c - openssl C による AES (aes-ige-128、aes-ige-192、aes-ige-256) 暗号化/復号化

Question

最近、ようやく (stackoverflow のユーザー @WhozCraig の助けを借りて) AES を CBC モードで動作させることができました。今、私はまったく同じことをしたいと思いますが、AES IGE を使用します。私は見てopenssl-1.0.1e/test/igetest.c、自分のテストを構築しようとしました。しかし、繰り返しますが、入力と出力の適切なサイズに問題があります。以前のコードからコピーしたため、他のすべては良好です: AES (aes-cbc-128, aes-cbc-192, aes-cbc-256) 暗号化/復号化 with openssl C .

ここで、32 未満の入力長を渡すと、次のように表示されます。

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)

しかし、長さが 32 より大きい場合、すべてが問題ないかどうかもわかりません。

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 

コードは次のとおりです。

    #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;
}

最後に！うまくいきました (そう願っています)。しかし、以下のこのコードは 100% 良いと誰かが言うことができれば、私は非常に感謝しています;)

#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;
}

私はこれだけを変更しました：

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

それに：

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

それが正しいか？

編集番号2 ;)

わかりました、あなたのアドバイスで入力にパディングを追加して、別の例を行いました。今は大丈夫ですか？

#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;
}