1*4882a593Smuzhiyun #include <stdio.h>
2*4882a593Smuzhiyun #include <stdlib.h>
3*4882a593Smuzhiyun #include <string.h>
4*4882a593Smuzhiyun #include "sm4_core.h"
5*4882a593Smuzhiyun
rk_crypto_ofb128_encrypt(void * ctx,const unsigned char * in,unsigned char * out,int len,unsigned char * ivec,unsigned int * num,block128_f block)6*4882a593Smuzhiyun static void rk_crypto_ofb128_encrypt(void *ctx, const unsigned char *in, unsigned char *out,
7*4882a593Smuzhiyun int len, unsigned char *ivec, unsigned int *num,block128_f block)
8*4882a593Smuzhiyun {
9*4882a593Smuzhiyun int n, l=0;
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun n = *num;
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun while (l<len) {
14*4882a593Smuzhiyun if (n==0) {
15*4882a593Smuzhiyun (*block)(ivec, ivec, ctx);
16*4882a593Smuzhiyun }
17*4882a593Smuzhiyun out[l] = in[l] ^ ivec[n];
18*4882a593Smuzhiyun ++l;
19*4882a593Smuzhiyun n = (n+1) % SM4_BLOCK_SIZE;
20*4882a593Smuzhiyun }
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun *num=n;
23*4882a593Smuzhiyun }
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun /* XTS makes use of two different keys, usually generated by splitting
26*4882a593Smuzhiyun * the supplied block cipher's key in half.
27*4882a593Smuzhiyun * Because of the splitting, users wanting AES 256 and AES 128 encryption
28*4882a593Smuzhiyun * will need to choose key sizes of 512 bits and 256 bits respectively.
29*4882a593Smuzhiyun */
rk_sm4_ofb_encrypt(const unsigned char * in,unsigned char * out,unsigned long length,const unsigned char * key,const int key_len,unsigned char * ivec,const int enc)30*4882a593Smuzhiyun int rk_sm4_ofb_encrypt(const unsigned char *in, unsigned char *out,
31*4882a593Smuzhiyun unsigned long length, const unsigned char *key, const int key_len,
32*4882a593Smuzhiyun unsigned char *ivec, const int enc)
33*4882a593Smuzhiyun {
34*4882a593Smuzhiyun sm4_context ctx;
35*4882a593Smuzhiyun unsigned int num = 0;
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun if(key_len != 16)
38*4882a593Smuzhiyun return -1;
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun if(length == 0)
41*4882a593Smuzhiyun return -1;
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun rk_sm4_setkey_enc(&ctx, key);
44*4882a593Smuzhiyun rk_crypto_ofb128_encrypt((void*)&ctx, in, out, length, ivec, &num, rk_rk_sm4_crypt_ecb);
45*4882a593Smuzhiyun return 0;
46*4882a593Smuzhiyun }
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun
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