常用数字签名算法RSA与DSA的Java程序内实现示例

package com.stone.security; 
 
import java.security.KeyPair; 
import java.security.KeyPairGenerator; 
import java.security.PrivateKey; 
import java.security.PublicKey; 
import java.util.Arrays; 
 
import javax.crypto.Cipher; 
 
/** 
 * RSA算法 公钥加密 非对称加密 
 */ 
public class RSA { 
 public static final String KEY_ALGORITHM = "RSA"; 
 public static final String CIPHER_ALGORITHM_ECB1 = "RSA/ECB/PKCS1Padding"; 
 public static final String CIPHER_ALGORITHM_ECB2 = "RSA/ECB/OAEPWithSHA-1AndMGF1Padding"; //不能用 
 public static final String CIPHER_ALGORITHM_ECB3 = "OAEPWithSHA-256AndMGF1Padding"; //不能用 
 
 static PublicKey publicKey; 
 static PrivateKey privateKey; 
 static Cipher cipher; 
 static KeyPair keyPair; 
 
 public static void main(String[] args) throws Exception { 
 method1("斯柯达U*(Sfsad7f()*^%%$"); 
 method2("斯柯达U*(Sfsad7f()*^%%$"); 
 method3("斯柯达U*(Sfsad7f()*^%%$"); 
  
 } 
 
 /** 
 * 公钥加密，私钥解密 使用默认CIPHER_ALGORITHM_ECB1 
 * @param str 
 * @throws Exception 
 */ 
 static void method1(String str) throws Exception { 
 KeyPairGenerator keyGenerator = KeyPairGenerator.getInstance(KEY_ALGORITHM); 
 KeyPair keyPair = keyGenerator.generateKeyPair(); 
 publicKey = keyPair.getPublic(); 
 privateKey = keyPair.getPrivate(); 
 cipher = Cipher.getInstance(KEY_ALGORITHM); 
 cipher.init(Cipher.ENCRYPT_MODE, publicKey); //公钥加密 
 byte[] encrypt = cipher.doFinal(str.getBytes()); 
 System.out.println("公钥加密后1：" + Arrays.toString(encrypt)); 
  
 cipher.init(Cipher.DECRYPT_MODE, privateKey);//私钥解密 
 byte[] decrypt = cipher.doFinal(encrypt); 
 System.out.println("私钥解密后1：" + new String(decrypt)); 
 } 
 
 /** 
 * 私钥加密，公钥解密 使用默认CIPHER_ALGORITHM_ECB1 
 * @param str 
 * @throws Exception 
 */ 
 static void method2(String str) throws Exception { 
 KeyPairGenerator keyGenerator = KeyPairGenerator.getInstance(KEY_ALGORITHM); 
 KeyPair keyPair = keyGenerator.generateKeyPair(); 
 publicKey = keyPair.getPublic(); 
 privateKey = keyPair.getPrivate(); 
 cipher = Cipher.getInstance(KEY_ALGORITHM); 
 cipher.init(Cipher.ENCRYPT_MODE, privateKey); //私钥加密 
 byte[] encrypt = cipher.doFinal(str.getBytes()); 
 System.out.println("私钥加密后2：" + Arrays.toString(encrypt)); 
  
 cipher.init(Cipher.DECRYPT_MODE, publicKey);//公钥解密 
 byte[] decrypt = cipher.doFinal(encrypt); 
 System.out.println("公钥解密后2：" + new String(decrypt)); 
 } 
 
 /** 
 * 私钥加密，公钥解密 使用CIPHER_ALGORITHM_ECB1 = RSA/ECB/PKCS1Padding 
 * @param str 
 * @throws Exception 
 */ 
 static void method3(String str) throws Exception { 
 KeyPairGenerator keyGenerator = KeyPairGenerator.getInstance(KEY_ALGORITHM); 
 KeyPair keyPair = keyGenerator.generateKeyPair(); 
 publicKey = keyPair.getPublic(); 
 privateKey = keyPair.getPrivate(); 
 cipher = Cipher.getInstance(CIPHER_ALGORITHM_ECB1); 
 cipher.init(Cipher.ENCRYPT_MODE, privateKey); //私钥加密 
 byte[] encrypt = cipher.doFinal(str.getBytes()); 
 System.out.println("私钥加密后3：" + Arrays.toString(encrypt)); 
  
 cipher.init(Cipher.DECRYPT_MODE, publicKey);//公钥解密 
 byte[] decrypt = cipher.doFinal(encrypt); 
 System.out.println("公钥解密后3：" + new String(decrypt)); 
 } 
} 

package com.stone.security; 
 
import java.security.Key; 
import java.security.KeyFactory; 
import java.security.KeyPair; 
import java.security.KeyPairGenerator; 
import java.security.PrivateKey; 
import java.security.PublicKey; 
import java.security.SecureRandom; 
import java.security.Signature; 
import java.security.spec.PKCS8EncodedKeySpec; 
import java.security.spec.X509EncodedKeySpec; 
import java.util.HashMap; 
import java.util.Map; 
 
import sun.misc.BASE64Decoder; 
import sun.misc.BASE64Encoder; 
 
