Java 实现DSA数字签名

DSA数字签名Java实现

import java.security.*;
import java.security.interfaces.DSAPrivateKey;
import java.security.interfaces.DSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
 

public class DSAUtils {
 	private DSAPublicKey dsaPublicKey;//公钥
 	private DSAPrivateKey dsaPrivateKey;//私钥
 	private byte[] res;//签名后产生的字节数组
 	
 	//初始化
 	public DSAUtils()throws Exception{
 		KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("DSA");
        keyPairGenerator.initialize(512);
        KeyPair keyPair = keyPairGenerator.generateKeyPair();
        this.dsaPublicKey = (DSAPublicKey) keyPair.getPublic();
        this.dsaPrivateKey = (DSAPrivateKey) keyPair.getPrivate();
 	}
 	
 	public  DSAPublicKey getPublicKey(KeyPair keyPair){
 		return (DSAPublicKey) keyPair.getPublic();
 	}
 	
 	public  DSAPrivateKey getPrivateKey(KeyPair keyPair){
 		return (DSAPrivateKey) keyPair.getPrivate();
 	}
 	
 	
 	//执行签名
 	public  void sign(String src)throws Exception{
 		
        PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(this.dsaPrivateKey.getEncoded());
        KeyFactory keyFactory = KeyFactory.getInstance("DSA");
        PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
        Signature signature = Signature.getInstance("SHA1withDSA");
        signature.initSign(privateKey);
        signature.update(src.getBytes());
        this.res = signature.sign();
        System.out.println("签名：" + bytesToHexString(res));
 	}
 	//验证签名
 	public  boolean verify(String src) throws Exception
 	{
 		
        X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(this.dsaPublicKey.getEncoded());
        KeyFactory keyFactory = KeyFactory.getInstance("DSA");
        PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
        Signature signature = Signature.getInstance("SHA1withDSA");
        signature.initVerify(publicKey);
        signature.update(src.getBytes());
        boolean bool = signature.verify(this.res);
        System.out.println("验证：" + bool);
        return bool;
 	}
   
    //byte转16位进制
    public static String bytesToHexString(byte[] src){   
    StringBuilder stringBuilder = new StringBuilder("");   
    if (src == null || src.length <= 0) {   
        return null;   
    }   
    for (int i = 0; i < src.length; i++) {   
        int v = src[i] & 0xFF;   
        String hv = Integer.toHexString(v);   
        if (hv.length() < 2) {   
            stringBuilder.append(0);   
        }   
        stringBuilder.append(hv);   
    }   
    return stringBuilder.toString();   
} 
	//测试
	public static void main(String[] args) throws Exception {
        DSAUtils util=new DSAUtils();
        util.sign("bbb");
        util.verify("bbb");
    }
}