fhash.java

实现PKI/CA的数字签名部分

package signature;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.security.DigestInputStream;
import java.security.MessageDigest;


public class Fhash {
	public static void fhash(String filename,String outfilename){
		try{   
			MessageDigest md = MessageDigest.getInstance("sha-256"); 
			FileInputStream fin = new FileInputStream(filename); 
			DigestInputStream din = new DigestInputStream(fin,md);
			din.read();
			byte[] re = md.digest();	
			try{
				FileOutputStream out=new FileOutputStream(outfilename);
				out.write(re);
				out.close();
			}catch(IOException e){
				e.printStackTrace();
			}  
		}catch(Exception e){     
			e.printStackTrace();              
		}  
	}

}