JDK自带方法实现RSA数字签名

JDK只支持MD2withRSA, MD5withRSA, SHA1withRSA

其他的如SHA512withRSA需要第三方包支持，如BC(bouncy castle)

JDK的密钥长度默认仍是1024

  1 package jdbc.pro.lin;
  2
  3 import java.security.InvalidKeyException;
  4 import java.security.NoSuchAlgorithmException;
  5 import java.security.PrivateKey;
  6 import java.security.PublicKey;
  7 import java.security.Signature;
  8 import java.security.SignatureException;
  9 import java.util.Map;
 10
 11 import jdbc.pro.lin.MyRSA;
 12
 13 /**
 14  * RSA数字签名，借用MyRSA中的算法，不再重复
 15  * 数字签名遵循“私钥签名，公钥验签”原则，因为私钥是个人身份认证
 16  * @author Kinsley
 17  *
 18  */
 19 public class MySignature {
 20
 21     /** 数字签名算法。JDK只提供了MD2withRSA, MD5withRSA, SHA1withRSA，其他的算法需要第三方包才能支持 */
 22     public static final String SIGNATURE_ALGORITHM = "SHA1withRSA";
 23
 24     public static final String PLAIN_TEXT = "MANUTD is the greatest club in the world";
 25     public static void main(String[] args)
 26     {
 27         //建立两套公私钥对
 28         Map<String, byte[]> keyMap1 = MyRSA.generateKeyBytes();
 29         PublicKey publicKey1 = MyRSA.restorePublicKey(keyMap1.get(MyRSA.PUBLIC_KEY));
 30         PrivateKey privateKey1 = MyRSA.restorePrivateKey(keyMap1.get(MyRSA.PRIVATE_KEY));
 31
 32         Map<String, byte[]> keyMap2 = MyRSA.generateKeyBytes();
 33         PublicKey publicKey2 =MyRSA.restorePublicKey(keyMap2.get(MyRSA.PUBLIC_KEY));
 34         PrivateKey privateKey2 =MyRSA.restorePrivateKey(keyMap2.get(MyRSA.PRIVATE_KEY));
 35
 36         /** 假设现在A签名后向B发送消息
 37          * A用B的公钥进行加密
 38          * 用自己A的私钥进行签名
 39          */
 40         byte[] encodedText = MyRSA.RSAEncode(publicKey2, PLAIN_TEXT.getBytes());
 41         byte[] signature = sign(privateKey1, PLAIN_TEXT.getBytes());
 42
 43         /**
 44          * 现在B收到了A的消息，进行两步操作
 45          * 用B的私钥解密得到明文
 46          * 将明文和A的公钥进行验签操作
 47          */
 48
 49         byte[] decodedText = MyRSA.RSADecode(privateKey2, encodedText).getBytes();
 50         System.out.println("Decoded Text: " + new String(decodedText));
 51
 52         System.out.println("Signature is " + verify(publicKey1, signature, decodedText));
 53     }
 54
 55     /**
 56      * 签名，三步走
 57      * 1. 实例化，传入算法
 58      * 2. 初始化，传入私钥
 59      * 3. 签名
 60      * @param key
 61      * @param plainText
 62      * @return
 63      */
 64     public static byte[] sign(PrivateKey privateKey, byte[] plainText)
 65     {
 66         try {
 67             //实例化
 68             Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
 69
 70             //初始化，传入私钥
 71             signature.initSign(privateKey);
 72
 73             //更新
 74             signature.update(plainText);
 75
 76             //签名
 77             return signature.sign();
 78
 79         } catch (NoSuchAlgorithmException | InvalidKeyException | SignatureException e) {
 80             // TODO Auto-generated catch block
 81             e.printStackTrace();
 82         }
 83
 84         return null;
 85     }
 86
 87     /**
 88      * 验签，三步走
 89      * 1. 实例化，传入算法
 90      * 2. 初始化，传入公钥
 91      * 3. 验签
 92      * @param publicKey
 93      * @param signatureVerify
 94      * @param plainText
 95      * @return
 96      */
 97     public static boolean verify(PublicKey publicKey, byte[] signatureVerify, byte[] plainText )
 98     {
 99         try {
100             //实例化
101             Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
102
103             //初始化
104             signature.initVerify(publicKey);
105
106             //更新
107             signature.update(plainText);
108
109             //验签
110             return signature.verify(signatureVerify);
111         } catch (NoSuchAlgorithmException | InvalidKeyException | SignatureException e) {
112             // TODO Auto-generated catch block
113             e.printStackTrace();
114         }
115
116         return false;
117     }
118 }