org.bouncycastle.openpgp.operator.jcajce.JcaKeyFingerprintCalculator.java Source code

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Here is the source code for org.bouncycastle.openpgp.operator.jcajce.JcaKeyFingerprintCalculator.java

Source

package org.bouncycastle.openpgp.operator.jcajce;

import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Provider;

import org.bouncycastle.bcpg.BCPGKey;
import org.bouncycastle.bcpg.MPInteger;
import org.bouncycastle.bcpg.PublicKeyPacket;
import org.bouncycastle.bcpg.RSAPublicBCPGKey;
import org.bouncycastle.jcajce.util.DefaultJcaJceHelper;
import org.bouncycastle.jcajce.util.JcaJceHelper;
import org.bouncycastle.jcajce.util.NamedJcaJceHelper;
import org.bouncycastle.jcajce.util.ProviderJcaJceHelper;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.operator.KeyFingerPrintCalculator;

public class JcaKeyFingerprintCalculator implements KeyFingerPrintCalculator {
    private final JcaJceHelper helper;

    /**
     * Base Constructor - use the JCA defaults.
     */
    public JcaKeyFingerprintCalculator() {
        this(new DefaultJcaJceHelper());
    }

    private JcaKeyFingerprintCalculator(JcaJceHelper helper) {
        this.helper = helper;
    }

    /**
     * Sets the provider to use to obtain cryptographic primitives.
     *
     * @param provider the JCA provider to use.
     * @return a new JceKeyFingerprintCalculator supported by the passed in provider.
     */
    public JcaKeyFingerprintCalculator setProvider(Provider provider) {
        return new JcaKeyFingerprintCalculator(new ProviderJcaJceHelper(provider));
    }

    /**
     * Sets the provider to use to obtain cryptographic primitives.
     *
     * @param providerName the name of the JCA provider to use.
     * @return a new JceKeyFingerprintCalculator supported by the passed in named provider.
     */
    public JcaKeyFingerprintCalculator setProvider(String providerName) {
        return new JcaKeyFingerprintCalculator(new NamedJcaJceHelper(providerName));
    }

    public byte[] calculateFingerprint(PublicKeyPacket publicPk) throws PGPException {
        BCPGKey key = publicPk.getKey();

        if (publicPk.getVersion() <= 3) {
            RSAPublicBCPGKey rK = (RSAPublicBCPGKey) key;

            try {
                MessageDigest digest = helper.createMessageDigest("MD5");

                byte[] bytes = new MPInteger(rK.getModulus()).getEncoded();
                digest.update(bytes, 2, bytes.length - 2);

                bytes = new MPInteger(rK.getPublicExponent()).getEncoded();
                digest.update(bytes, 2, bytes.length - 2);

                return digest.digest();
            } catch (NoSuchAlgorithmException e) {
                throw new PGPException("can't find MD5", e);
            } catch (NoSuchProviderException e) {
                throw new PGPException("can't find MD5", e);
            } catch (IOException e) {
                throw new PGPException("can't encode key components: " + e.getMessage(), e);
            }
        } else {
            try {
                byte[] kBytes = publicPk.getEncodedContents();

                MessageDigest digest = helper.createMessageDigest("SHA1");

                digest.update((byte) 0x99);
                digest.update((byte) (kBytes.length >> 8));
                digest.update((byte) kBytes.length);
                digest.update(kBytes);

                return digest.digest();
            } catch (NoSuchAlgorithmException e) {
                throw new PGPException("can't find SHA1", e);
            } catch (NoSuchProviderException e) {
                throw new PGPException("can't find SHA1", e);
            } catch (IOException e) {
                throw new PGPException("can't encode key components: " + e.getMessage(), e);
            }
        }
    }
}