密码公钥加密私钥解密

public class RSACrytography {

	//生成秘钥对
	public static KeyPair genKeyPair(int keyLength) throws Exception {
		KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
		keyPairGenerator.initialize(keyLength);
		return keyPairGenerator.generateKeyPair();
	}

	//生成字符串的公钥
	public static String getPublicKey(KeyPair keyPair) throws Exception {
		PublicKey publicKey = keyPair.getPublic();
		return new String(Base64.getEncoder().encode(publicKey.getEncoded()));
	}

	//生成字符串的私钥
	public static String getPrivateKey(KeyPair keyPair) throws Exception{
		PrivateKey privateKey = keyPair.getPrivate();
		return new String(Base64.getEncoder().encode(privateKey.getEncoded()));
	}

	//公钥加密
	public static String encrypt(byte[] content, String publicKeyString) throws Exception {
		Cipher cipher = Cipher.getInstance("RSA");
		cipher.init(Cipher.ENCRYPT_MODE,getPublicKey(publicKeyString));
		return new String(Base64.getEncoder().encode(cipher.doFinal(content)));
	}

	//私钥解密
	public static String decrypt(String content, String privateKeyString) throws Exception {
		Cipher cipher = Cipher.getInstance("RSA");
		cipher.init(Cipher.DECRYPT_MODE, getPrivateKey(privateKeyString));
		return new String(cipher.doFinal(Base64.getDecoder().decode(content)));
	}

	//将base64编码后的公钥字符串转成PublicKey实例
	private static PublicKey getPublicKey(String publicKey) throws Exception {
		byte[] keyBytes = Base64.getDecoder().decode(publicKey.getBytes("UTF-8"));
		X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		return keyFactory.generatePublic(keySpc);
	}

	//将base64编码后的私钥字符串转成PprivateKey实例
	private static PrivateKey getPrivateKey(String privateKey) throws Exception{
		byte[] keyBytes = Base64.getDecoder().decode(privateKey.getBytes("UTF-8"));
		PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		return keyFactory.generatePrivate(keySpec);
	}

}