main.java

AES,DES,RSA,SHA1四个加密解密算法。

/*
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 */

package RSA;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.math.BigInteger;


/**
 *
 * @author Fredrik
 */
public class Main {

    /**
     * @param args the command line arguments
     */
     public static void main(String[] args)throws IOException {
    	 RSA myRSA=new RSA(256);
         
         //performs three encryptions and decryptions
         //the values are taken from http://www.skepticfiles.org/faq/testdes.htm
         String filename = "D:\\My Documents\\test.JPG";
         File sourceFile = new File(filename);
         String enfile = filename + ".encrypt";
         File encryptfile = new File(enfile);
         int fileSize = (int) (sourceFile.length());
	        int block ;
	        if(fileSize%31==0)
	        	block= ((int) (fileSize / 31));
	        else
	        	block= ((int) (fileSize / 31))+1;
	        fileSize = 32 * block ;
	        byte[] buff = new byte[fileSize];
			byte[] temp = new byte[32];
			//System.out.println(block);
 		FileOutputStream out = null;
 		FileInputStream in = new FileInputStream(sourceFile);
 		in.read(buff);
 		in.close();
 		//加密开始
 		long begin = System.currentTimeMillis();//计时开始
 		for(int j = 0 ; j<block ; j++){
        	for(int k=0 ; k<31 ; k++)	{
        		temp[k] = buff[j*31+k];		        		
        	}
        	BigInteger bigtemp  = new BigInteger(temp);
     		//System.out.printf("%02x\n",temp);
     		BigInteger ciphertext=myRSA.encrypt(bigtemp);
     		temp = ciphertext.toByteArray();
        	for(int k=0 ; k<31 ; k++){
        		buff[j*31+k] = temp[k];
        		//System.out.println(k);
        	}
        }
 		
 		out = new FileOutputStream(encryptfile);
 		out.write(buff);
 		out.close();
 		long current = System.currentTimeMillis();
 		System.out.println((current - begin) + " ms");//计时结束
 		System.out.println("Encrypt Success!");
 		//加密结束
 		
 		
 		in = new FileInputStream(encryptfile);
 		in.read(buff); 			
 		in.close(); 		
 		String defile = filename + ".decrypt";
         File decryptfile = new File(defile);
 		//解密开始
        begin = System.currentTimeMillis();//计时开始
        for(int j = 0 ; j<block ; j++){
        	for(int k=0 ; k<31 ; k++)	{
        		temp[k] = buff[j*31+k];		        		
        	}
        	BigInteger bigtemp  = new BigInteger(temp);
     		//System.out.printf("%02x\n",temp);
     		BigInteger ciphertext=myRSA.decrypt(bigtemp);
     		temp = ciphertext.toByteArray();
        	for(int k=0 ; k<31 ; k++){
        		buff[j*31+k] = temp[k];
        	}
        }
        /*bigtemp  = new BigInteger(buff);
        ciphertext=myRSA.decrypt(bigtemp);
 		buff = ciphertext.toByteArray();*/
 		out = new FileOutputStream(decryptfile);
 		out.write(buff);
 		out.close();
 		current = System.currentTimeMillis();
 		System.out.println((current - begin) + " ms");//计时结束
 		System.out.println("Decrypt Success!");
 	
      /* 
       BigInteger[] plaintext={BigInteger.valueOf(10),BigInteger.valueOf(20),BigInteger.valueOf(30)};
       for(int i=0;i<plaintext.length;i++)
           System.out.printf("%02x ", plaintext[i]);
       System.out.println();
       BigInteger[] ciphertext=myRSA.encrypt(plaintext);
       for(int i=0;i<ciphertext.length;i++)
           System.out.printf("%02x ", ciphertext[i]);
       System.out.println();
       BigInteger[] decrypted=myRSA.decrypt(ciphertext);
       for(int i=0;i<decrypted.length;i++)
           System.out.printf("%02x ", decrypted[i]);
       System.out.println();*/
    }

}