diff options
Diffstat (limited to 'libtomcrypt/src/modes/ctr/ctr_encrypt.c')
| -rw-r--r-- | libtomcrypt/src/modes/ctr/ctr_encrypt.c | 93 |
1 files changed, 60 insertions, 33 deletions
diff --git a/libtomcrypt/src/modes/ctr/ctr_encrypt.c b/libtomcrypt/src/modes/ctr/ctr_encrypt.c index 7319cf5..eb7328c 100644 --- a/libtomcrypt/src/modes/ctr/ctr_encrypt.c +++ b/libtomcrypt/src/modes/ctr/ctr_encrypt.c @@ -17,47 +17,17 @@ #ifdef LTC_CTR_MODE /** - CTR encrypt + CTR encrypt software implementation @param pt Plaintext @param ct [out] Ciphertext @param len Length of plaintext (octets) @param ctr CTR state @return CRYPT_OK if successful */ -int ctr_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_CTR *ctr) +static int _ctr_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_CTR *ctr) { int x, err; - LTC_ARGCHK(pt != NULL); - LTC_ARGCHK(ct != NULL); - LTC_ARGCHK(ctr != NULL); - - if ((err = cipher_is_valid(ctr->cipher)) != CRYPT_OK) { - return err; - } - - /* is blocklen/padlen valid? */ - if (ctr->blocklen < 1 || ctr->blocklen > (int)sizeof(ctr->ctr) || - ctr->padlen < 0 || ctr->padlen > (int)sizeof(ctr->pad)) { - return CRYPT_INVALID_ARG; - } - -#ifdef LTC_FAST - if (ctr->blocklen % sizeof(LTC_FAST_TYPE)) { - return CRYPT_INVALID_ARG; - } -#endif - - /* handle acceleration only if pad is empty, accelerator is present and length is >= a block size */ - if ((ctr->padlen == ctr->blocklen) && cipher_descriptor[ctr->cipher].accel_ctr_encrypt != NULL && (len >= (unsigned long)ctr->blocklen)) { - if ((err = cipher_descriptor[ctr->cipher].accel_ctr_encrypt(pt, ct, len/ctr->blocklen, ctr->ctr, ctr->mode, &ctr->key)) != CRYPT_OK) { - return err; - } - pt += (len / ctr->blocklen) * ctr->blocklen; - ct += (len / ctr->blocklen) * ctr->blocklen; - len %= ctr->blocklen; - } - while (len) { /* is the pad empty? */ if (ctr->padlen == ctr->blocklen) { @@ -87,7 +57,7 @@ int ctr_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, s ctr->padlen = 0; } #ifdef LTC_FAST - if (ctr->padlen == 0 && len >= (unsigned long)ctr->blocklen) { + if ((ctr->padlen == 0) && (len >= (unsigned long)ctr->blocklen)) { for (x = 0; x < ctr->blocklen; x += sizeof(LTC_FAST_TYPE)) { *(LTC_FAST_TYPE_PTR_CAST((unsigned char *)ct + x)) = *(LTC_FAST_TYPE_PTR_CAST((unsigned char *)pt + x)) ^ *(LTC_FAST_TYPE_PTR_CAST((unsigned char *)ctr->pad + x)); @@ -105,6 +75,63 @@ int ctr_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, s return CRYPT_OK; } +/** + CTR encrypt + @param pt Plaintext + @param ct [out] Ciphertext + @param len Length of plaintext (octets) + @param ctr CTR state + @return CRYPT_OK if successful +*/ +int ctr_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_CTR *ctr) +{ + int err, fr; + + LTC_ARGCHK(pt != NULL); + LTC_ARGCHK(ct != NULL); + LTC_ARGCHK(ctr != NULL); + + if ((err = cipher_is_valid(ctr->cipher)) != CRYPT_OK) { + return err; + } + + /* is blocklen/padlen valid? */ + if ((ctr->blocklen < 1) || (ctr->blocklen > (int)sizeof(ctr->ctr)) || + (ctr->padlen < 0) || (ctr->padlen > (int)sizeof(ctr->pad))) { + return CRYPT_INVALID_ARG; + } + +#ifdef LTC_FAST + if (ctr->blocklen % sizeof(LTC_FAST_TYPE)) { + return CRYPT_INVALID_ARG; + } +#endif + + /* handle acceleration only if pad is empty, accelerator is present and length is >= a block size */ + if ((cipher_descriptor[ctr->cipher].accel_ctr_encrypt != NULL) && (len >= (unsigned long)ctr->blocklen)) { + if (ctr->padlen < ctr->blocklen) { + fr = ctr->blocklen - ctr->padlen; + if ((err = _ctr_encrypt(pt, ct, fr, ctr)) != CRYPT_OK) { + return err; + } + pt += fr; + ct += fr; + len -= fr; + } + + if (len >= (unsigned long)ctr->blocklen) { + if ((err = cipher_descriptor[ctr->cipher].accel_ctr_encrypt(pt, ct, len/ctr->blocklen, ctr->ctr, ctr->mode, &ctr->key)) != CRYPT_OK) { + return err; + } + pt += (len / ctr->blocklen) * ctr->blocklen; + ct += (len / ctr->blocklen) * ctr->blocklen; + len %= ctr->blocklen; + } + } + + return _ctr_encrypt(pt, ct, len, ctr); +} + #endif /* ref: $Format:%D$ */ |