diff options
Diffstat (limited to 'providers/implementations/ciphers')
| -rw-r--r-- | providers/implementations/ciphers/cipher_cts.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/providers/implementations/ciphers/cipher_cts.c b/providers/implementations/ciphers/cipher_cts.c index 5732ae1990..cb3372c646 100644 --- a/providers/implementations/ciphers/cipher_cts.c +++ b/providers/implementations/ciphers/cipher_cts.c @@ -135,7 +135,7 @@ static void do_xor(const unsigned char *in1, const unsigned char *in2, static size_t cts128_cs1_decrypt(PROV_CIPHER_CTX *ctx, const unsigned char *in, unsigned char *out, size_t len) { - aligned_16bytes mid_iv, ct_mid, pt_last; + aligned_16bytes mid_iv, ct_mid, cn, pt_last; size_t residue; residue = len % CTS_BLOCK_SIZE; @@ -155,6 +155,8 @@ static size_t cts128_cs1_decrypt(PROV_CIPHER_CTX *ctx, const unsigned char *in, } /* Save the iv that will be used by the second last block */ memcpy(mid_iv.c, ctx->iv, CTS_BLOCK_SIZE); + /* Save the C(n) block */ + memcpy(cn.c, in + residue, CTS_BLOCK_SIZE); /* Decrypt the last block first using an iv of zero */ memset(ctx->iv, 0, CTS_BLOCK_SIZE); @@ -179,6 +181,7 @@ static size_t cts128_cs1_decrypt(PROV_CIPHER_CTX *ctx, const unsigned char *in, /* Restore the iv needed by the second last block */ memcpy(ctx->iv, mid_iv.c, CTS_BLOCK_SIZE); + /* * Decrypt the second last plaintext block now that we have rebuilt the * ciphertext. @@ -186,6 +189,8 @@ static size_t cts128_cs1_decrypt(PROV_CIPHER_CTX *ctx, const unsigned char *in, if (!ctx->hw->cipher(ctx, out, ct_mid.c, CTS_BLOCK_SIZE)) return 0; + /* The returned iv is the C(n) block */ + memcpy(ctx->iv, cn.c, CTS_BLOCK_SIZE); return len + CTS_BLOCK_SIZE + residue; } @@ -232,7 +237,7 @@ static size_t cts128_cs3_encrypt(PROV_CIPHER_CTX *ctx, const unsigned char *in, static size_t cts128_cs3_decrypt(PROV_CIPHER_CTX *ctx, const unsigned char *in, unsigned char *out, size_t len) { - aligned_16bytes mid_iv, ct_mid, pt_last; + aligned_16bytes mid_iv, ct_mid, cn, pt_last; size_t residue; if (len < CTS_BLOCK_SIZE) /* CS3 requires at least one block */ @@ -256,8 +261,10 @@ static size_t cts128_cs3_decrypt(PROV_CIPHER_CTX *ctx, const unsigned char *in, } /* Save the iv that will be used by the second last block */ memcpy(mid_iv.c, ctx->iv, CTS_BLOCK_SIZE); + /* Save the C(n) block : For CS3 it is C(1)||...||C(n-2)||C(n)||C(n-1)* */ + memcpy(cn.c, in, CTS_BLOCK_SIZE); - /* Decrypt the Cn block first using an iv of zero */ + /* Decrypt the C(n) block first using an iv of zero */ memset(ctx->iv, 0, CTS_BLOCK_SIZE); if (!ctx->hw->cipher(ctx, pt_last.c, in, CTS_BLOCK_SIZE)) return 0; @@ -288,6 +295,8 @@ static size_t cts128_cs3_decrypt(PROV_CIPHER_CTX *ctx, const unsigned char *in, if (!ctx->hw->cipher(ctx, out, ct_mid.c, CTS_BLOCK_SIZE)) return 0; + /* The returned iv is the C(n) block */ + memcpy(ctx->iv, cn.c, CTS_BLOCK_SIZE); return len + CTS_BLOCK_SIZE + residue; } |