SM4

1. 使用OpenSSL的命令對你的8位學號(數字)進行加密解密

openssl enc -sm4-cbc -in 20211201.txt -out ciphertext.bin -K 20211201abcdeffedcba9876543210 -iv 2021120189abcdeffedcba9876543210

2. 使用OpenSSL程式設計對"你的8位學號（數字）"進行加密解密

#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/ec.h>
int main(int argc, char *argv[])
{
    unsigned char sm4_en[512],sm4_de[512];
    int sm4enStrLen,sm4deStrLen;
    unsigned char source[7]={0x20,0x21,0x12,0x01,0x45,0x46,0x43};
    unsigned char keyStr[16]={0x15,0x67,0x28,0xe1,0x5f,0x9a,0xfc,0x01,0xd4,0xb6,0x1b,0x4e,0x44,0x5d,0xbb,0x26};
    sm4enStrLen=my_sm4encrpt(keyStr,source,7,sm4_en);
    printf("sm4enStrLen:%d\n",sm4enStrLen);
    for(int i=0;i<sm4enStrLen;++i)
    {
        printf("0x%x",sm4_en[i]);
    }
    printf("\n");
    sm4deStrLen=dencryptStr(keyStr,sm4_en,sm4enStrLen,sm4_de);
    printf("sm4deStrLen:%d\n",sm4deStrLen);
    for(int i=0;i<7;++i)
    {
        printf("0x%x",sm4_de[i]);
    }
    printf("\n");
}
int my_sm4encrpt(unsigned char * keyStr,unsigned char * surbuf,int surlen,unsigned char * enbuf)
{
    unsigned char *out_buf = enbuf;
    int out_len;
    int out_padding_len;
    int i;
    unsigned char *iv;
    EVP_CIPHER_CTX *ctx;
    ctx = EVP_CIPHER_CTX_new();
    EVP_EncryptInit(ctx, EVP_sm4_ecb(), keyStr, iv);
    if( 0 == surlen % 16 )
    {
        EVP_CIPHER_CTX_set_padding( ctx, 0 );
    }
    out_len = 0;
    EVP_EncryptUpdate(ctx, out_buf, &out_len, surbuf, surlen);
    out_padding_len = 0;
    EVP_EncryptFinal(ctx, out_buf + out_len, &out_padding_len);
 
    EVP_CIPHER_CTX_free(ctx);
    return out_len + out_padding_len;
}
 
 
int dencryptStr(unsigned char * sm4PriKey, unsigned char *cEnStr, int cEnstrlen, unsigned char *deStr)
{
    unsigned char *iv;
    EVP_CIPHER_CTX *ctx;
    int len;
    int temlen;
    int deStrLen;
    if (!(ctx = EVP_CIPHER_CTX_new())) {
       printf("EVP_CIPHER_CTX_new failed");
    }
    if (1 != EVP_DecryptInit(ctx, EVP_sm4_ecb(), sm4PriKey, iv)) {
        printf("EVP_DecryptInit_ex failed");
    }
 
 
    if (1 != EVP_DecryptUpdate(ctx, deStr, &len, cEnStr, cEnstrlen)) {
        printf("EVP_DecryptUpdate failed");
    }
    if( 0 == len % 16 )
    {
        EVP_CIPHER_CTX_set_padding( ctx, 0 );
        len += 16;
 
    }
    if( !EVP_DecryptFinal( ctx, deStr + len, &temlen ) )
    {
        printf("EVP_DecryptFinal failed");
        return EXIT_FAILURE;
    }
    deStrLen=len+temlen;
    printf("解密資料：%d\n",deStrLen);
    for (int i = 0;i < deStrLen;i++) {
        printf("0x%02x ",*(deStr + i));
    }
    printf("\n");
    EVP_CIPHER_CTX_free(ctx);
    return deStrLen;
}