Begin introducing new Decryption API

pgpainless-core/src/main/java/org/pgpainless/decryption_verification/ConsumerOptions.java

@@ -0,0 +1,188 @@
+package org.pgpainless.decryption_verification;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import org.bouncycastle.openpgp.PGPException;
+import org.bouncycastle.openpgp.PGPPublicKeyRing;
+import org.bouncycastle.openpgp.PGPPublicKeyRingCollection;
+import org.bouncycastle.openpgp.PGPSecretKeyRing;
+import org.bouncycastle.openpgp.PGPSecretKeyRingCollection;
+import org.bouncycastle.openpgp.PGPSignature;
+import org.pgpainless.key.protection.SecretKeyRingProtector;
+import org.pgpainless.util.Passphrase;
+
+/**
+ * Options for decryption and signature verification.
+ */
+public class ConsumerOptions {
+
+    private Date verifyNotBefore;
+    private Date verifyNotAfter;
+
+    // Set of verification keys
+    private Set<PGPPublicKeyRing> certificates = new HashSet<>();
+    private Set<PGPSignature> detachedSignatures = new HashSet<>();
+    private MissingPublicKeyCallback missingCertificateCallback = null;
+
+    // Session key for decryption without passphrase/key
+    private byte[] sessionKey = null;
+
+    private final Map<PGPSecretKeyRing, SecretKeyRingProtector> decryptionKeys = new HashMap<>();
+    private final Set<Passphrase> decryptionPassphrases = new HashSet<>();
+
+
+    /**
+     * Consider signatures made before the given timestamp invalid.
+     *
+     * @param timestamp timestamp
+     * @return options
+     */
+    public ConsumerOptions verifyNotBefore(Date timestamp) {
+        this.verifyNotBefore = timestamp;
+        return this;
+    }
+
+    /**
+     * Consider signatures made after the given timestamp invalid.
+     *
+     * @param timestamp timestamp
+     * @return options
+     */
+    public ConsumerOptions verifyNotAfter(Date timestamp) {
+        this.verifyNotAfter = timestamp;
+        return this;
+    }
+
+    /**
+     * Add a certificate (public key ring) for signature verification.
+     *
+     * @param verificationCert certificate for signature verification
+     * @return options
+     */
+    public ConsumerOptions addVerificationCert(PGPPublicKeyRing verificationCert) {
+        this.certificates.add(verificationCert);
+        return this;
+    }
+
+    /**
+     * Add a set of certificates (public key rings) for signature verification.
+     *
+     * @param verificationCerts certificates for signature verification
+     * @return options
+     */
+    public ConsumerOptions addVerificationCerts(PGPPublicKeyRingCollection verificationCerts) {
+        for (PGPPublicKeyRing certificate : verificationCerts) {
+            addVerificationCert(certificate);
+        }
+        return this;
+    }
+
+    /**
+     * Add a detached signature for the signature verification process.
+     *
+     * @param detachedSignature detached signature
+     * @return options
+     */
+    public ConsumerOptions addVerificationOfDetachedSignature(PGPSignature detachedSignature) {
+        detachedSignatures.add(detachedSignature);
+        return this;
+    }
+
+    /**
+     * Set a callback that's used when a certificate (public key) is missing for signature verification.
+     *
+     * @param callback callback
+     * @return options
+     */
+    public ConsumerOptions setMissingCertificateCallback(MissingPublicKeyCallback callback) {
+        this.missingCertificateCallback = callback;
+        return this;
+    }
+
+
+    /**
+     * Attempt decryption using a session key.
+     *
+     * Note: PGPainless does not yet support decryption with session keys.
+     * TODO: Implement
+     *
+     * @see <a href="https://datatracker.ietf.org/doc/html/rfc4880#section-2.1">RFC4880 on Session Keys</a>
+     *
+     * @param sessionKey session key
+     * @return options
+     */
+    public ConsumerOptions setSessionKey(@Nonnull byte[] sessionKey) {
+        this.sessionKey = sessionKey;
+        return this;
+    }
+
+    /**
+     * Add a key for message decryption.
+     * The key is expected to be unencrypted.
+     *
+     * @param key unencrypted key
+     * @return options
+     */
+    public ConsumerOptions addDecryptionKey(@Nonnull PGPSecretKeyRing key) {
+        return addDecryptionKey(key, SecretKeyRingProtector.unprotectedKeys());
+    }
+
+    /**
+     * Add a key for message decryption. If the key is encrypted, the {@link SecretKeyRingProtector} is used to decrypt it
+     * when needed.
+     *
+     * @param key key
+     * @param keyRingProtector protector for the secret key
+     * @return options
+     */
+    public ConsumerOptions addDecryptionKey(@Nonnull PGPSecretKeyRing key, @Nonnull SecretKeyRingProtector keyRingProtector) {
+        decryptionKeys.put(key, keyRingProtector);
+        return this;
+    }
+
+    /**
+     * Add a passphrase for message decryption.
+     *
+     * @param passphrase passphrase
+     * @return options
+     */
+    public ConsumerOptions addDecryptionPassphrase(@Nonnull Passphrase passphrase) {
+        decryptionPassphrases.add(passphrase);
+        return this;
+    }
+
+    public Set<PGPSecretKeyRing> getDecryptionKeys() {
+        return Collections.unmodifiableSet(decryptionKeys.keySet());
+    }
+
+    public Set<Passphrase> getDecryptionPassphrases() {
+        return Collections.unmodifiableSet(decryptionPassphrases);
+    }
+
+    public Set<PGPPublicKeyRing> getCertificates() {
+        return Collections.unmodifiableSet(certificates);
+    }
+
+    public MissingPublicKeyCallback getMissingCertificateCallback() {
+        return missingCertificateCallback;
+    }
+
+    public SecretKeyRingProtector getSecretKeyProtector(PGPSecretKeyRing decryptionKeyRing) {
+        return decryptionKeys.get(decryptionKeyRing);
+    }
+
+    public Set<PGPSignature> getDetachedSignatures() {
+        return Collections.unmodifiableSet(detachedSignatures);
+    }
+}

