关于des加密的示例

分手后的思念是犯贱 2022-10-02 10:45 121阅读 0赞

c中常用的是`openssl`的`crypto`库中的方法：

openssl中的测试代码：[Link][]

static int test_des_cbc(void)
    { 
        unsigned char cbc_in[40];
        unsigned char cbc_out[40];
        DES_cblock iv3;
        DES_key_schedule ks;
        const size_t cbc_data_len = strlen((char *)cbc_data);
    
        if (!TEST_int_eq(DES_set_key_checked(&cbc_key, &ks), 0))
            return 0;
        memset(cbc_out, 0, sizeof(cbc_out));
        memset(cbc_in, 0, sizeof(cbc_in));
        memcpy(iv3, cbc_iv, sizeof(cbc_iv));
        DES_ncbc_encrypt(cbc_data, cbc_out, cbc_data_len + 1, &ks,
                         &iv3, DES_ENCRYPT);
        if (!TEST_mem_eq(cbc_out, 32, cbc_ok, 32))
            return 0;
    
        memcpy(iv3, cbc_iv, sizeof(cbc_iv));
        DES_ncbc_encrypt(cbc_out, cbc_in, cbc_data_len + 1, &ks,
                         &iv3, DES_DECRYPT);
        return TEST_mem_eq(cbc_in, cbc_data_len, cbc_data, cbc_data_len);
    }

常用函数说明：[LINK][]

nt DES_set_key_checked (DES_cblock *key, DES_key_schedule *ks)
    Just like DES_set_key_unchecked() except checking that the key is not weak for or have correct parity.
    Parameters:
    
    key a key to initialize the key schedule with. 
    ks a key schedule to initialize.
    Returns:
    
    0 on success, -1 on invalid parity, -2 on weak key.
     
    
    int DES_set_key_unchecked (DES_cblock *key, DES_key_schedule *ks)
    Setup a des key schedule from a key. The key is no longer needed after this transaction and can cleared.
    Does NOT check that the key is weak for or have wrong parity.
    
    Parameters:
    
    key a key to initialize the key schedule with. 
    ks a key schedule to initialize.
    Returns:
    
    0 on success
     
    
    void DES_set_odd_parity (DES_cblock *key)
    Set the parity of the key block, used to generate a des key from a random key. See DES key generation.
    Parameters:
    
    key key to fixup the parity for.

更详细一点的解释：[LINK][LINK 1]

[Link]: https://github.com/openssl/openssl/blob/1057c2c39f5df45c36c0fc4d78dc9d3b91f78bc6/test/destest.c
[LINK]: https://www.systutorials.com/docs/linux/man/3-DES_cbc_encrypt/
[LINK 1]: http://web.mit.edu/macdev/Development/MITKerberos/MITKerberosLib/DESLib/Documentation/api.html