从PKCS1密钥中获取RSA公钥

Question

我获得以下格式的公钥，我需要使用java来使用这个密钥加密一些数据。

MIGJAoGBAKDZp/3e4w1nJA/ImDMgaGowWfTnhlFkrvS86LBc6wh1/zBRt51/2F/o/ZzaA5mZ nx5YMlhDOf3vHyzyO4KzYlG8md3RQU7eKQQDxgRfW1v0f7WVQoC2Dxbupyz0JVV4jQStYUYW ifGsh76wI3rkzlq3F2Ea/+jqMxX/AZOO30tBAgMBAAE= --端RSA公钥-

Answer 1

您可以使用BouncyCastle库来实现这一点。你的钥匙在PEM里。要阅读它，可以使用PEMParser：

private static PublicKey readPublicKey(String path) throws InvalidKeySpecException, NoSuchAlgorithmException, IOException {
    PEMParser pemParser = new PEMParser(new FileReader(path));
    Object object = pemParser.readObject();
    SubjectPublicKeyInfo subjectPublicKeyInfo = (SubjectPublicKeyInfo) object;

    RSAKeyParameters rsa = (RSAKeyParameters) PublicKeyFactory.createKey(subjectPublicKeyInfo);

    RSAPublicKeySpec rsaSpec = new RSAPublicKeySpec(rsa.getModulus(), rsa.getExponent());
    KeyFactory kf = KeyFactory.getInstance("RSA", new BouncyCastleProvider());
    return kf.generatePublic(rsaSpec);
}

然后用这个密钥加密：

PublicKey publicKey = readPublicKey("src/main/resources/key.pem");

String dataToEncrypt = "myMessage";
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", new BouncyCastleProvider());
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] encrypted = cipher.doFinal(dataToEncrypt.getBytes(StandardCharsets.UTF_8));

使用版本：bcpkix-jdk15on和bcprov-jdk15on进行测试。