pgpainless-core/src/main/java/org/pgpainless/decryption_verification/DecryptionBuilder.java

@@ -63,6 +63,15 @@ public class DecryptionBuilder implements DecryptionBuilderInterface {
 
     class DecryptWithImpl implements DecryptWith {
 
+        @Override
+        public DecryptionStream withOptions(ConsumerOptions consumerOptions) throws PGPException, IOException {
+            if (consumerOptions == null) {
+                throw new IllegalArgumentException("Consumer options cannot be null.");
+            }
+
+            return DecryptionStreamFactory.create(inputStream, consumerOptions);
+        }
+
         @Override
         public Verify decryptWith(@Nonnull SecretKeyRingProtector decryptor, @Nonnull PGPSecretKeyRingCollection secretKeyRings) {
             DecryptionBuilder.this.decryptionKeys = secretKeyRings;
@@ -219,8 +228,27 @@ public class DecryptionBuilder implements DecryptionBuilderInterface {
 
         @Override
         public DecryptionStream build() throws IOException, PGPException {
-            return DecryptionStreamFactory.create(inputStream, decryptionKeys, decryptionKeyDecryptor,
-                    decryptionPassphrase, detachedSignatures, verificationKeys, missingPublicKeyCallback);
+            ConsumerOptions options = new ConsumerOptions();
+
+            for (PGPSecretKeyRing decryptionKey : (decryptionKeys != null ? decryptionKeys : Collections.<PGPSecretKeyRing>emptyList())) {
+                options.addDecryptionKey(decryptionKey, decryptionKeyDecryptor);
+            }
+
+            for (PGPPublicKeyRing certificate : (verificationKeys != null ? verificationKeys : Collections.<PGPPublicKeyRing>emptyList())) {
+                options.addVerificationCert(certificate);
+            }
+
+            for (PGPSignature detachedSignature : (detachedSignatures != null ? detachedSignatures : Collections.<PGPSignature>emptyList())) {
+                options.addVerificationOfDetachedSignature(detachedSignature);
+            }
+
+            options.setMissingCertificateCallback(missingPublicKeyCallback);
+
+            if (decryptionPassphrase != null) {
+                options.addDecryptionPassphrase(decryptionPassphrase);
+            }
+
+            return DecryptionStreamFactory.create(inputStream, options);
         }
     }
 }