/** 
 * DSA-Digital Signature Algorithm 是Schnorr和ElGamal签名算法的变种，被美国NIST作为DSS(DigitalSignature Standard)。 
 * 简单的说，这是一种更高级的验证方式，用作数字签名。不单单只有公钥、私钥，还有数字签名。私钥加密生成数字签名，公钥验证数据及签名。 
 * 如果数据和签名不匹配则认为验证失败！即 传输中的数据 可以不再加密，接收方获得数据后，拿到公钥与签名 验证数据是否有效 
 */ 
public class DSA { 
 /**
 *不仅可以使用DSA算法，同样也可以使用RSA算法做数字签名
 */ 
 public static final String KEY_ALGORITHM = "RSA"; 
 public static final String SIGNATURE_ALGORITHM = "MD5withRSA";*/ 
 
 public static final String KEY_ALGORITHM = "DSA"; 
 public static final String SIGNATURE_ALGORITHM = "DSA"; 
 
 public static final String DEFAULT_SEED = "$%^*%^()(HJG8awfjas7"; //默认种子 
 public static final String PUBLIC_KEY = "DSAPublicKey"; 
 public static final String PRIVATE_KEY = "DSAPrivateKey"; 
 
 public static void main(String[] args) throws Exception { 
 String str = "!@#$!#^$#&ZXVDF呆军工路爱着你*()_+"; 
 byte[] data = str.getBytes(); 
  
 Map<String, Object> keyMap = initKey();// 构建密钥 
 PublicKey publicKey = (PublicKey) keyMap.get(PUBLIC_KEY); 
 PrivateKey privateKey = (PrivateKey) keyMap.get(PRIVATE_KEY); 
 System.out.println("私钥format：" + privateKey.getFormat()); 
 System.out.println("公钥format：" + publicKey.getFormat()); 
  
  
 // 产生签名 
 String sign = sign(data, getPrivateKey(keyMap)); 
  
 // 验证签名 
 boolean verify1 = verify("aaa".getBytes(), getPublicKey(keyMap), sign); 
 System.err.println("经验证 数据和签名匹配:" + verify1); 
  
 boolean verify = verify(data, getPublicKey(keyMap), sign); 
 System.err.println("经验证 数据和签名匹配:" + verify); 
 } 
 
 /** 
 * 生成密钥 
 * 
 * @param seed 种子 
 * @return 密钥对象 
 * @throws Exception 
 */ 
 public static Map<String, Object> initKey(String seed) throws Exception { 
 System.out.println("生成密钥"); 
  
 KeyPairGenerator keygen = KeyPairGenerator.getInstance(KEY_ALGORITHM); 
 SecureRandom secureRandom = new SecureRandom(); 
 secureRandom.setSeed(seed.getBytes()); 
 //Modulus size must range from 512 to 1024 and be a multiple of 64 
 keygen.initialize(640, secureRandom); 
  
 KeyPair keys = keygen.genKeyPair(); 
 PrivateKey privateKey = keys.getPrivate(); 
 PublicKey publicKey = keys.getPublic(); 
  
 Map<String, Object> map = new HashMap<String, Object>(2); 
 map.put(PUBLIC_KEY, publicKey); 
 map.put(PRIVATE_KEY, privateKey); 
 return map; 
 } 
 
 /** 
 * 生成默认密钥 
 * 
 * @return 密钥对象 
 * @throws Exception 
 */ 
 public static Map<String, Object> initKey() throws Exception { 
 return initKey(DEFAULT_SEED); 
 } 
 
 /** 
 * 取得私钥 
 * 
 * @param keyMap 
 * @return 
 * @throws Exception 
 */ 
 public static String getPrivateKey(Map<String, Object> keyMap) throws Exception { 
 Key key = (Key) keyMap.get(PRIVATE_KEY); 
 return encryptBASE64(key.getEncoded()); //base64加密私钥 
 } 
 
 /** 
 * 取得公钥 
 * 
 * @param keyMap 
 * @return 
 * @throws Exception 
 */ 
 public static String getPublicKey(Map<String, Object> keyMap) throws Exception { 
 Key key = (Key) keyMap.get(PUBLIC_KEY); 
 return encryptBASE64(key.getEncoded()); //base64加密公钥 
 } 
 
 /** 
 * 用私钥对信息进行数字签名 
 * @param data 加密数据 
 * @param privateKey 私钥-base64加密的 
 * @return 
 * @throws Exception 
 */ 
 public static String sign(byte[] data, String privateKey) throws Exception { 
 System.out.println("用私钥对信息进行数字签名"); 
  
 byte[] keyBytes = decryptBASE64(privateKey); 
 PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes); 
 KeyFactory factory = KeyFactory.getInstance(KEY_ALGORITHM); 
 PrivateKey priKey = factory.generatePrivate(keySpec);//生成 私钥 
  
 //用私钥对信息进行数字签名 
 Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM); 
 signature.initSign(priKey); 
 signature.update(data); 
 return encryptBASE64(signature.sign()); 
 } 
 
 /** 
 * BASE64Encoder 加密 
 * @param data 要加密的数据 
 * @return 加密后的字符串 
 */ 
 private static String encryptBASE64(byte[] data) { 
 BASE64Encoder encoder = new BASE64Encoder(); 
 String encode = encoder.encode(data); 
 return encode; 
 } 
 
 /** 
 * BASE64Decoder 解密 
 * @param data 要解密的字符串 
 * @return 解密后的byte[] 
 * @throws Exception 
 */ 
 private static byte[] decryptBASE64(String data) throws Exception { 
 BASE64Decoder decoder = new BASE64Decoder(); 
 byte[] buffer = decoder.decodeBuffer(data); 
 return buffer; 
 } 
 
 /** 
 * 校验数字签名 
 * @param data 加密数据 
 * @param publicKey 
 * @param sign 数字签名 
 * @return 
 * @throws Exception 
 */ 
 public static boolean verify(byte[] data, String publicKey, String sign) throws Exception { 
 byte[] keyBytes = decryptBASE64(publicKey); 
 X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes); 
 KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); 
 PublicKey pubKey = keyFactory.generatePublic(keySpec); 
  
 Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM); 
 signature.initVerify(pubKey); 
 signature.update(data); 
  
 return signature.verify(decryptBASE64(sign)); //验证签名 
 } 
 
}