我只想使用这 3 种模式从 openSSL 测试 AES: key 长度为 128,192 和 256，但我的解密文本与我的输入不同，我不知道为什么。此外，当我传递一个巨大的输入长度(比如说 1024 字节)时，我的程序显示 core dumped...我的输入总是相同的，但这并不重要，至少现在是这样。继承人的代码:

#include 
#include 
#include 
#include 

int main(int argc, char **argv)
{
    số nguyên i;
    int keylength;
    printf("Give a key length [only 128 or 192 or 256!]:\n");
    scanf("%d", &keylength);

    /* generate a key with a given length */
    unsigned char aes_key[keylength];
    memset(aes_key, 0, sizeof(aes_key));
    if (!RAND_bytes(aes_key, keylength))
    {
        exit(-1);
    }
    aes_key[keylength-1] = '\0';

    int inputslength;
    printf("Give an input's length:\n");
    scanf("%d", &inputslength);

    /* generate input with a given length */
    unsigned char aes_input[inputslength+1];
    memset(aes_input, '0', sizeof(aes_input));
    aes_input[inputslength] = '\0';

    /*printf("original:\t");
    for(i=0; i
    {
        printf("%c ", aes_input[i]);
    }
    printf("\n");*/

    /* init vector */
    unsigned char iv[AES_BLOCK_SIZE];
    if (!RAND_bytes(iv, AES_BLOCK_SIZE))
    {
        exit(-1);
    }

    //printf("AES_BLOCK_SIZE = %d\n", AES_BLOCK_SIZE); // aes block size is 16 bytes = 128 bits
    AES_KEY enc_key, dec_key;
    unsigned char enc_out[AES_BLOCK_SIZE];
    unsigned char dec_out[AES_BLOCK_SIZE];

    // so i can do with this aes-cbc-128 aes-cbc-192 aes-cbc-256
    AES_set_encrypt_key(aes_key, keylength, &enc_key);
    AES_cbc_encrypt(aes_input, enc_out, inputslength, &enc_key, iv, AES_ENCRYPT);

    AES_set_decrypt_key(aes_key, keylength, &dec_key);
    AES_decrypt(enc_out, dec_out, &dec_key);

    printf("original:\t");
    for(i=0;*(aes_input+i)!=0x00;i++)
        printf("%X ",*(aes_input+i));
    printf("\nencrypted:\t");

    for(i=0;*(enc_out+i)!=0x00;i++)
        printf("%X ",*(enc_out+i));

    printf("\ndecrypted:\t");
    for(i=0;*(dec_out+i)!=0x00;i++)
        printf("%X ",*(dec_out+i));
    inf("\n");

    /*printf("\n\noriginal:\t");
    for(i=0; i
    {
        printf("%x ", dec_out[i]);
    }
    printf("\n");*/


    trả về 0;
}

biên tập:

当我将输出大小更改为 inputslength thay vì AES_BLOCK_SIZE 时，我得到了结果:

Give a key length [only 128 or 192 or 256!]:
128
Give an input's length:
5
original: 30 30 30 30 30 
encrypted: 94 56 50 7E 19 B2 1C CE 20 23 4A E7 10 AF DB E3 30 30 30 30 30 
decrypted: E1 5F F4 3D E8 8D 91 19 CD 3E 22 1E AF 1C 8F 5A 94 56 50 7E 19 B2 1C CE 20 23 4A E7 10 AF DB E3 30 30 30 30 30

那么有没有可能是输出量和 iv 的大小有问题？它们应该具有什么大小(对于 AES-CBC-128、AES-CBC-192、AES-CBC-256)？

câu trả lời hay nhất

看一看您的代码的这个修改版本。请注意以下几点:

1. 添加了 hex_print(次要)
2. 添加了适当大小的键缓冲区(中等)。
3. 添加了适当大小的输出加密缓冲区(它必须是 block 大小的倍数，如果原始源缓冲区是精确的 block 大小倍数，您仍然需要一个完整的填充 block (有关更多信息，请参阅 PKCS 5 填充) .
4. 加密和解密使用相同的 IV。
5. 最后，AES_cbc_encrypt() dùng cho 加密和解密(请参阅调用中的最后一个参数)，这看起来很奇怪。

源代码

#include 
#include 
#include 
#include 
#include 

// a simple hex-print routine. could be modified to print 16 bytes-per-line
static void hex_print(const void* pv, size_t len)
{
    const unsigned char * p = (const unsigned char*)pv;
    if (NULL == pv)
        printf("NULL");
    khác
    {
        size_t i = 0;
        for (; i<>
            printf("%02X ", *p++);
    }
    inf("\n");
}

// main entrypoint
int main(int argc, char **argv)
{
    int keylength;
    printf("Give a key length [only 128 or 192 or 256!]:\n");
    scanf("%d", &keylength);

    /* generate a key with a given length */
    unsigned char aes_key[keylength/8];
    memset(aes_key, 0, keylength/8);
    if (!RAND_bytes(aes_key, keylength/8))
        exit(-1);

    size_t inputslength = 0;
    printf("Give an input's length:\n");
    scanf("%lu", &inputslength);

    /* generate input with a given length */
    unsigned char aes_input[inputslength];
    memset(aes_input, 'X', inputslength);

    /* init vector */
    unsigned char iv_enc[AES_BLOCK_SIZE], iv_dec[AES_BLOCK_SIZE];
    RAND_bytes(iv_enc, AES_BLOCK_SIZE);
    memcpy(iv_dec, iv_enc, AES_BLOCK_SIZE);

    // buffers for encryption and decryption
    const size_t encslength = ((inputslength + AES_BLOCK_SIZE) / AES_BLOCK_SIZE) * AES_BLOCK_SIZE;
    unsigned char enc_out[encslength];
    unsigned char dec_out[inputslength];
    memset(enc_out, 0, sizeof(enc_out));
    memset(dec_out, 0, sizeof(dec_out));

    // so i can do with this aes-cbc-128 aes-cbc-192 aes-cbc-256
    AES_KEY enc_key, dec_key;
    AES_set_encrypt_key(aes_key, keylength, &enc_key);
    AES_cbc_encrypt(aes_input, enc_out, inputslength, &enc_key, iv_enc, AES_ENCRYPT);

    AES_set_decrypt_key(aes_key, keylength, &dec_key);
    AES_cbc_encrypt(enc_out, dec_out, encslength, &dec_key, iv_dec, AES_DECRYPT);

    printf("original:\t");
    hex_print(aes_input, sizeof(aes_input));

    printf("encrypt:\t");
    hex_print(enc_out, sizeof(enc_out));

    printf("decrypt:\t");
    hex_print(dec_out, sizeof(dec_out));

    trả về 0;
}

测试输出

Give a key length [only 128 or 192 or 256!]:
128
Give an input's length:
10
original: 58 58 58 58 58 58 58 58 58 58 
encrypt: A9 66 C5 24 A4 02 AB 96 08 65 F7 22 A5 FB BE 26 
decrypt: 58 58 58 58 58 58 58 58 58 58 

第二个测试输出

Give a key length [only 128 or 192 or 256!]:
128
Give an input's length:
10
original: 58 58 58 58 58 58 58 58 58 58 
encrypt: C2 47 6D B1 A1 68 29 53 55 74 C5 CC 3F 27 0A 3F 
decrypt: 58 58 58 58 58 58 58 58 58 58 

我真诚地希望这对您有所帮助。

关于c - AES (aes-cbc-128, aes-cbc-192, aes-cbc-256) 加密/解密与 openssl C，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/18152913/