src/main/java/org/bouncycastle/crypto/tls/DefaultTlsEncryptionCredentials.java


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package org.bouncycastle.crypto.tls;

import java.io.IOException;

import org.bouncycastle.crypto.InvalidCipherTextException;
import org.bouncycastle.crypto.encodings.PKCS1Encoding;
import org.bouncycastle.crypto.engines.RSABlindedEngine;
import org.bouncycastle.crypto.params.AsymmetricKeyParameter;
import org.bouncycastle.crypto.params.ParametersWithRandom;
import org.bouncycastle.crypto.params.RSAKeyParameters;

public class DefaultTlsEncryptionCredentials implements TlsEncryptionCredentials {
    protected TlsContext context;
    protected Certificate certificate;
    protected AsymmetricKeyParameter privateKey;

    public DefaultTlsEncryptionCredentials(TlsContext context, Certificate certificate,
        AsymmetricKeyParameter privateKey) {
        if (certificate == null) {
            throw new IllegalArgumentException("'certificate' cannot be null");
        }
        if (certificate.isEmpty()) {
            throw new IllegalArgumentException("'certificate' cannot be empty");
        }
        if (privateKey == null) {
            throw new IllegalArgumentException("'privateKey' cannot be null");
        }
        if (!privateKey.isPrivate()) {
            throw new IllegalArgumentException("'privateKey' must be private");
        }

        if (privateKey instanceof RSAKeyParameters) {
        } else {
            throw new IllegalArgumentException("'privateKey' type not supported: "
                + privateKey.getClass().getName());
        }

        this.context = context;
        this.certificate = certificate;
        this.privateKey = privateKey;
    }

    public Certificate getCertificate() {
        return certificate;
    }

    public byte[] decryptPreMasterSecret(byte[] encryptedPreMasterSecret) throws IOException {

        PKCS1Encoding encoding = new PKCS1Encoding(new RSABlindedEngine());
        encoding.init(false, new ParametersWithRandom(this.privateKey, context.getSecureRandom()));

        try {
            return encoding.processBlock(encryptedPreMasterSecret, 0,
                encryptedPreMasterSecret.length);
        } catch (InvalidCipherTextException e) {
            throw new TlsFatalAlert(AlertDescription.illegal_parameter);
        }
    }
}