Question

我正在尝试为PSP制作MMORPG，我将以某种形式加密通过网络发送的数据。我为此选择了AES。

我有这段代码：

int encrypt(unsigned char *plaintext, int plaintext_len, unsigned char *key, unsigned char *iv, unsigned char *ciphertext){

int len;

int ciphertext_len;

/* Create and initialise the context */
EVP_CIPHER_CTX_init(&ctx);
appendLog("CTX Init", LOG_CRYPTO);
/* Initialise the encryption operation. IMPORTANT - ensure you use a key
* and IV size appropriate for your cipher
* In this example we are using 256 bit AES (i.e. a 256 bit key). The
* IV size for *most* modes is the same as the block size. For AES this
* is 128 bits */
if(1 != EVP_EncryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, key, iv))
    printLastError("2");
appendLog("Encrypt started", LOG_CRYPTO);
/* Provide the message to be encrypted, and obtain the encrypted output.
* EVP_EncryptUpdate can be called multiple times if necessary
*/
if(1 != EVP_EncryptUpdate(&ctx, ciphertext, &len, plaintext, plaintext_len))
    printLastError("3");
ciphertext_len = len;
appendLog("Mid encrypt", LOG_CRYPTO);
/* Finalise the encryption. Further ciphertext bytes may be written at
* this stage.
*/
if(1 != EVP_EncryptFinal_ex(&ctx, ciphertext + len, &len)) printLastError("4");
ciphertext_len += len;
appendLog("Encrypt final", LOG_CRYPTO);
/* Clean up */
EVP_CIPHER_CTX_cleanup(&ctx);
appendLog("CTX Cleanup", LOG_CRYPTO);
return ciphertext_len;
}

在将“Mid encrypt”写入日志后冻结了我的PSP。我想知道这段代码是否有任何明显的错误。我正在使用openSSL v0.9.7j进行PSP。

原始的AES加密代码：

int encrypt(unsigned char *plaintext, int plaintext_len, unsigned char *key, unsigned char *iv, unsigned char *ciphertext){
EVP_CIPHER_CTX *ctx;

int len;

int ciphertext_len;

/* Create and initialise the context */
if(!(ctx = EVP_CIPHER_CTX_new())) exit(0);

/* Initialise the encryption operation. IMPORTANT - ensure you use a key
* and IV size appropriate for your cipher
* In this example we are using 256 bit AES (i.e. a 256 bit key). The
* IV size for *most* modes is the same as the block size. For AES this
* is 128 bits */
if(1 != EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv))
exit(0);

/* Provide the message to be encrypted, and obtain the encrypted output.
* EVP_EncryptUpdate can be called multiple times if necessary
*/
if(1 != EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len))
exit(0);
ciphertext_len = len;

/* Finalise the encryption. Further ciphertext bytes may be written at
* this stage.
*/
if(1 != EVP_EncryptFinal_ex(ctx, ciphertext + len, &len)) exit(0);
ciphertext_len += len;

/* Clean up */
EVP_CIPHER_CTX_free(ctx);
return ciphertext_len;
}

PSPSDK openSSL没有函数EVP_CIPHER_CTX_new（）或EVP_CIPHER_CTX_free（），我的EVP_CIPHER_CTX是全局声明的，不再在函数中声明。

我的函数调用：

char *newS;
char AESKey[32];
char IV[16];
sprintf(AESKey, "12345678901234567890123456789012");
sprintf(IV, "1234567890123456");
encrypted_length = encrypt("HelloFromPSP", strlen("HelloFromPSP"), AESKey, IV, newS);

任何人都可以帮我弄清楚为什么EVP_EncryptFinal_ex会出现问题吗？

编辑：不知何故通过回到我的旧代码（这也是冻结，奇怪）设法修复

char encrypted[4098]; //Could be smaller but is this size because it holds RSA data at some points in the code
char AESKey[32]; //Recieved from server, no sprintf filling this
char IV[16]; //Recieved from server, no sprintf filling this
encrypted_length = encrypt("HelloFromPSP", strlen("HelloFromPSP"), AESKey, IV, encrypted);

PSP上的EVP AES加密

0 个答案: