mac check in gcm failed
时间: 2023-05-01 09:06:25 浏览: 175
“mac check in gcm failed”的意思是“在GCM中MAC检查失败”。这通常是因为GCM加密密钥不正确或消息被篡改导致的。如果您遇到此错误,请检查您的GCM加密密钥,并确认消息没有被篡改。
相关问题
openssl GCM
OpenSSL is a widely-used open-source cryptographic library that provides support for various cryptographic algorithms, including the GCM (Galois/Counter Mode) encryption mode.
GCM is an authenticated encryption mode that provides both confidentiality and integrity. It combines the Counter (CTR) mode of encryption with a universal hash function called Galois Message Authentication Code (GMAC). GCM is commonly used for secure communication protocols like TLS.
To use GCM with OpenSSL, you can utilize the EVP (Envelope) API provided by OpenSSL. Here's an example of how you can use OpenSSL to perform GCM encryption and decryption:
```c
#include <openssl/evp.h>
void encrypt_decrypt_gcm(const unsigned char* key, const unsigned char* iv, const unsigned char* aad,
const unsigned char* ciphertext, int ciphertext_len, unsigned char* tag,
unsigned char* plaintext) {
EVP_CIPHER_CTX* ctx;
int len;
int plaintext_len;
// Create and initialize the context
ctx = EVP_CIPHER_CTX_new();
EVP_EncryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, NULL, NULL);
// Set the key and IV
EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_KEY_LEN, 256, NULL);
EVP_EncryptInit_ex(ctx, NULL, NULL, key, iv);
// Set the AAD (Additional Authenticated Data)
EVP_EncryptUpdate(ctx, NULL, &len, aad, sizeof(aad));
// Perform the encryption
EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len);
// Finalize the encryption (generates the authentication tag)
EVP_EncryptFinal_ex(ctx, ciphertext + len, &len);
EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_GET_TAG, 16, tag);
// Cleanup
EVP_CIPHER_CTX_free(ctx);
}
int main() {
unsigned char key[32]; // 256-bit key
unsigned char iv[12]; // 96-bit IV
unsigned char aad[16]; // Additional Authenticated Data
unsigned char ciphertext[128];
unsigned char tag[16];
unsigned char plaintext[128];
// Initialize the key, IV, AAD, and plaintext
encrypt_decrypt_gcm(key, iv, aad, ciphertext, sizeof(ciphertext), tag, plaintext);
return 0;
}
```
In this example, you would need to replace the placeholders for the key, IV, AAD, ciphertext, and plaintext with the actual data you want to use. Additionally, make sure to include the necessary OpenSSL headers and link against the OpenSSL library when compiling.
This is just a basic example and it's important to use proper cryptographic practices and ensure the security of your implementation. It's recommended to refer to the OpenSSL documentation and consult cryptographic experts for more guidance on using GCM with OpenSSL.
aes gcm tag
AES (Advanced Encryption Standard) GCM (Galois/Counter Mode) 是一种常用的对称加密模式,结合了加密和认证功能。GCM 包括一个数据包(cipher text)和一个附加的认证标签(tag),用于验证数据在传输过程中的完整性和真实性。
- **AES GCM 加密**:使用 AES 作为基础加密算法,将明文分块并通过AES进行加密。加密过程中,生成一个密钥流并与明文进行异或操作,生成加密后的密文。
- **GCM 认证**:使用 Galois/Counter Mode 的伪随机函数(CTR,Counter Mode)生成一个与密钥关联的流,这个流被用来计算一个消息认证码(MAC)。MAC 参与加密过程,生成一个固定长度的标签,通常为16字节。
- **AES GCM 标签**:MAC 就是所谓的“标签”,它是加密数据的一个哈希值,存储在密文的末尾。接收者用相同的密钥和原始密文重新计算标签,如果两个标签匹配,说明数据在传输中没有被篡改。
- **验证**:在接收端,接收者使用相同密钥解密并重新生成标签,如果新生成的标签与接收到的标签一致,那么数据的完整性就得到了确认。
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