jJAVA版的RSA公鑰與私鑰的應用乾貨
阿新 • • 發佈:2019-01-04
package cn.com.caogen.controller; import java.io.ByteArrayOutputStream; 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.interfaces.RSAPrivateKey; import java.security.interfaces.RSAPublicKey; import java.security.spec.PKCS8EncodedKeySpec; import java.security.spec.X509EncodedKeySpec; import java.util.Date; import java.util.HashMap; import java.util.Map; import javax.crypto.Cipher; import sun.misc.BASE64Decoder; import sun.misc.BASE64Encoder; import static cn.com.caogen.pay.util.RSAEncryption.getPublicKey; public class CreateSecretKey { public static final String KEY_ALGORITHM = "RSA"; private static final String PUBLIC_KEY = "RSAPublicKey"; private static final String PRIVATE_KEY = "RSAPrivateKey"; public static final String SIGNATURE_ALGORITHM = "MD5withRSA"; /** * * RSA最大加密明文大小 * */ private static final int MAX_ENCRYPT_BLOCK = 117; /** * * RSA最大解密密文大小 * */ private static final int MAX_DECRYPT_BLOCK = 128; //獲取公鑰字串 public static String getPublicKeyStr(Map<String, Object> keyMap) throws Exception { //獲得map中的公鑰物件 轉為key物件 Key key = (Key) keyMap.get(PUBLIC_KEY); //編碼返回字串 return encryptBASE64(key.getEncoded()); } //獲得私鑰字串 public static String getPrivateKeyStr(Map<String, Object> keyMap) throws Exception { //獲得map中的私鑰物件 轉為key物件 Key key = (Key) keyMap.get(PRIVATE_KEY); //編碼返回字串 return encryptBASE64(key.getEncoded()); } //獲取公鑰 public static PublicKey getPublicKey(String key) throws Exception { byte[] keyBytes; keyBytes = (new BASE64Decoder()).decodeBuffer(key); X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); PublicKey publicKey = keyFactory.generatePublic(keySpec); return publicKey; } //獲取私鑰 public static PrivateKey getPrivateKey(String key) throws Exception { byte[] keyBytes; keyBytes = (new BASE64Decoder()).decodeBuffer(key); PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); PrivateKey privateKey = keyFactory.generatePrivate(keySpec); return privateKey; } //編碼返回字串 public static String encryptBASE64(byte[] key) throws Exception { return (new BASE64Encoder()).encodeBuffer(key); } //解碼返回byte public static byte[] decryptBASE64(String key) throws Exception { return (new BASE64Decoder()).decodeBuffer(key); } //***************************簽名和驗證******************************* /** * 簽名 * * @param data * @param privateKeyStr * @return * @throws Exception */ public static byte[] sign(byte[] data, String privateKeyStr) throws Exception { PrivateKey priK = getPrivateKey(privateKeyStr); Signature sig = Signature.getInstance(SIGNATURE_ALGORITHM); sig.initSign(priK); sig.update(data); return sig.sign(); } /** * 驗籤 * * @param data * @param sign * @param publicKeyStr * @return * @throws Exception */ public static boolean verify(byte[] data, byte[] sign, String publicKeyStr) throws Exception { PublicKey pubK = getPublicKey(publicKeyStr); Signature sig = Signature.getInstance(SIGNATURE_ALGORITHM); sig.initVerify(pubK); sig.update(data); return sig.verify(sign); } //************************加密解密************************** /** * 公鑰加密 * * @param plainText * @param publicKeyStr * @return * @throws Exception */ public static byte[] encrypt(byte[] plainText, String publicKeyStr) throws Exception { PublicKey publicKey = getPublicKey(publicKeyStr); Cipher cipher = Cipher.getInstance(KEY_ALGORITHM); cipher.init(Cipher.ENCRYPT_MODE, publicKey); int inputLen = plainText.length; ByteArrayOutputStream out = new ByteArrayOutputStream(); int offSet = 0; int i = 0; byte[] cache; while (inputLen - offSet > 0) { if (inputLen - offSet > MAX_ENCRYPT_BLOCK) { cache = cipher.doFinal(plainText, offSet, MAX_ENCRYPT_BLOCK); } else { cache = cipher.doFinal(plainText, offSet, inputLen - offSet); } out.write(cache, 0, cache.length); i++; offSet = i * MAX_ENCRYPT_BLOCK; } byte[] encryptText = out.toByteArray(); out.close(); return encryptText; } /** * 私鑰解密 * * @param encryptText * @param privateKeyStr * @return * @throws Exception */ public static byte[] decrypt(byte[] encryptText, String privateKeyStr) throws Exception { PrivateKey privateKey = getPrivateKey(privateKeyStr); Cipher cipher = Cipher.getInstance(KEY_ALGORITHM); cipher.init(Cipher.DECRYPT_MODE, privateKey); int inputLen = encryptText.length; ByteArrayOutputStream out = new ByteArrayOutputStream(); int offSet = 0; byte[] cache; int i = 0; // 對資料分段解密 while (inputLen - offSet > 0) { if (inputLen - offSet > MAX_DECRYPT_BLOCK) { cache = cipher.doFinal(encryptText, offSet, MAX_DECRYPT_BLOCK); } else { cache = cipher.doFinal(encryptText, offSet, inputLen - offSet); } out.write(cache, 0, cache.length); i++; offSet = i * MAX_DECRYPT_BLOCK; } byte[] plainText = out.toByteArray(); out.close(); return plainText; } public static void main(String[] args) { Map<String, Object> keyMap; byte[] cipherText; String input = "Hello World!"; try { keyMap = initKey();//初始化一對鑰匙 String publicKey = getPublicKeyStr(keyMap); System.out.println("公鑰------------------"); System.out.println(publicKey); String privateKey = getPrivateKeyStr(keyMap); System.out.println("私鑰------------------"); System.out.println(privateKey); System.out.println("測試可行性-------------------"); System.out.println("明文=======" + input); cipherText = encrypt(input.getBytes(), publicKey); //加密後的東西 System.out.println("密文=======" + new String(cipherText)); //開始解密 byte[] plainText = decrypt(cipherText, privateKey); System.out.println("解密後明文===== " + new String(plainText)); System.out.println("驗證簽名-----------"); String str = "被簽名的內容"; System.out.println("\n原文:" + str); byte[] signature = sign(str.getBytes(), privateKey); boolean status = verify(str.getBytes(), signature, publicKey); System.out.println("驗證情況:" + status); } catch (Exception e) { e.printStackTrace(); } } /** * 生成一對鑰匙 * * @return * @throws Exception */ public static Map<String, Object> initKey() throws Exception { KeyPairGenerator keyPairGen = KeyPairGenerator .getInstance(KEY_ALGORITHM); keyPairGen.initialize(1024); KeyPair keyPair = keyPairGen.generateKeyPair(); RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic(); RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate(); Map<String, Object> keyMap = new HashMap<String, Object>(2); keyMap.put(PUBLIC_KEY, publicKey); keyMap.put(PRIVATE_KEY, privateKey); return keyMap; } }