1*4882a593Smuzhiyun #include <stdio.h>
2*4882a593Smuzhiyun #include <stdlib.h>
3*4882a593Smuzhiyun #include <string.h>
4*4882a593Smuzhiyun #include <assert.h>
5*4882a593Smuzhiyun #include "des_core.h"
6*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)7*4882a593Smuzhiyun static void rk_crypto_ofb128_encrypt(void *ctx, const unsigned char *in, unsigned char *out,
8*4882a593Smuzhiyun int len, unsigned char *ivec, unsigned int *num,block128_f block)
9*4882a593Smuzhiyun {
10*4882a593Smuzhiyun int n, l=0;
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun n = *num;
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun while (l<len) {
15*4882a593Smuzhiyun if (n==0) {
16*4882a593Smuzhiyun (*block)(ivec, ivec, ctx);
17*4882a593Smuzhiyun }
18*4882a593Smuzhiyun out[l] = in[l] ^ ivec[n];
19*4882a593Smuzhiyun ++l;
20*4882a593Smuzhiyun n = (n+1) % DES_BLOCK_SIZE;
21*4882a593Smuzhiyun }
22*4882a593Smuzhiyun
23*4882a593Smuzhiyun *num=n;
24*4882a593Smuzhiyun }
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun /* XTS makes use of two different keys, usually generated by splitting
27*4882a593Smuzhiyun * the supplied block cipher's key in half.
28*4882a593Smuzhiyun * Because of the splitting, users wanting AES 256 and AES 128 encryption
29*4882a593Smuzhiyun * will need to choose key sizes of 512 bits and 256 bits respectively.
30*4882a593Smuzhiyun */
rk_des_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)31*4882a593Smuzhiyun int rk_des_ofb_encrypt(const unsigned char *in, unsigned char *out,
32*4882a593Smuzhiyun unsigned long length, const unsigned char *key, const int key_len,
33*4882a593Smuzhiyun unsigned char *ivec, const int enc)
34*4882a593Smuzhiyun {
35*4882a593Smuzhiyun rk_des_context ctx;
36*4882a593Smuzhiyun rk_des3_context ctx3;
37*4882a593Smuzhiyun unsigned int num = 0;
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun if(key_len != 8 && key_len != 16 && key_len != 24)
40*4882a593Smuzhiyun return -1;
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun if(length == 0)
43*4882a593Smuzhiyun return -1;
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun switch(key_len){
46*4882a593Smuzhiyun case 8:
47*4882a593Smuzhiyun rk_des_setkey_enc(&ctx, key);
48*4882a593Smuzhiyun rk_crypto_ofb128_encrypt((void*)&ctx, in, out, length, ivec, &num, rk_des_crypt_ecb);
49*4882a593Smuzhiyun break;
50*4882a593Smuzhiyun case 16:
51*4882a593Smuzhiyun rk_des3_set2key_enc(&ctx3, key);
52*4882a593Smuzhiyun rk_crypto_ofb128_encrypt((void*)&ctx3, in, out, length, ivec, &num, rk_des3_crypt_ecb);
53*4882a593Smuzhiyun break;
54*4882a593Smuzhiyun case 24:
55*4882a593Smuzhiyun rk_des3_set3key_enc(&ctx3, key);
56*4882a593Smuzhiyun rk_crypto_ofb128_encrypt((void*)&ctx3, in, out, length, ivec, &num, rk_des3_crypt_ecb);
57*4882a593Smuzhiyun break;
58*4882a593Smuzhiyun default:
59*4882a593Smuzhiyun return -1;
60*4882a593Smuzhiyun }
61*4882a593Smuzhiyun
62*4882a593Smuzhiyun return 0;
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun
65