evp_encrypt不能在c中的for循环中工作

我是新来的，所以请原谅我做错了什么。

我尝试使用加密字符串创建一个数组，我正在使用EVP API进行加密。 这工作正常，但是我尝试在foor循环中使用加密function，控制台什么也没给我。

这是我的加密function：

char *encrypt(char *key, char *iv, char * source){ //char *target; int in_len, out_len; EVP_CIPHER_CTX ctx; in_len=strlen((const char *)source); unsigned char *target = (unsigned char *) malloc(in_len); //printf("This is the text before ciphering: %s\n",source); //printf("The length of the string is: %d\n",in_len); //starting the encryption process EVP_CIPHER_CTX_init(&ctx); EVP_EncryptInit_ex(&ctx,EVP_aes_128_cbc(),NULL,(unsigned char*) key,(unsigned char*)iv); EVP_EncryptUpdate(&ctx,target,&out_len,(unsigned char*)source,in_len); EVP_EncryptFinal_ex(&ctx,target,&out_len); target[out_len] = '\0'; //EVP_CIPHER_CTX_cleanup(&ctx); return ((char *)target); } 

并在主循环中：

 int main(){ char source[17]="Shahababamamaaaa"; char key[17]="ahardtobreakkey1"; char iv[17] = "veryinterestingv"; int rows = 1280; int cols = (3*800)/16; char *encrypted=encrypt(key, iv, source); printf("encrypted: %s\n", encrypted); char *encrypted2; encrypted2=encrypt(key, iv, encrypted); printf("encrypted2: %s\n", encrypted2); char *mx[rows]; char *in, *temp; in = (char *) malloc ( cols * sizeof(char) ); temp =(char *) malloc ( strlen(encrypted) ); int i, j; for (i=0; i<5; i++){ strcpy(in,encrypted); for(j=0;j<3;j++){ printf("in: %s\n", in); strcpy(temp, encrypted2); printf("temp: %s\n", temp); memset(encrypted2,0x00, strlen(encrypted)); encrypted2=encrypt(key, iv,temp); printf("encrypted2 nach j=%d : %s\n",j, encrypted2); mx[i]=in; } } printf("Stele 0 Inhalt %s\n",mx[0]); printf("Laenge von 1 %d\n", strlen(mx[0])); //system ("PAUSE"); free(in); return 0; } 

我错过了什么？ 再次使用encrypt2是不可能的吗？ 非常感谢你。

Answer 1

正如您所说，主要问题在于您的encrypt（）函数，以及您如何调用它。 您正在使用malloc（）在函数内部分配内存，并且永远不会释放它，这是一个内存泄漏（无论如何，malloc在c ++中都是禁忌）。 您也没有为ctx运行清理function。 而你的encrypt_final正在覆盖输出缓冲区的第一部分。 所以，这是一个清理的encrypt（）和一个匹配的decrypt（）：

 int encrypt(unsigned char *key, unsigned char *iv, unsigned char * source, unsigned char* target, int in_len) // Need an in length. Not all input is going to be // zero-terminated, for example if we're reading from a file { int out_len; // Return the output length. Because it also won't be null // terminated, and may contain null characters inline int final_out_len; // So that we don't overwrite out_len with the final call EVP_CIPHER_CTX ctx; EVP_CIPHER_CTX_init(&ctx); EVP_EncryptInit_ex(&ctx,EVP_aes_128_cbc(),NULL,key,iv); EVP_EncryptUpdate(&ctx,target,&out_len,source,in_len); EVP_EncryptFinal_ex(&ctx,target+out_len,&final_out_len); EVP_CIPHER_CTX_cleanup(&ctx); return out_len+final_out_len; // need to sum these together, because both // encrypt calls wrote data } 

并解密：

 int decrypt(unsigned char *key, unsigned char *iv, unsigned char * source, unsigned char* target, int in_len) { int out_len=0,final_out_len=0; EVP_CIPHER_CTX ctx; EVP_CIPHER_CTX_init(&ctx); EVP_DecryptInit_ex(&ctx,EVP_aes_128_cbc(),NULL,key,iv); EVP_DecryptUpdate(&ctx,target,&out_len,source,in_len); EVP_DecryptFinal_ex(&ctx,target+out_len,&final_out_len); EVP_CIPHER_CTX_cleanup(&ctx); //Just to be nice, we'll add a zero at the end of the decrypted string target[out_len+final_out_len] = 0; return out_len+final_out_len; } 

把它们拉在一起（循环，以certificate你的概念）：

 int _tmain(int argc, _TCHAR* argv[]) { unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15}; unsigned char ivec[] = {1,2,3,4,5,6,7,8}; char *raw_buffer = "This is a test string"; int raw_count = strlen(raw_buffer); for (int i=0; i<5; i++){ unsigned char *decrypted_buffer = new unsigned char[raw_count+64]; unsigned char *encrypted_buffer = new unsigned char[raw_count+64]; int final_len = encrypt(key,ivec,(unsigned char*)raw_buffer,(unsigned char*)encrypted_buffer,raw_count); int dec_len = decrypt(key,ivec,(unsigned char*)encrypted_buffer,(unsigned char*)decrypted_buffer,final_len); printf("raw_count: %i\nfinal_len: %i\ndec_len: %i\n",raw_count,final_len,dec_len); printf("Original str: \n%s\n",raw_buffer); printf("Encrypted: \n%s\n", encrypted_buffer); printf("Decrypted:\n%s\n\n\n", decrypted_buffer); delete[] decrypted_buffer; delete[] encrypted_buffer; } char c; c=getchar(); return 0; }