pgpainless-core/src/main/java/org/pgpainless/decryption_verification/DecryptionBuilderInterface.java

@@ -46,6 +46,8 @@ public interface DecryptionBuilderInterface {
 
     interface DecryptWith {
 
+        DecryptionStream withOptions(ConsumerOptions consumerOptions) throws PGPException, IOException;
+
         /**
          * Decrypt the encrypted data using the secret keys found in the provided {@link PGPSecretKeyRingCollection}.
          * Here it is assumed that the secret keys are not password protected.

pgpainless-core/src/main/java/org/pgpainless/decryption_verification/DecryptionStreamFactory.java

@@ -54,6 +54,7 @@ import org.bouncycastle.openpgp.operator.PGPContentVerifierBuilderProvider;
 import org.bouncycastle.openpgp.operator.PublicKeyDataDecryptorFactory;
 import org.pgpainless.PGPainless;
 import org.pgpainless.algorithm.CompressionAlgorithm;
+import org.pgpainless.algorithm.EncryptionPurpose;
 import org.pgpainless.algorithm.StreamEncoding;
 import org.pgpainless.algorithm.SymmetricKeyAlgorithm;
 import org.pgpainless.exception.MessageNotIntegrityProtectedException;
@@ -62,6 +63,7 @@ import org.pgpainless.exception.UnacceptableAlgorithmException;
 import org.pgpainless.implementation.ImplementationFactory;
 import org.pgpainless.key.OpenPgpV4Fingerprint;
 import org.pgpainless.key.SubkeyIdentifier;
+import org.pgpainless.key.info.KeyRingInfo;
 import org.pgpainless.key.protection.SecretKeyRingProtector;
 import org.pgpainless.key.protection.UnlockSecretKey;
 import org.pgpainless.signature.DetachedSignature;
@@ -75,11 +77,7 @@ public final class DecryptionStreamFactory {
     private static final Level LEVEL = Level.FINE;
     private static final int MAX_RECURSION_DEPTH = 16;
 
-    private final PGPSecretKeyRingCollection decryptionKeys;
-    private final SecretKeyRingProtector decryptionKeyDecryptor;
-    private final Passphrase decryptionPassphrase;
-    private final Set<PGPPublicKeyRing> verificationKeys = new HashSet<>();
-    private final MissingPublicKeyCallback missingPublicKeyCallback;
+    private final ConsumerOptions options;
 
     private final OpenPgpMetadata.Builder resultBuilder = OpenPgpMetadata.getBuilder();
     private static final PGPContentVerifierBuilderProvider verifierBuilderProvider = ImplementationFactory.getInstance().getPGPContentVerifierBuilderProvider();
@@ -87,47 +85,30 @@ public final class DecryptionStreamFactory {
     private final Map<OpenPgpV4Fingerprint, OnePassSignature> verifiableOnePassSignatures = new HashMap<>();
     private final List<IntegrityProtectedInputStream> integrityProtectedStreams = new ArrayList<>();
 
