sm4 加解密示例

 1 int do_crypt(char *outfile)
 2         {
 3         unsigned char outbuf[1024];
 4         int outlen, tmplen;
 5         /* Bogus key and IV: we'd normally set these from
 6          * another source.
 7          */
 8         unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
 9         unsigned char iv[] = {1,2,3,4,5,6,7,8};
10         char intext[] = "Some Crypto Text";
11         EVP_CIPHER_CTX *ctx;
12         FILE *out;
13 
14         ctx = EVP_CIPHER_CTX_new();
15         EVP_EncryptInit_ex(ctx, EVP_idea_cbc(), NULL, key, iv);
16 
17         if(!EVP_EncryptUpdate(ctx, outbuf, &outlen, intext, strlen(intext)))
18                 {
19                 /* Error */
20                 return 0;
21                 }
22         /* Buffer passed to EVP_EncryptFinal() must be after data just
23          * encrypted to avoid overwriting it.
24          */
25         if(!EVP_EncryptFinal_ex(ctx, outbuf + outlen, &tmplen))
26                 {
27                 /* Error */
28                 return 0;
29                 }
30         outlen += tmplen;
31         EVP_CIPHER_CTX_free(ctx);
32         /* Need binary mode for fopen because encrypted data is
33          * binary data. Also cannot use strlen() on it because
34          * it won't be null terminated and may contain embedded
35          * nulls.
36          */
37         out = fopen(outfile, "wb");
38         fwrite(outbuf, 1, outlen, out);
39         fclose(out);
40         return 1;
41         }

 1  int do_crypt(FILE *in, FILE *out, int do_encrypt)
 2         {
 3         /* Allow enough space in output buffer for additional block */
 4         unsigned char inbuf[1024], outbuf[1024 + EVP_MAX_BLOCK_LENGTH];
 5         int inlen, outlen;
 6         EVP_CIPHER_CTX *ctx;
 7         /* Bogus key and IV: we'd normally set these from
 8          * another source.
 9          */
10         unsigned char key[] = "0123456789abcdeF";
11         unsigned char iv[] = "1234567887654321";
12 
13         /* Don't set key or IV right away; we want to check lengths */
14         ctx = EVP_CIPHER_CTX_new();
15         EVP_CipherInit_ex(&ctx, EVP_aes_128_cbc(), NULL, NULL, NULL,
16                 do_encrypt);
17         OPENSSL_assert(EVP_CIPHER_CTX_key_length(ctx) == 16);
18         OPENSSL_assert(EVP_CIPHER_CTX_iv_length(ctx) == 16);
19 
20         /* Now we can set key and IV */
21         EVP_CipherInit_ex(ctx, NULL, NULL, key, iv, do_encrypt);
22 
23         for(;;)
24                 {
25                 inlen = fread(inbuf, 1, 1024, in);
26                 if (inlen <= 0) break;
27                 if(!EVP_CipherUpdate(ctx, outbuf, &outlen, inbuf, inlen))
28                         {
29                         /* Error */
30                         EVP_CIPHER_CTX_free(ctx);
31                         return 0;
32                         }
33                 fwrite(outbuf, 1, outlen, out);
34                 }
35         if(!EVP_CipherFinal_ex(ctx, outbuf, &outlen))
36                 {
37                 /* Error */
38                 EVP_CIPHER_CTX_free(ctx);
39                 return 0;
40                 }
41         fwrite(outbuf, 1, outlen, out);
42 
43         EVP_CIPHER_CTX_free(ctx);
44         return 1;
45         }

 

 

 

 

// openssl.org/docs/man1.1.0/man3/EVP_EncryptInit_ex.html