49 lines
1.1 KiB
C
49 lines
1.1 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "sm4_core.h"
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static void rk_crypto_ofb128_encrypt(void *ctx, const unsigned char *in, unsigned char *out,
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int len, unsigned char *ivec, unsigned int *num,block128_f block)
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{
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int n, l=0;
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n = *num;
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while (l<len) {
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if (n==0) {
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(*block)(ivec, ivec, ctx);
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}
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out[l] = in[l] ^ ivec[n];
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++l;
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n = (n+1) % SM4_BLOCK_SIZE;
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}
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*num=n;
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}
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/* XTS makes use of two different keys, usually generated by splitting
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* the supplied block cipher's key in half.
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* Because of the splitting, users wanting AES 256 and AES 128 encryption
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* will need to choose key sizes of 512 bits and 256 bits respectively.
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*/
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int rk_sm4_ofb_encrypt(const unsigned char *in, unsigned char *out,
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unsigned long length, const unsigned char *key, const int key_len,
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unsigned char *ivec, const int enc)
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{
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sm4_context ctx;
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unsigned int num = 0;
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if(key_len != 16)
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return -1;
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if(length == 0)
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return -1;
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rk_sm4_setkey_enc(&ctx, key);
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rk_crypto_ofb128_encrypt((void*)&ctx, in, out, length, ivec, &num, rk_rk_sm4_crypt_ecb);
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return 0;
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}
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