-    private DecryptionStreamFactory(@Nullable PGPSecretKeyRingCollection decryptionKeys,
-                                    @Nullable SecretKeyRingProtector decryptor,
-                                    @Nullable Passphrase decryptionPassphrase,
-                                    @Nullable Set<PGPPublicKeyRing> verificationKeys,
-                                    @Nullable MissingPublicKeyCallback missingPublicKeyCallback) {
-        this.decryptionKeys = decryptionKeys;
-        this.decryptionKeyDecryptor = decryptor;
-        this.decryptionPassphrase = decryptionPassphrase;
-        this.verificationKeys.addAll(verificationKeys != null ? verificationKeys : Collections.emptyList());
-        this.missingPublicKeyCallback = missingPublicKeyCallback;
+    public DecryptionStreamFactory(ConsumerOptions options) {
+        this.options = options;
     }
 
     public static DecryptionStream create(@Nonnull InputStream inputStream,
-                                          @Nullable PGPSecretKeyRingCollection decryptionKeys,
-                                          @Nullable SecretKeyRingProtector decryptor,
-                                          @Nullable Passphrase decryptionPassphrase,
-                                          @Nullable List<PGPSignature> detachedSignatures,
-                                          @Nullable Set<PGPPublicKeyRing> verificationKeys,
-                                          @Nullable MissingPublicKeyCallback missingPublicKeyCallback)
-            throws IOException, PGPException {
-        InputStream pgpInputStream;
-        DecryptionStreamFactory factory = new DecryptionStreamFactory(decryptionKeys, decryptor,
-                decryptionPassphrase, verificationKeys, missingPublicKeyCallback);
+                                          @Nonnull ConsumerOptions options) throws PGPException, IOException {
+        InputStream pgpInputStream = inputStream;
+        DecryptionStreamFactory factory = new DecryptionStreamFactory(options);
 
-        if (detachedSignatures != null) {
-            pgpInputStream = inputStream;
-            for (PGPSignature signature : detachedSignatures) {
-                PGPPublicKeyRing signingKeyRing = factory.findSignatureVerificationKeyRing(signature.getKeyID());
-                if (signingKeyRing == null) {
-                    continue;
-                }
-                PGPPublicKey signingKey = signingKeyRing.getPublicKey(signature.getKeyID());
-                signature.init(ImplementationFactory.getInstance().getPGPContentVerifierBuilderProvider(), signingKey);
-                factory.resultBuilder.addDetachedSignature(
-                        new DetachedSignature(signature, signingKeyRing, new SubkeyIdentifier(signingKeyRing, signature.getKeyID())));
+        for (PGPSignature signature : options.getDetachedSignatures()) {
+            PGPPublicKeyRing signingKeyRing = factory.findSignatureVerificationKeyRing(signature.getKeyID());
+            if (signingKeyRing == null) {
+                continue;
             }
-        } else {
-            PGPObjectFactory objectFactory = new PGPObjectFactory(
-                    PGPUtil.getDecoderStream(inputStream), keyFingerprintCalculator);
-            pgpInputStream = factory.processPGPPackets(objectFactory, 1);
+            PGPPublicKey signingKey = signingKeyRing.getPublicKey(signature.getKeyID());
+            signature.init(ImplementationFactory.getInstance().getPGPContentVerifierBuilderProvider(), signingKey);
+            factory.resultBuilder.addDetachedSignature(
+                    new DetachedSignature(signature, signingKeyRing, new SubkeyIdentifier(signingKeyRing, signature.getKeyID())));
         }
+
+        PGPObjectFactory objectFactory = new PGPObjectFactory(
+                PGPUtil.getDecoderStream(inputStream), keyFingerprintCalculator);
+        pgpInputStream = factory.processPGPPackets(objectFactory, 1);
+
         return new DecryptionStream(pgpInputStream, factory.resultBuilder, factory.integrityProtectedStreams);
     }
 
@@ -210,50 +191,68 @@ public final class DecryptionStreamFactory {
         while (encryptedDataIterator.hasNext()) {
             PGPEncryptedData encryptedData = encryptedDataIterator.next();
 
