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initial cfb1/cfb8 support added

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This commit is contained in:
Jacob Barthelmeh
2020-01-29 09:59:51 -07:00
committed by Eric Blankenhorn
parent 9c4e0807e2
commit 9d61ba6c62
3 changed files with 355 additions and 1 deletions
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192
wolfcrypt/src/aes.c
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@@ -7476,6 +7476,196 @@ int wc_AesCfbDecrypt(Aes* aes, byte* out, const byte* in, word32 sz)
return wc_AesFeedbackDecrypt(aes, out, in, sz, AES_CFB_MODE);
}
#endif /* HAVE_AES_DECRYPT */
/* shift the whole AES_BLOCK_SIZE array left by 8 or 1 bits */
static void shiftLeftArray(byte* ary, byte shift)
{
int i;
if (shift == WOLFSSL_BIT_SIZE) {
/* shifting over by 8 bits */
for (i = 0; i < AES_BLOCK_SIZE - 1; i++) {
ary[i] = ary[i+1];
}
ary[i] = 0;
}
else {
byte carry = 0;
/* shifting over by 7 or less bits */
for (i = 0; i < AES_BLOCK_SIZE - 1; i++) {
carry = ary[i+1] & (0XFF << (WOLFSSL_BIT_SIZE - shift));
carry >>= (WOLFSSL_BIT_SIZE - shift);
ary[i] = (ary[i] << shift) + carry;
}
ary[i] = ary[i] << shift;
}
}
/* returns 0 on success and negative values on failure */
static int wc_AesFeedbackCFB8(Aes* aes, byte* out, const byte* in,
word32 sz, byte dir)
{
byte *pt;
if (aes == NULL || out == NULL || in == NULL) {
return BAD_FUNC_ARG;
}
while (sz > 0) {
wc_AesEncryptDirect(aes, (byte*)aes->tmp, (byte*)aes->reg);
if (dir == AES_DECRYPTION) {
pt = (byte*)aes->reg;
/* LSB + CAT */
shiftLeftArray(pt, WOLFSSL_BIT_SIZE);
pt[AES_BLOCK_SIZE - 1] = in[0];
}
/* MSB + XOR */
out[0] = aes->tmp[0] ^ in[0];
if (dir == AES_ENCRYPTION) {
pt = (byte*)aes->reg;
/* LSB + CAT */
shiftLeftArray(pt, WOLFSSL_BIT_SIZE);
pt[AES_BLOCK_SIZE - 1] = out[0];
}
out += 1;
in += 1;
sz -= 1;
}
return 0;
}
/* returns 0 on success and negative values on failure */
static int wc_AesFeedbackCFB1(Aes* aes, byte* out, const byte* in,
word32 sz, byte dir)
{
byte tmp;
byte* pt;
int bit = 7;
if (aes == NULL || out == NULL || in == NULL) {
return BAD_FUNC_ARG;
}
out[0] = 0;
while (sz > 0) {
wc_AesEncryptDirect(aes, (byte*)aes->tmp, (byte*)aes->reg);
if (dir == AES_DECRYPTION) {
pt = (byte*)aes->reg;
/* LSB + CAT */
tmp = (0X01 << bit) & in[0];
tmp = tmp >> bit;
shiftLeftArray((byte*)aes->reg, 1);
pt[AES_BLOCK_SIZE - 1] |= tmp;
}
/* MSB + XOR */
tmp = (0X01 << bit) & in[0];
pt = (byte*)aes->tmp;
tmp = pt[0] ^ (tmp >> bit);
tmp &= 0x01;
out[0] |= (tmp << bit);
if (dir == AES_ENCRYPTION) {
pt = (byte*)aes->reg;
/* LSB + CAT */
shiftLeftArray((byte*)aes->reg, 1);
pt[AES_BLOCK_SIZE - 1] |= tmp;
}
bit--;
if (bit < 0) {
out += 1;
in += 1;
sz -= 1;
bit = 7;
if (sz > 0) {
out[0] = 0;
}
}
else {
sz -= 1;
}
}
return 0;
}
/* CFB 1
*
* aes structure holding key to use for encryption
* out buffer to hold result of encryption (must be at least as large as input
* buffer)
* in buffer to encrypt
* sz size of input buffer
*
* returns 0 on success and negative values on failure
*/
int wc_AesCfb1Encrypt(Aes* aes, byte* out, const byte* in, word32 sz)
{
return wc_AesFeedbackCFB1(aes, out, in, sz, AES_ENCRYPTION);
}
/* CFB 8
*
* aes structure holding key to use for encryption
* out buffer to hold result of encryption (must be at least as large as input
* buffer)
* in buffer to encrypt
* sz size of input buffer
*
* returns 0 on success and negative values on failure
*/
int wc_AesCfb8Encrypt(Aes* aes, byte* out, const byte* in, word32 sz)
{
return wc_AesFeedbackCFB8(aes, out, in, sz, AES_ENCRYPTION);
}
#ifdef HAVE_AES_DECRYPT
/* CFB 1
*
* aes structure holding key to use for encryption
* out buffer to hold result of encryption (must be at least as large as input
* buffer)
* in buffer to encrypt
* sz size of input buffer
*
* returns 0 on success and negative values on failure
*/
int wc_AesCfb1Decrypt(Aes* aes, byte* out, const byte* in, word32 sz)
{
return wc_AesFeedbackCFB1(aes, out, in, sz, AES_DECRYPTION);
}
/* CFB 8
*
* aes structure holding key to use for encryption
* out buffer to hold result of encryption (must be at least as large as input
* buffer)
* in buffer to encrypt
* sz size of input buffer
*
* returns 0 on success and negative values on failure
*/
int wc_AesCfb8Decrypt(Aes* aes, byte* out, const byte* in, word32 sz)
{
return wc_AesFeedbackCFB8(aes, out, in, sz, AES_DECRYPTION);
}
#endif /* HAVE_AES_DECRYPT */
#endif /* WOLFSSL_AES_CFB */
#ifdef WOLFSSL_AES_OFB
@@ -7513,7 +7703,7 @@ int wc_AesOfbDecrypt(Aes* aes, byte* out, const byte* in, word32 sz)
return wc_AesFeedbackDecrypt(aes, out, in, sz, AES_OFB_MODE);
}
#endif /* HAVE_AES_DECRYPT */
#endif /* WOLFSSL_AES_CFB */
#endif /* WOLFSSL_AES_OFB */
#ifdef HAVE_AES_KEYWRAP