; i < 8; i++) {
b[7 - i] = iv[i] ^ in_ptr[i];
}
gostcrypt(&(c->cctx), b, d);

for (i = 0; i < 8; i++) {
out_ptr[7 - i] = d[i];
out_ptr[i] = iv[i] ^ in_ptr[i];
}
magmacrypt(&(c->cctx), out_ptr, out_ptr);
memcpy(iv, out_ptr, 8);
out_ptr += 8;
in_ptr += 8;
inl -= 8;
}
} else {
while (inl > 0) {
for (i = 0; i < 8; i++) {
d[7 - i] = in_ptr[i];
}
gostdecrypt(&(c->cctx), d, b);
magmadecrypt(&(c->cctx), in_ptr, b);
memcpy(d, in_ptr, 8);
for (i = 0; i < 8; i++) {
out_ptr[i] = iv[i] ^ b[7 - i];
out_ptr[i] = iv[i] ^ b[i];
}
memcpy(iv, d, 8);
out_ptr += 8;
Expand Down Expand Up @@ -667,10 +660,9 @@ static int magma_cipher_do_ctr(EVP_CIPHER_CTX *ctx, unsigned char *out,
unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
unsigned int num = EVP_CIPHER_CTX_num(ctx);
size_t blocks, i, lasted = inl;
unsigned char b[8];
/* Process partial blocks */
while ((num & MAGMA_BLOCK_MASK) && lasted) {
*out_ptr++ = *in_ptr++ ^ buf[7 - (num & MAGMA_BLOCK_MASK)];
*out_ptr++ = *in_ptr++ ^ buf[num & MAGMA_BLOCK_MASK];
--lasted;
num++;
}
Expand All @@ -679,12 +671,9 @@ static int magma_cipher_do_ctr(EVP_CIPHER_CTX *ctx, unsigned char *out,
/* Process full blocks */
for (i = 0; i < blocks; i++) {
apply_acpkm_magma(c, &num);
magmacrypt(&(c->cctx), iv, buf);
for (j = 0; j < 8; j++) {
b[7 - j] = iv[j];
}
gostcrypt(&(c->cctx), b, buf);
for (j = 0; j < 8; j++) {
out_ptr[j] = buf[7 - j] ^ in_ptr[j];
out_ptr[j] = buf[j] ^ in_ptr[j];
}
ctr64_inc(iv);
c->count += MAGMA_BLOCK_SIZE;
Expand All @@ -697,15 +686,12 @@ static int magma_cipher_do_ctr(EVP_CIPHER_CTX *ctx, unsigned char *out,
/* Process the rest of plaintext */
if (lasted > 0) {
apply_acpkm_magma(c, &num);
for (j = 0; j < 8; j++) {
b[7 - j] = iv[j];
}
gostcrypt(&(c->cctx), b, buf);
magmacrypt(&(c->cctx), iv, buf);

for (i = 0; i < lasted; i++)
out_ptr[i] = buf[7 - i] ^ in_ptr[i];
out_ptr[i] = buf[i] ^ in_ptr[i];
ctr64_inc(iv);
c->count += j;
c->count += 8;
num += lasted;
}
EVP_CIPHER_CTX_set_num(ctx, num);
Expand Down

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