+            // TODO: Can we just skip non-integrity-protected packages?
             if (!encryptedData.isIntegrityProtected()) {
                 throw new MessageNotIntegrityProtectedException();
             }
+
             // Data is passphrase encrypted
             if (encryptedData instanceof PGPPBEEncryptedData) {
                 PGPPBEEncryptedData pbeEncryptedData = (PGPPBEEncryptedData) encryptedData;
-                if (decryptionPassphrase != null) {
+                for (Passphrase passphrase : options.getDecryptionPassphrases()) {
                     PBEDataDecryptorFactory passphraseDecryptor = ImplementationFactory.getInstance()
-                            .getPBEDataDecryptorFactory(decryptionPassphrase);
-                    SymmetricKeyAlgorithm symmetricKeyAlgorithm = SymmetricKeyAlgorithm.fromId(
-                            pbeEncryptedData.getSymmetricAlgorithm(passphraseDecryptor));
-                    throwIfAlgorithmIsRejected(symmetricKeyAlgorithm);
-                    resultBuilder.setSymmetricKeyAlgorithm(symmetricKeyAlgorithm);
-
+                            .getPBEDataDecryptorFactory(passphrase);
                     try {
-                        return pbeEncryptedData.getDataStream(passphraseDecryptor);
+                        InputStream decryptedDataStream = pbeEncryptedData.getDataStream(passphraseDecryptor);
+
+                        SymmetricKeyAlgorithm symmetricKeyAlgorithm = SymmetricKeyAlgorithm.fromId(
+                                pbeEncryptedData.getSymmetricAlgorithm(passphraseDecryptor));
+                        throwIfAlgorithmIsRejected(symmetricKeyAlgorithm);
+                        resultBuilder.setSymmetricKeyAlgorithm(symmetricKeyAlgorithm);
+
+                        return decryptedDataStream;
                     } catch (PGPException e) {
                         LOGGER.log(LEVEL, "Probable passphrase mismatch, skip PBE encrypted data block", e);
                     }
                 }
             }
+
             // data is public key encrypted
             else if (encryptedData instanceof PGPPublicKeyEncryptedData) {
+                if (options.getDecryptionKeys().isEmpty()) {
+
+                }
                 PGPPublicKeyEncryptedData publicKeyEncryptedData = (PGPPublicKeyEncryptedData) encryptedData;
                 long keyId = publicKeyEncryptedData.getKeyID();
-                if (decryptionKeys != null) {
+                if (!options.getDecryptionKeys().isEmpty()) {
                     // Known key id
                     if (keyId != 0) {
                         LOGGER.log(LEVEL, "PGPEncryptedData is encrypted for key " + Long.toHexString(keyId));
                         resultBuilder.addRecipientKeyId(keyId);
-                        PGPSecretKey secretKey = decryptionKeys.getSecretKey(keyId);
-                        if (secretKey != null) {
+                        PGPSecretKeyRing decryptionKeyRing = findDecryptionKeyRing(keyId);
+                        if (decryptionKeyRing != null) {
+                            PGPSecretKey secretKey = decryptionKeyRing.getSecretKey(keyId);
                             LOGGER.log(LEVEL, "Found respective secret key " + Long.toHexString(keyId));
                             // Watch out! This assignment is possibly done multiple times.
                             encryptedSessionKey = publicKeyEncryptedData;
-                            decryptionKey = UnlockSecretKey.unlockSecretKey(secretKey, decryptionKeyDecryptor);
+                            decryptionKey = UnlockSecretKey.unlockSecretKey(secretKey, options.getSecretKeyProtector(decryptionKeyRing));
                             resultBuilder.setDecryptionFingerprint(new OpenPgpV4Fingerprint(secretKey));
                         }
-                    } else {
-                        // Hidden recipient
+                    }
+
+                    // Hidden recipient
+                    else {
                         LOGGER.log(LEVEL, "Hidden recipient detected. Try to decrypt with all available secret keys.");
-                        outerloop: for (PGPSecretKeyRing ring : decryptionKeys) {
-                            for (PGPSecretKey key : ring) {
-                                PGPPrivateKey privateKey = key.extractPrivateKey(decryptionKeyDecryptor.getDecryptor(key.getKeyID()));
+                        outerloop: for (PGPSecretKeyRing ring : options.getDecryptionKeys()) {
+                            KeyRingInfo info = new KeyRingInfo(ring);
+                            List<PGPPublicKey> encryptionSubkeys = info.getEncryptionSubkeys(EncryptionPurpose.STORAGE_AND_COMMUNICATIONS);
+                            for (PGPPublicKey pubkey : encryptionSubkeys) {
+                                PGPSecretKey key = ring.getSecretKey(pubkey.getKeyID());
+                                if (key == null) {
+                                    continue;
+                                }
+
+                                PGPPrivateKey privateKey = UnlockSecretKey.unlockSecretKey(key, options.getSecretKeyProtector(ring).getDecryptor(key.getKeyID()));
                                 PublicKeyDataDecryptorFactory decryptorFactory = ImplementationFactory.getInstance().getPublicKeyDataDecryptorFactory(privateKey);
                                 try {
                                     publicKeyEncryptedData.getSymmetricAlgorithm(decryptorFactory); // will only succeed if we have the right secret key
@@ -271,7 +270,11 @@ public final class DecryptionStreamFactory {
                 }
             }
         }
+        return decryptWith(encryptedSessionKey, decryptionKey);
+    }
 
