1 files changed, 121 insertions, 0 deletions
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/CachedSecretKey.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/CachedSecretKey.java
new file mode 100644
index 000000000..514fca6fb
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/CachedSecretKey.java
@@ -0,0 +1,121 @@
+package org.sufficientlysecure.keychain.pgp;
+
+import org.spongycastle.openpgp.PGPException;
+import org.spongycastle.openpgp.PGPPrivateKey;
+import org.spongycastle.openpgp.PGPSecretKey;
+import org.spongycastle.openpgp.PGPSignature;
+import org.spongycastle.openpgp.PGPSignatureGenerator;
+import org.spongycastle.openpgp.PGPSignatureSubpacketGenerator;
+import org.spongycastle.openpgp.PGPV3SignatureGenerator;
+import org.spongycastle.openpgp.operator.PBESecretKeyDecryptor;
+import org.spongycastle.openpgp.operator.PublicKeyDataDecryptorFactory;
+import org.spongycastle.openpgp.operator.jcajce.JcaPGPContentSignerBuilder;
+import org.spongycastle.openpgp.operator.jcajce.JcePBESecretKeyDecryptorBuilder;
+import org.spongycastle.openpgp.operator.jcajce.JcePublicKeyDataDecryptorFactoryBuilder;
+import org.sufficientlysecure.keychain.Constants;
+import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralException;
+
+public class CachedSecretKey {
+
+    // this is the parent key ring
+    private final CachedSecretKeyRing mRing;
+
+    private final PGPSecretKey mKey;
+    private PGPPrivateKey mPrivateKey = null;
+
+    CachedSecretKey(CachedSecretKeyRing ring, PGPSecretKey key) {
+        mRing = ring;
+        mKey = key;
+    }
+
+    public CachedSecretKeyRing getRing() {
+        return mRing;
+    }
+
+    public void unlock(String passphrase) throws PgpGeneralException {
+        try {
+            PBESecretKeyDecryptor keyDecryptor = new JcePBESecretKeyDecryptorBuilder().setProvider(
+                    Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(passphrase.toCharArray());
+            mPrivateKey = mKey.extractPrivateKey(keyDecryptor);
+        } catch (PGPException e) {
+            throw new PgpGeneralException("error extracting key!", e);
+        }
+        if(mPrivateKey == null) {
+            throw new PgpGeneralException("error extracting key (bad passphrase?)");
+        }
+    }
+
+    public PGPSignatureGenerator getSignatureGenerator(int hashAlgo, boolean cleartext)
+            throws PgpGeneralException {
+        if(mPrivateKey == null) {
+            throw new PrivateKeyNotUnlockedException();
+        }
+
+        // content signer based on signing key algorithm and chosen hash algorithm
+        JcaPGPContentSignerBuilder contentSignerBuilder = new JcaPGPContentSignerBuilder(
+                mKey.getPublicKey().getAlgorithm(), hashAlgo)
+                .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
+
+        int signatureType;
+        if (cleartext) {
+            // for sign-only ascii text
+            signatureType = PGPSignature.CANONICAL_TEXT_DOCUMENT;
+        } else {
+            signatureType = PGPSignature.BINARY_DOCUMENT;
+        }
+
+        try {
+            PGPSignatureGenerator signatureGenerator = new PGPSignatureGenerator(contentSignerBuilder);
+            signatureGenerator.init(signatureType, mPrivateKey);
+
+            PGPSignatureSubpacketGenerator spGen = new PGPSignatureSubpacketGenerator();
+            spGen.setSignerUserID(false, mRing.getPrimaryUserId());
+            signatureGenerator.setHashedSubpackets(spGen.generate());
+            return signatureGenerator;
+        } catch(PGPException e) {
+            throw new PgpGeneralException("Error initializing signature!", e);
+        }
+    }
+
+    public PGPV3SignatureGenerator getV3SignatureGenerator(int hashAlgo, boolean cleartext)
+            throws PgpGeneralException {
+        if(mPrivateKey == null) {
+            throw new PrivateKeyNotUnlockedException();
+        }
+
+        // content signer based on signing key algorithm and chosen hash algorithm
+        JcaPGPContentSignerBuilder contentSignerBuilder = new JcaPGPContentSignerBuilder(
+                mKey.getPublicKey().getAlgorithm(), hashAlgo)
+                .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
+
+        int signatureType;
+        if (cleartext) {
+            // for sign-only ascii text
+            signatureType = PGPSignature.CANONICAL_TEXT_DOCUMENT;
+        } else {
+            signatureType = PGPSignature.BINARY_DOCUMENT;
+        }
+
+        try {
+            PGPV3SignatureGenerator signatureV3Generator = new PGPV3SignatureGenerator(contentSignerBuilder);
+            signatureV3Generator.init(signatureType, mPrivateKey);
+            return signatureV3Generator;
+        } catch(PGPException e) {
+            throw new PgpGeneralException("Error initializing signature!", e);
+        }
+    }
+
+    public PublicKeyDataDecryptorFactory getDecryptorFactory() {
+        if(mPrivateKey == null) {
+            throw new PrivateKeyNotUnlockedException();
+        }
+        return new JcePublicKeyDataDecryptorFactoryBuilder()
+                .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(mPrivateKey);
+    }
+
+    static class PrivateKeyNotUnlockedException extends RuntimeException {
+        // this exception is a programming error which happens when an operation which requires
+        // the private key is called without a previous call to unlock()
+    }
+
+}