rsa公鑰私鑰生成工具

RSA工具類，支持長度為2048的秘鑰

public class RSAUtils {
/**
* 加密算法RSA
/
private static final String KEY_ALGORITHM = "RSA";
/*
* 簽名算法
/
private static final String SIGNATURE_ALGORITHM = "SHA256withRSA";
/*
* 獲取公鑰的key
/
private static final String PUBLIC_KEY = "RSAPublicKey";
/*
* 獲取私鑰的key
/
private static final String PRIVATE_KEY = "RSAPrivateKey";
/*
* 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 = 256;
/*
* @param keySize 生成的秘鑰長度 一般為1024或2048
* @return
* @throws Exception
/
public static Map<String, Object> genKeyPair(int keySize){
KeyPairGenerator keyPairGen = null;
try {
keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
} catch (NoSuchAlgorithmException e) {
log.error(String.format("生密鑰異常%s", ExceptionUtils.getStackTrace(e)));
throw new GlobalException(BasicCodeMsg.SERVER_ERROR);
}
keyPairGen.initialize(keySize);
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);
log.info("publicKey：" + Base64.encode(publicKey.getEncoded()));
log.info("privateKey：" + Base64.encode(privateKey.getEncoded()));
return keyMap;
}
/*
* 對已加密數據進行簽名
*
* @param data 已加密的數據
* @param privateKey 私鑰
* @return 對已加密數據生成的簽名
* @throws Exception
/
public static String sign(byte[] data, String privateKey) throws Exception {
byte[] keyBytes = Base64.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initSign(privateK);
signature.update(data);
return Base64.encode(signature.sign());
}
/*
* 驗簽
*
* @param data 簽名之前的數據
* @param publicKey 公鑰
* @param sign 簽名之后的數據
* @return 驗簽是否成功
* @throws Exception
/
public static boolean verify(byte[] data, String publicKey, String sign) throws Exception {
byte[] keyBytes = Base64.decode(publicKey);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
PublicKey publicK = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initVerify(publicK);
signature.update(data);
return signature.verify(Base64.decode(sign));
}
/*
* 用私鑰對數據進行解密
*
* @param encryptedData 使用公鑰加密過的數據
* @param privateKey 私鑰
* @return 解密后的數據
* @throws Exception
/
public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey) throws Exception {
byte[] keyBytes = Base64.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
//Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
Cipher cipher = Cipher.getInstance(KEY_ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, privateK);
int inputLen = encryptedData.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 對數據分段解密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
} else {
cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
return decryptedData;
}
/*
* 公鑰解密
*
* @param encryptedData 使用私鑰加密過的數據
* @param publicKey 公鑰
* @return 解密后的數據
* @throws Exception
/
public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey) throws Exception {
byte[] keyBytes = Base64.decode(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicK = keyFactory.generatePublic(x509KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, publicK);
int inputLen = encryptedData.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 對數據分段解密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
} else {
cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
return decryptedData;
}
/*
* 公鑰加密
*
* @param data 需要加密的數據
* @param publicKey 公鑰
* @return 使用公鑰加密后的數據
* @throws Exception
/
public static byte[] encryptByPublicKey(byte[] data, String publicKey) throws Exception {
byte[] keyBytes = Base64.decode(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicK = keyFactory.generatePublic(x509KeySpec);
// 對數據加密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, publicK);
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 對數據分段加密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
} else {
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
}
byte[] encryptedData = out.toByteArray();
out.close();
return encryptedData;
}
/*
* 私鑰加密
*
* @param data 待加密的數據
* @param privateKey 私鑰
* @return 使用私鑰加密后的數據
* @throws Exception
/
public static byte[] encryptByPrivateKey(byte[] data, String privateKey) throws Exception {
byte[] keyBytes = Base64.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, privateK);
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 對數據分段加密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
} else {
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
}
byte[] encryptedData = out.toByteArray();
out.close();
return encryptedData;
}
/*
* 獲取私鑰
*
* @param keyMap 生成的秘鑰對
* @return
* @throws Exception
/
public static String getPrivateKey(Map<String, Object> keyMap){
Key key = (Key) keyMap.get(PRIVATE_KEY);
return Base64.encode(key.getEncoded());
}
/*
* 獲取公鑰
*
* @param keyMap 生成的秘鑰對
* @return
* @throws Exception
*/
public static String getPublicKey(Map<String, Object> keyMap) {
Key key = (Key) keyMap.get(PUBLIC_KEY);
return Base64.encode(key.getEncoded());
}
}
測試結果：

 public static void main(String[] args) {
        //生成平臺密鑰
        Map<String, Object> keyPair = RSAUtils.genKeyPair(2048);
    }
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