void SrtpSymCrypto::encrypt(const uint8_t* input, uint8_t* output ) {
if (algorithm == SrtpEncryptionAESCM || algorithm == SrtpEncryptionAESF8) {
AES_encrypt(input, output, (AES_KEY *)key);
}
else if (algorithm == SrtpEncryptionTWOCM || algorithm == SrtpEncryptionTWOF8) {
Twofish_encrypt((Twofish_key*)key, (Twofish_Byte*)input,
(Twofish_Byte*)output);
}
}
int CTwofish::padEncrypt(RD_UINT8 *pInput, int nInputOctets, RD_UINT8 *pOutBuffer)
{
int i, numBlocks, padLen;
RD_UINT8 block[16], *iv;
ASSERT((pInput != NULL) && (nInputOctets != NULL) && (pOutBuffer != NULL));
if((pInput == NULL) || (nInputOctets <= 0) || (pOutBuffer == NULL)) return 0;
numBlocks = nInputOctets / 16;
iv = m_pInitVector;
for(i = numBlocks; i > 0; i--)
{
((RD_UINT32*)block)[0] = ((RD_UINT32*)pInput)[0] ^ ((RD_UINT32*)iv)[0];
((RD_UINT32*)block)[1] = ((RD_UINT32*)pInput)[1] ^ ((RD_UINT32*)iv)[1];
((RD_UINT32*)block)[2] = ((RD_UINT32*)pInput)[2] ^ ((RD_UINT32*)iv)[2];
((RD_UINT32*)block)[3] = ((RD_UINT32*)pInput)[3] ^ ((RD_UINT32*)iv)[3];
Twofish_encrypt(&m_key, (Twofish_Byte *)block, (Twofish_Byte *)pOutBuffer);
iv = pOutBuffer;
pInput += 16;
pOutBuffer += 16;
}
padLen = 16 - (nInputOctets - (16 * numBlocks));
for (i = 0; i < 16 - padLen; i++)
{
block[i] = (RD_UINT8)(pInput[i] ^ iv[i]);
}
for (i = 16 - padLen; i < 16; i++)
{
block[i] = (RD_UINT8)((RD_UINT8)padLen ^ iv[i]);
}
Twofish_encrypt(&m_key, (Twofish_Byte *)block, (Twofish_Byte *)pOutBuffer);
return 16 * (numBlocks + 1);
}
void Twofish_cfb128_decrypt(Twofish_key* keyCtx, Twofish_Byte* in,
Twofish_Byte* out, size_t len,
Twofish_Byte* ivec, int32_t *num)
{
uint32_t n;
n = *num;
do {
while (n && len) {
unsigned char c;
*(out++) = ivec[n] ^ (c = *(in++)); ivec[n] = c;
--len;
n = (n+1) % 16;
}
while (len>=16) {
Twofish_encrypt(keyCtx, ivec, ivec);
for (n=0; n<16; n+=sizeof(size_t)) {
size_t t = *(size_t*)(in+n);
*(size_t*)(out+n) = *(size_t*)(ivec+n) ^ t;
*(size_t*)(ivec+n) = t;
}
len -= 16;
out += 16;
in += 16;
}
n = 0;
if (len) {
Twofish_encrypt(keyCtx, ivec, ivec);
while (len--) {
unsigned char c;
out[n] = ivec[n] ^ (c = in[n]); ivec[n] = c;
++n;
}
}
*num = n;
return;
} while (0);
}