Add PassphraseMapKeyRingProtector

src/main/java/de/vanitasvitae/crypto/pgpainless/key/KeyRingProtectionSettings.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2018 Paul Schaub.
+ *
+ * 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 de.vanitasvitae.crypto.pgpainless.key;
+
+import de.vanitasvitae.crypto.pgpainless.algorithm.HashAlgorithm;
+import de.vanitasvitae.crypto.pgpainless.algorithm.SymmetricKeyAlgorithm;
+
+public class KeyRingProtectionSettings {
+
+    private final SymmetricKeyAlgorithm encryptionAlgorithm;
+    private final HashAlgorithm hashAlgorithm;
+    private final int s2kCount;
+
+    public KeyRingProtectionSettings(SymmetricKeyAlgorithm encryptionAlgorithm, HashAlgorithm hashAlgorithm, int s2kCount) {
+        this.encryptionAlgorithm = encryptionAlgorithm;
+        this.hashAlgorithm = hashAlgorithm;
+        this.s2kCount = s2kCount;
+    }
+
+    public SymmetricKeyAlgorithm getEncryptionAlgorithm() {
+        return encryptionAlgorithm;
+    }
+
+    public HashAlgorithm getHashAlgorithm() {
+        return hashAlgorithm;
+    }
+
+    public int getS2kCount() {
+        return s2kCount;
+    }
+}

src/main/java/de/vanitasvitae/crypto/pgpainless/key/PassphraseMapKeyRingProtector.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2018 Paul Schaub.
+ *
+ * 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 de.vanitasvitae.crypto.pgpainless.key;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.bouncycastle.openpgp.PGPException;
+import org.bouncycastle.openpgp.operator.PBESecretKeyDecryptor;
+import org.bouncycastle.openpgp.operator.PBESecretKeyEncryptor;
+import org.bouncycastle.openpgp.operator.PGPDigestCalculatorProvider;
+import org.bouncycastle.openpgp.operator.bc.BcPBESecretKeyDecryptorBuilder;
+import org.bouncycastle.openpgp.operator.bc.BcPBESecretKeyEncryptorBuilder;
+import org.bouncycastle.openpgp.operator.bc.BcPGPDigestCalculatorProvider;
+
+/**
+ * Implementation of the {@link SecretKeyRingProtector} which holds a map of key ids and their passwords.
+ */
+public class PassphraseMapKeyRingProtector implements SecretKeyRingProtector {
+
+    private static final PGPDigestCalculatorProvider calculatorProvider = new BcPGPDigestCalculatorProvider();
+
+    private final Map<Long, char[]> passphrases = new HashMap<>();
+    private final KeyRingProtectionSettings protectionSettings;
+
+    public PassphraseMapKeyRingProtector(Map<Long, char[]> passphrases, KeyRingProtectionSettings protectionSettings) {
+        this.passphrases.putAll(passphrases);
+        this.protectionSettings = protectionSettings;
+    }
+
+    public void addPassphrase(Long keyId, char[] passphrase) {
+        this.passphrases.put(keyId, passphrase);
+    }
+
+    public void forgetPassphrase(Long keyId) {
+        char[] passphrase = passphrases.get(keyId);
+        // Overwrite the passphrase in memory with zeros
+        for (int i = 0; i < passphrase.length; i++) {
+            passphrase[i] = '0';
+        }
+        passphrases.remove(keyId);
+    }
+
+    @Override
+    public PBESecretKeyDecryptor getDecryptor(Long keyId) {
+        return new BcPBESecretKeyDecryptorBuilder(calculatorProvider).build(passphrases.get(keyId));
+    }
+
+    @Override
+    public PBESecretKeyEncryptor getEncryptor(Long keyId) throws PGPException {
+        return new BcPBESecretKeyEncryptorBuilder(
+                protectionSettings.getEncryptionAlgorithm().getAlgorithmId(),
+                calculatorProvider.get(protectionSettings.getHashAlgorithm().getAlgorithmId()),
+                protectionSettings.getS2kCount())
+                .build(passphrases.get(keyId));
+    }
+}