/*
* Copyright 2013 MovingBlocks
*
* 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
*
* http://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.terasology.identity;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import java.math.BigInteger;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.SecureRandom;
import java.security.Signature;
import java.security.SignatureException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.RSAPrivateKeySpec;
/**
* A private certificate contains the key that only the certificate owner should know. Used for signing and decryption
*/
public class PrivateIdentityCertificate {
private BigInteger modulus;
private BigInteger exponent;
public PrivateIdentityCertificate(BigInteger modulus, BigInteger exponent) {
this.modulus = modulus;
this.exponent = exponent;
}
public BigInteger getModulus() {
return modulus;
}
public BigInteger getExponent() {
return exponent;
}
/**
* Produces a signature for data that can be verified as by the paired public certificate.
*
* @param dataToSign
* @return The signature
*/
public byte[] sign(byte[] dataToSign) {
RSAPrivateKeySpec keySpec = new RSAPrivateKeySpec(modulus, exponent);
Signature signer = null;
try {
signer = Signature.getInstance(IdentityConstants.SIGNATURE_ALGORITHM);
KeyFactory keyFactory = KeyFactory.getInstance(IdentityConstants.CERTIFICATE_ALGORITHM);
PrivateKey key = keyFactory.generatePrivate(keySpec);
signer.initSign(key, new SecureRandom());
signer.update(dataToSign);
return signer.sign();
} catch (NoSuchAlgorithmException | InvalidKeySpecException | InvalidKeyException | SignatureException e) {
throw new RuntimeException("Unexpected exception during signing", e);
}
}
/**
* Decrypts data encrypted by the paired public certificate
*
* @param data
* @return The decrypted data
* @throws BadEncryptedDataException If the data could not be decrypted due to an error with the data.
*/
public byte[] decrypt(byte[] data) throws BadEncryptedDataException {
RSAPrivateKeySpec keySpec = new RSAPrivateKeySpec(modulus, exponent);
try {
KeyFactory keyFactory = KeyFactory.getInstance(IdentityConstants.CERTIFICATE_ALGORITHM);
PrivateKey key = keyFactory.generatePrivate(keySpec);
Cipher cipher = Cipher.getInstance(IdentityConstants.CERTIFICATE_ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, key);
return cipher.doFinal(data);
} catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
throw new RuntimeException("Insufficient support for '" + IdentityConstants.CERTIFICATE_ALGORITHM + "', required for identity management", e);
} catch (InvalidKeySpecException | InvalidKeyException e) {
throw new RuntimeException("Unexpected error during encryption", e);
} catch (BadPaddingException | IllegalBlockSizeException e) {
throw new BadEncryptedDataException("Invalid encrypted data", e);
}
}
}