AES (aes-ige-128, aes-ige-192, aes-ige-256) 使用 openssl C 加密/解密 [英] AES (aes-ige-128, aes-ige-192, aes-ige-256) encryption/decryption with openssl C

问题描述

最近我终于(在 stackoverflow 的用户 @WhozCraig 的帮助下)开始在 CBC 模式下使用 AES.现在，我想做完全相同的事情，但使用 AES IGE.我查看了 openssl-1.0.1e/test/igetest.c 并尝试构建我自己的测试.但再一次，我对输入和输出的大小有问题.其他一切都很好，因为我从以前的代码中复制了它:AES (aes-cbc-128, aes-cbc-192, aes-cbc-256) 使用 openssl C 加密/解密.

Recently I finally (with help of stackoverflow's user, @WhozCraig) got to work AES in CBC mode. Now, I would like to do exact same thing but with AES IGE. I took a look at openssl-1.0.1e/test/igetest.c and tried to build my own test. But once again, I have a problem with inputs and outputs proper sizes. Everything else is good, because I copied it from my previous code: AES (aes-cbc-128, aes-cbc-192, aes-cbc-256) encryption/decryption with openssl C.

现在，当我传递一个小于 32 的输入长度时，它说:

Now, when I pass an inputs length which is less than 32, it says:

Give a key length [only 128 or 192 or 256!]:
256
Give an input's length:
3
aes_ige.c(88): OpenSSL internal error, assertion failed: (length%AES_BLOCK_SIZE) == 0
 (core dumped)

但是当长度大于 32 时，我也不太确定是否一切正常:

But when the lenght is bigger than 32, Im also not so sure if its all ok:

Give a key length [only 128 or 192 or 256!]:
256
Give an input's length:
48
original:       58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 
encrypt:        A4 1F C4 E8 42 5E E5 62 1A B6 C1 47 D2 2F 8D 98 D0 0B 32 77 4E 36 84 25 15 5B BA 60 EA A9 64 D2 53 D1 98 78 83 21 90 90 74 44 C7 AA 3E AD 9B 26 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
decrypt:        58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 

代码如下:

    #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/aes.h>
#include <openssl/rand.h>

// 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");
    else
    {
        size_t i = 0;
        for (; i<len;++i)
            printf("%02X ", *p++);
    }
    printf("\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);

    const size_t ivsize = AES_BLOCK_SIZE*2;

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

    // buffers for encryption and decryption
    const size_t encslength = (inputslength/AES_BLOCK_SIZE + 1) * AES_BLOCK_SIZE;//((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));

    AES_KEY enc_key, dec_key;
    AES_set_encrypt_key(aes_key, keylength, &enc_key);
    AES_set_decrypt_key(aes_key, keylength, &dec_key);

    AES_ige_encrypt(aes_input, enc_out, inputslength, &enc_key, iv_enc, AES_ENCRYPT);

    AES_ige_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));

    return 0;
}

终于！成功了(希望如此).但如果有人能说下面的代码 100% 好，我将不胜感激；)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/aes.h>
#include <openssl/rand.h>

// 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");
    else
    {
        size_t i = 0;
        for (; i<len;++i)
            printf("%02X ", *p++);
    }
    printf("\n");
}

// main entrypoint
int main(int argc, char **argv)
{
    int keylength = 256;
    //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);

    const size_t ivsize = AES_BLOCK_SIZE*2;
    /* init vector */
    unsigned char iv_enc[ivsize], iv_dec[ivsize];
    RAND_bytes(iv_enc, ivsize);
    memcpy(iv_dec, iv_enc, ivsize);

    // 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_ige_encrypt(aes_input, enc_out, encslength, &enc_key, iv_enc, AES_ENCRYPT);

    AES_set_decrypt_key(aes_key, keylength, &dec_key);
    AES_ige_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));

    return 0;
}

我只改变了这个:

AES_ige_encrypt(aes_input, enc_out, **inputslength**, &enc_key, iv_enc, AES_ENCRYPT);

进入:

AES_ige_encrypt(aes_input, enc_out, **encslength**, &enc_key, iv_enc, AES_ENCRYPT);

正确吗?

编辑第 2 号 ;)

好吧，伙计们，又举了一个例子，你的建议为输入添加了一些填充.希望现在可以了吗?

Ok guys, did another example, with your advices added some padding to the input. Hope its ok now?

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/aes.h>
#include <openssl/rand.h>

// 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");
    else
    {
        size_t i = 0;
        for (; i<len;++i)
            printf("%02X ", *p++);
    }
    printf("\n");
}

// main entrypoint
int main(int argc, char **argv)
{
    int keylength = 256;
    //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);

    const size_t ivsize = AES_BLOCK_SIZE*2;
    /* init vector */
    unsigned char iv_enc[ivsize], iv_dec[ivsize];
    RAND_bytes(iv_enc, ivsize);
    memcpy(iv_dec, iv_enc, ivsize);

    // buffers for encryption and decryption
    const size_t encslength = ((inputslength + AES_BLOCK_SIZE) / AES_BLOCK_SIZE) * AES_BLOCK_SIZE;

    unsigned char paddedinput[encslength];
    memset(paddedinput, 0, encslength);
    memcpy(paddedinput, aes_input, inputslength);

    unsigned char enc_out[encslength];
    unsigned char dec_out[inputslength];
    memset(enc_out, 0, sizeof(enc_out));
    memset(dec_out, 0, sizeof(dec_out));

    AES_KEY enc_key, dec_key;
    AES_set_encrypt_key(aes_key, keylength, &enc_key);
    AES_ige_encrypt(paddedinput, enc_out, encslength, &enc_key, iv_enc, AES_ENCRYPT);

    AES_set_decrypt_key(aes_key, keylength, &dec_key);
    AES_ige_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));

    return 0;
}

推荐答案

错误信息说明了一切.

aes_ige.c(88): OpenSSL internal error, assertion failed: (length%AES_BLOCK_SIZE) == 0

这基本上是一个运行时检查(断言)，由于提供给函数 AES_ige_encrypt() 的无效输入而失败，="http://fossies.org/dox/openssl-1.0.1e/aes__ige_8c_source.html#l00088" rel="noreferrer">aes_ige.c 的第 88 行.

This is basically a run-time-check (assertion) that fails due to invalid input provided to the function AES_ige_encrypt() present in the source at line 88 of aes_ige.c.

OPENSSL_assert((length%AES_BLOCK_SIZE) == 0);

断言基本上检查length(传递给函数的第三个参数)是否是AES_BLOCK_SIZE的整数倍强>.如果是，则继续执行，否则程序停止并打印有关断言失败的警告.

The assertion basically checks if length (the 3rd parameter passed to the function) is an integral multiple of AES_BLOCK_SIZE. If yes, the execution continues, otherwise the program halts and prints warning about the assertion having failed.

1. 因此请确保传递给 AES_ige_encrypt() 的数据大小是 AES_BLOCK_SIZE.

如果数据的大小不是整数倍，则在其后面追加NUL个字节，使总大小成为<的最接近的倍数代码>AES_BLOCK_SIZE.

If size of the data is not an integral multiple, then append NUL bytes to it to make the total size the nearest multiple of AES_BLOCK_SIZE.

此外，始终将integral-multiple-of-AES_BLOCK_SIZE"值作为长度传递strong> 参数到 AES_ige_encrypt().

Also, always pass the "integral-multiple-of-AES_BLOCK_SIZE" value as the length parameter to AES_ige_encrypt().

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