libgcrypt中的AES128未加密

Question

我一直在为我的一个小型加密项目尝试libgcrypt，但我似乎无法正确实现en/解密。以下是类及其用法。

#include <iostream>
#include <string>
#include <cstdlib>
#include <gcrypt.h>
#include "aes.h"
#define GCRY_CIPHER GCRY_CIPHER_AES128   
#define GCRY_MODE GCRY_CIPHER_MODE_ECB 
using namespace std;
aes::aes(string a) {
    key = a;
    keyLength = gcry_cipher_get_algo_keylen(GCRY_CIPHER);
    gcry_control (GCRYCTL_DISABLE_SECMEM, 0);
    gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
    gcry_cipher_open(&handle, GCRY_CIPHER, GCRY_MODE, 0);
    gcry_cipher_setkey(handle, key.c_str(), keyLength);
}
string aes::encrypt(string text) {
    size_t textLength = text.size() + 1;
    char * encBuffer = (char *)malloc(textLength);
    gcry_cipher_encrypt(handle, encBuffer, textLength, text.c_str(), textLength);
    string ret (encBuffer);
    return ret;
}
string aes::decrypt(string text) {
    size_t textLength = text.size() + 1;
    char * decBuffer = (char * )malloc(textLength);
    gcry_cipher_decrypt(handle, decBuffer, textLength, text.c_str(), textLength);
    string ret (decBuffer);
    return ret;
}

我在一个主要功能中使用它，比如：

...
aes bb = aes("one test AES key");
string test = "Some Message";
string enc = bb.encrypt(test);
string dec = bb.decrypt(enc);
for (size_t index = 0; index<enc.size(); index++)
    printf("%c", enc[index]);
printf("n");
cout << dec << endl;
...

输出为

BBBBBBBBBBBBB
�n�S[

奇怪的是，我用几乎完全相同的语句制作了一个测试程序，它运行得很好。当我试着把它包装成一个班级时，它开始散开了。如果有人想看的话，下面是这个程序的代码。

#include <cstdlib>
#include <iostream>
#include <string>
#include <gcrypt.h>
using namespace std;
#define GCRY_CIPHER GCRY_CIPHER_AES128   // Pick the cipher here
#define GCRY_MODE GCRY_CIPHER_MODE_ECB // Pick the cipher mode here
void aesTest(void)
{
    gcry_cipher_hd_t handle;
    size_t keyLength = gcry_cipher_get_algo_keylen(GCRY_CIPHER);
    string txtBuffer ("123456789 abcdefghijklmnopqrstuvwzyz ABCDEFGHIJKLMNOPQRSTUVWZYZ");
    size_t txtLength = txtBuffer.size() +1; // string plus termination
    char * encBuffer = (char *)malloc(txtLength);
    char * outBuffer = (char *)malloc(txtLength);
    char * key = "one test AES key"; // 16 bytes
    gcry_control (GCRYCTL_DISABLE_SECMEM, 0);
    gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
    gcry_cipher_open(&handle, GCRY_CIPHER, GCRY_MODE, 0);
    gcry_cipher_setkey(handle, key, keyLength);
    gcry_cipher_encrypt(handle, encBuffer, txtLength, txtBuffer.c_str(), txtLength);
    gcry_cipher_decrypt(handle, outBuffer, txtLength, encBuffer, txtLength);
    size_t index;
    printf("encBuffer = ");
    for (index = 0; index<txtLength; index++)
        printf("%c", encBuffer[index]);
    printf("n");
    printf("outBuffer = %sn", outBuffer);
    gcry_cipher_close(handle);
    free(encBuffer);
    free(outBuffer);
}

int main() {
    aesTest();
    return 0;
}

Answer 1

使用std::string捕获加密数据时，由于加密字符串中存在''，可能会丢失一些数据。

请尝试使用std::vector<char>。

void aes::encrypt(string text, std::vector<char>& ret) {
    size_t textLength = text.size() + 1;
    ret.resize(textLength);
    gcry_cipher_encrypt(handle, ret.data(), textLength, text.c_str(), textLength);
}
string aes::decrypt(std::vector<char> const& text) {
    size_t textLength = text.size() + 1;
    // Since you are in C++ land, use new and delete
    // instead of malloc and free.
    char * decBuffer = new char[textLength];
    gcry_cipher_decrypt(handle, decBuffer, textLength, text.data(), textLength);
    string ret (decBuffer);
    delete [] decBuffer;
    return ret;
}