org.bouncycastle.openpgp.operator.jcajce.JcaPGPContentVerifierBuilderProvider Maven / Gradle / Ivy

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The Bouncy Castle Java APIs for the OpenPGP Protocol. The APIs are designed primarily to be used in conjunction with the BC LTS provider but may also be used with other providers providing cryptographic services.
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package org.bouncycastle.openpgp.operator.jcajce;

import java.io.OutputStream;
import java.security.InvalidKeyException;
import java.security.Provider;
import java.security.PublicKey;
import java.security.Signature;
import java.security.SignatureException;
import java.security.interfaces.RSAPublicKey;

import org.bouncycastle.bcpg.PublicKeyAlgorithmTags;
import org.bouncycastle.jcajce.io.OutputStreamFactory;
import org.bouncycastle.jcajce.util.DefaultJcaJceHelper;
import org.bouncycastle.jcajce.util.NamedJcaJceHelper;
import org.bouncycastle.jcajce.util.ProviderJcaJceHelper;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPPublicKey;
import org.bouncycastle.openpgp.PGPRuntimeOperationException;
import org.bouncycastle.openpgp.operator.PGPContentVerifier;
import org.bouncycastle.openpgp.operator.PGPContentVerifierBuilder;
import org.bouncycastle.openpgp.operator.PGPContentVerifierBuilderProvider;
import org.bouncycastle.openpgp.operator.PGPDigestCalculator;

public class JcaPGPContentVerifierBuilderProvider
    implements PGPContentVerifierBuilderProvider
{
    private OperatorHelper helper = new OperatorHelper(new DefaultJcaJceHelper());
    private JcaPGPDigestCalculatorProviderBuilder digestCalculatorProviderBuilder = new JcaPGPDigestCalculatorProviderBuilder();
    private JcaPGPKeyConverter keyConverter = new JcaPGPKeyConverter();

    public JcaPGPContentVerifierBuilderProvider()
    {
    }

    public JcaPGPContentVerifierBuilderProvider setProvider(Provider provider)
    {
        this.helper = new OperatorHelper(new ProviderJcaJceHelper(provider));
        keyConverter.setProvider(provider);
        digestCalculatorProviderBuilder.setProvider(provider);

        return this;
    }

    public JcaPGPContentVerifierBuilderProvider setProvider(String providerName)
    {
        this.helper = new OperatorHelper(new NamedJcaJceHelper(providerName));
        keyConverter.setProvider(providerName);
        digestCalculatorProviderBuilder.setProvider(providerName);

        return this;
    }

    public PGPContentVerifierBuilder get(int keyAlgorithm, int hashAlgorithm)
        throws PGPException
    {
        return new JcaPGPContentVerifierBuilder(keyAlgorithm, hashAlgorithm);
    }

    private class JcaPGPContentVerifierBuilder
        implements PGPContentVerifierBuilder
    {
        private int hashAlgorithm;
        private int keyAlgorithm;

        public JcaPGPContentVerifierBuilder(int keyAlgorithm, int hashAlgorithm)
        {
            this.keyAlgorithm = keyAlgorithm;
            this.hashAlgorithm = hashAlgorithm;
        }

        public PGPContentVerifier build(final PGPPublicKey publicKey)
            throws PGPException
        {
            final PGPDigestCalculator digestCalculator = digestCalculatorProviderBuilder.build().get(hashAlgorithm);
            final PublicKey jcaKey = keyConverter.getPublicKey(publicKey);

            final Signature signature;
            if (keyAlgorithm == PublicKeyAlgorithmTags.EDDSA_LEGACY && jcaKey.getAlgorithm().equals("Ed448"))
            {
                signature = helper.createSignature(PublicKeyAlgorithmTags.Ed448, hashAlgorithm);
            }
            else
            {
                signature = helper.createSignature(keyAlgorithm, hashAlgorithm);
            }

            try
            {
                signature.initVerify(jcaKey);
            }
            catch (InvalidKeyException e)
            {
                throw new PGPException("invalid key.", e);
            }

            return new PGPContentVerifier()
            {
                private final boolean isEdDsa = keyAlgorithm == PublicKeyAlgorithmTags.EDDSA_LEGACY || keyAlgorithm == PublicKeyAlgorithmTags.Ed448 || keyAlgorithm == PublicKeyAlgorithmTags.Ed25519;

                public int getHashAlgorithm()
                {
                    return hashAlgorithm;
                }

                public int getKeyAlgorithm()
                {
                    return keyAlgorithm;
                }

                public long getKeyID()
                {
                    return publicKey.getKeyID();
                }

                public boolean verify(byte[] expected)
                {
                    try
                    {
                        // an RSA PGP signature is stored as an MPI, this can occasionally result in a short
                        // signature if there is a leading zero.
                        if (jcaKey instanceof RSAPublicKey)
                        {
                            int modLength = (((RSAPublicKey)jcaKey).getModulus().bitLength() + 7) / 8;
                            if (expected.length < modLength)
                            {
                                byte[] tmp = new byte[modLength];

                                System.arraycopy(expected, 0, tmp, tmp.length - expected.length, expected.length);

                                return signature.verify(tmp);
                            }
                        }
                        if (isEdDsa)
                        {
                            signature.update(digestCalculator.getDigest());

                            return signature.verify(expected);
                        }
                        return signature.verify(expected);
                    }
                    catch (SignatureException e)
                    {
                        throw new PGPRuntimeOperationException("unable to verify signature: " + e.getMessage(), e);
                    }
                }

                public OutputStream getOutputStream()
                {
                    if (isEdDsa)
                    {
                        return digestCalculator.getOutputStream();
                    }
                    return OutputStreamFactory.createStream(signature);
                }
            };
        }
    }
}