org.springframework.security.jwt.crypto.sign.RsaSigner.java Source code

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Here is the source code for org.springframework.security.jwt.crypto.sign.RsaSigner.java

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/*
 * Copyright 2006-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 * https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */
package org.springframework.security.jwt.crypto.sign;

import java.math.BigInteger;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.spec.RSAPrivateKeySpec;

/**
 * A signer for signing using an RSA private key.
 *
 * The key can be supplied directly, or as an SSH private key string (in
 * the standard format produced by <tt>ssh-keygen</tt>)
 *
 * @author Luke Taylor
 */
public class RsaSigner implements Signer {
    static final String DEFAULT_ALGORITHM = "SHA256withRSA";

    private final RSAPrivateKey key;
    private final String algorithm;

    public RsaSigner(BigInteger n, BigInteger d) {
        this(createPrivateKey(n, d));
    }

    public RsaSigner(RSAPrivateKey key) {
        this(key, DEFAULT_ALGORITHM);
    }

    public RsaSigner(RSAPrivateKey key, String algorithm) {
        this.key = key;
        this.algorithm = algorithm;
    }

    public RsaSigner(String sshKey) {
        this(loadPrivateKey(sshKey));
    }

    public byte[] sign(byte[] bytes) {
        try {
            Signature signature = Signature.getInstance(algorithm);
            signature.initSign(key);
            signature.update(bytes);
            return signature.sign();
        } catch (GeneralSecurityException e) {
            throw new RuntimeException(e);
        }
    }

    public String algorithm() {
        return algorithm;
    }

    private static RSAPrivateKey createPrivateKey(BigInteger n, BigInteger d) {
        try {
            return (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new RSAPrivateKeySpec(n, d));
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    private static RSAPrivateKey loadPrivateKey(String key) {
        KeyPair kp = RsaKeyHelper.parseKeyPair(key);

        if (kp.getPrivate() == null) {
            throw new IllegalArgumentException("Not a private key");
        }

        return (RSAPrivateKey) kp.getPrivate();
    }
}