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/**
* \file
* \author Egor Tensin <Egor.Tensin@gmail.com>
* \date 2015
* \copyright This file is licensed under the terms of the MIT License.
* See LICENSE.txt for details.
*/
#include <aesni/all.h>
#include <stdlib.h>
#include <string.h>
static unsigned char FULL_BLOCK_PADDING[16] = { 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16 };
AesNI_StatusCode aesni_encrypt_buffer_ecb128(
const void* src,
size_t src_size,
void* dest,
size_t* dest_size,
AesNI_Aes128_RoundKeys* encryption_keys,
AesNI_ErrorDetails* err_details)
{
if (dest_size == NULL)
return aesni_make_null_argument_error(err_details, "dest_size");
const size_t rem_size = src_size % 16;
const size_t padding_size = 16 - rem_size;
*dest_size = src_size + padding_size;
if (dest == NULL)
return AESNI_SUCCESS;
if (src == NULL)
return aesni_make_null_argument_error(err_details, "src");
if (encryption_keys == NULL)
return aesni_make_null_argument_error(err_details, "encryption_keys");
const size_t src_len = src_size / 16;
for (size_t i = 0; i < src_len; ++i, (char*) src += 16, (char*) dest += 16)
{
AesNI_Block128 plaintext = aesni_load_block128(src);
AesNI_Block128 ciphertext = aesni_aes128_encrypt_block_ecb(plaintext, encryption_keys);
aesni_store_block128(dest, ciphertext);
}
unsigned char padding[16];
if (rem_size == 0)
{
memcpy(padding, FULL_BLOCK_PADDING, 16);
}
else
{
memcpy(padding, src, rem_size);
memset(padding + rem_size, padding_size, padding_size);
}
AesNI_Block128 plaintext = aesni_load_block128(padding);
AesNI_Block128 ciphertext = aesni_aes128_encrypt_block_ecb(plaintext, encryption_keys);
aesni_store_block128(dest, ciphertext);
return AESNI_SUCCESS;
}
static unsigned char get_pkcs7_padding_size(const unsigned char* padding)
{
if (padding[15] < 0x01 || padding[15] > 0x10)
return 0;
for (int i = 16 - padding[15]; i < 15; ++i)
if (padding[i] != padding[15])
return 0;
return padding[15];
}
AesNI_StatusCode aesni_decrypt_buffer_ecb128(
const void* src,
size_t src_size,
void* dest,
size_t* dest_size,
AesNI_Aes128_RoundKeys* decryption_keys,
AesNI_ErrorDetails* err_details)
{
if (dest_size == NULL)
return aesni_make_null_argument_error(err_details, "dest_size");
*dest_size = src_size;
if (dest == NULL)
return 0;
if (src == NULL)
return aesni_make_null_argument_error(err_details, "src");
if (decryption_keys == NULL)
return aesni_make_null_argument_error(err_details, "decryption_keys");
const size_t src_len = src_size / 16;
for (size_t i = 0; i < src_len - 1; ++i, (char*) src += 16, (char*) dest += 16)
{
AesNI_Block128 ciphertext = aesni_load_block128(src);
AesNI_Block128 plaintext = aesni_aes128_decrypt_block_ecb(ciphertext, decryption_keys);
aesni_store_block128(dest, plaintext);
}
AesNI_Block128 ciphertext = aesni_load_block128(src);
AesNI_Block128 plaintext = aesni_aes128_decrypt_block_ecb(ciphertext, decryption_keys);
unsigned char padding[16];
aesni_store_block128(padding, plaintext);
unsigned char padding_size = get_pkcs7_padding_size(padding);
if (padding_size == 0)
return aesni_make_invalid_pkcs7_padding_error(err_details);
memcpy(dest, padding, 16 - padding_size);
*dest_size -= padding_size;
return AESNI_SUCCESS;
}
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