+    private InputStream decryptWith(PGPPublicKeyEncryptedData encryptedSessionKey, PGPPrivateKey decryptionKey)
+            throws PGPException {
         if (decryptionKey == null) {
             throw new MissingDecryptionMethodException("Decryption failed - No suitable decryption key or passphrase found");
         }
@@ -339,9 +342,18 @@ public final class DecryptionStreamFactory {
         verifiableOnePassSignatures.put(fingerprint, onePassSignature);
     }
 
+    private PGPSecretKeyRing findDecryptionKeyRing(long keyId) {
+        for (PGPSecretKeyRing key : options.getDecryptionKeys()) {
+            if (key.getSecretKey(keyId) != null) {
+                return key;
+            }
+        }
+        return null;
+    }
+
     private PGPPublicKeyRing findSignatureVerificationKeyRing(long keyId) {
         PGPPublicKeyRing verificationKeyRing = null;
-        for (PGPPublicKeyRing publicKeyRing : verificationKeys) {
+        for (PGPPublicKeyRing publicKeyRing : options.getCertificates()) {
             PGPPublicKey verificationKey = publicKeyRing.getPublicKey(keyId);
             if (verificationKey != null) {
                 LOGGER.log(LEVEL, "Found public key " + Long.toHexString(keyId) + " for signature verification");
@@ -350,8 +362,8 @@ public final class DecryptionStreamFactory {
             }
         }
 
-        if (verificationKeyRing == null && missingPublicKeyCallback != null) {
-            verificationKeyRing = missingPublicKeyCallback.onMissingPublicKeyEncountered(keyId);
+        if (verificationKeyRing == null && options.getMissingCertificateCallback() != null) {
+            verificationKeyRing = options.getMissingCertificateCallback().onMissingPublicKeyEncountered(keyId);
         }
 
         return verificationKeyRing;

pgpainless-core/src/test/java/org/pgpainless/symmetric_encryption/SymmetricEncryptionTest.java

@@ -109,7 +109,7 @@ public class SymmetricEncryptionTest {
 
     @ParameterizedTest
     @MethodSource("org.pgpainless.util.TestUtil#provideImplementationFactories")
-    public void testMissmatchPassphraseFails(ImplementationFactory implementationFactory) throws IOException, PGPException {
+    public void testMismatchPassphraseFails(ImplementationFactory implementationFactory) throws IOException, PGPException {
         ImplementationFactory.setFactoryImplementation(implementationFactory);
 
         byte[] bytes = new byte[5000];