ase方式对bmp图像进行加密

ase方式对bmp图像进行加密

废话不多说，直接上代码

#define  _CRT_SECURE_NO_WARNINGS
#include <openssl/conf.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

void handleErrors()
{
    
    
    printf("Wrong encryption progress\n");
}

int encrypt(unsigned char *plaintext, int plaintext_len, unsigned char *key, unsigned char *iv, unsigned char *ciphertext)
{
    
    
    EVP_CIPHER_CTX *ctx;
    int len;
    int ciphertext_len;

    /* Create and initialise the context */
    if (!(ctx = EVP_CIPHER_CTX_new()))
        handleErrors();

    /* Initialise the encryption operation. IMPORTANT - ensure you use a key
     * and IV size appropriate for your cipher
     */
    if (1 != EVP_EncryptInit_ex(ctx, EVP_aes_128_cbc(), NULL, key, iv))
        handleErrors();

    /* Provide the message to be encrypted, and obtain the encrypted output.
     * EVP_EncryptUpdate can be called multiple times if necessary
     */
    if (1 != EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len))
        handleErrors();

    ciphertext_len = len;

    /* Finalise the encryption. Further ciphertext bytes may be written at
     * this stage.
     */
    if (1 != EVP_EncryptFinal_ex(ctx, ciphertext + len, &len))
        handleErrors();

    ciphertext_len += len;

    /* Clean up */
    EVP_CIPHER_CTX_free(ctx);

    return ciphertext_len;

}
int main(int argc, char **argv)
{
    
    

    const char * fileName = "D:\\work\\code\\gitlab\\image_entroy\\Debug\\pic_original.bmp";
    const char * outfileName = "D:\\work\\code\\gitlab\\image_entroy\\Debug\\pic_original_ent.bmp";
    unsigned char *pBmpBuf;//读入图像数据的指针

    //======================= STEP 0=====================================//
    /*Key initialization.
     It will be automaticalledly padded to 128 bit key
     */
    unsigned char *key = (unsigned char *)"29285542";

    //======================= STEP 1=====================================//
    /*IV initialization.
     The IV size for *most* modes is the same as the block size.
     For AES128 this is 128 bits
     */
    unsigned char *iv = (unsigned char *)"1234567890123456";
    //======================= STEP 2=====================================//
    /*read the file from given filename in binary mode*/
    printf("Start to read the .bmp file \n");

    FILE *fp;

    fp = fopen(fileName, "rb");

    if (fp == NULL) {
    
    

        printf("Open Unsuccessfully");

    }
    else printf("Open Successfully");


    const int FILE_SIZE = 184974;
    unsigned char ciphertext[FILE_SIZE];
    //======================= STEP 3=====================================//
    /*allocate memory for bitmapHeader and bitmapImage,
     then read bytes for these variables.*/
     //allocate memory for the final ciphertext
    unsigned char *header = (unsigned char*)malloc(54);
    
     /*as this is a .bmpfile, we need to read the header
      (the first 54 bytes) into bitmapHeader*/
    fread(header, 54, 1, fp); //获取图像宽、高、每像素所占位数等信息

    int bmpWidth = 460;

    int bmpHeight = 134;

    int biBitCount = 24;//定

    int lineByte = (bmpWidth * biBitCount / 8 + 3) / 4 * 4;//灰度图像有颜色表，且颜色表表项为256

    pBmpBuf = (unsigned char*)malloc(lineByte * bmpHeight);

    fread(pBmpBuf, 1, lineByte * bmpHeight, fp);

    fclose(fp);//关闭文件


      //read the bitmap image content until the end of the .bmp file



      //======================= STEP 4=====================================//
      //encrypt the bitmapImage with the given studentID key

    int ciphertextlen = encrypt(pBmpBuf, lineByte * bmpHeight, key,iv, ciphertext);

    //======================= STEP 5=====================================//
    /*merge header and bitmap to the final ciphertext
     and output it into a .bmp file*/

    FILE *p = fopen(outfileName, "w+");

    fwrite(header, 54, 1, p);

    fwrite(ciphertext, ciphertextlen, 1, p);

    free(pBmpBuf);
    free(header);

    return 1;
}

加密前输入图片为：

加密后的图片：