Merge branch 'master' into encrypted-export

1 files changed, 62 insertions, 415 deletions

diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpDecryptVerifyOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpDecryptVerifyOperation.java
index 055f84b4d..2d28f70e0 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpDecryptVerifyOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpDecryptVerifyOperation.java
@@ -18,13 +18,23 @@
 
 package org.sufficientlysecure.keychain.pgp;
 
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.security.SignatureException;
+import java.util.Date;
+import java.util.Iterator;
+
 import android.content.Context;
 import android.support.annotation.NonNull;
 import android.webkit.MimeTypeMap;
 
 import org.openintents.openpgp.OpenPgpDecryptionResult;
 import org.openintents.openpgp.OpenPgpMetadata;
-import org.openintents.openpgp.OpenPgpSignatureResult;
 import org.spongycastle.bcpg.ArmoredInputStream;
 import org.spongycastle.openpgp.PGPCompressedData;
 import org.spongycastle.openpgp.PGPDataValidationException;
@@ -33,18 +43,14 @@ import org.spongycastle.openpgp.PGPEncryptedDataList;
 import org.spongycastle.openpgp.PGPException;
 import org.spongycastle.openpgp.PGPKeyValidationException;
 import org.spongycastle.openpgp.PGPLiteralData;
-import org.spongycastle.openpgp.PGPOnePassSignature;
-import org.spongycastle.openpgp.PGPOnePassSignatureList;
 import org.spongycastle.openpgp.PGPPBEEncryptedData;
 import org.spongycastle.openpgp.PGPPublicKeyEncryptedData;
-import org.spongycastle.openpgp.PGPSignature;
 import org.spongycastle.openpgp.PGPSignatureList;
 import org.spongycastle.openpgp.PGPUtil;
 import org.spongycastle.openpgp.jcajce.JcaPGPObjectFactory;
 import org.spongycastle.openpgp.operator.PBEDataDecryptorFactory;
 import org.spongycastle.openpgp.operator.PGPDigestCalculatorProvider;
 import org.spongycastle.openpgp.operator.jcajce.CachingDataDecryptorFactory;
-import org.spongycastle.openpgp.operator.jcajce.JcaPGPContentVerifierBuilderProvider;
 import org.spongycastle.openpgp.operator.jcajce.JcaPGPDigestCalculatorProviderBuilder;
 import org.spongycastle.openpgp.operator.jcajce.JcePBEDataDecryptorFactoryBuilder;
 import org.spongycastle.util.encoders.DecoderException;
@@ -68,17 +74,6 @@ import org.sufficientlysecure.keychain.util.Log;
 import org.sufficientlysecure.keychain.util.Passphrase;
 import org.sufficientlysecure.keychain.util.ProgressScaler;
 
-import java.io.BufferedInputStream;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-import java.io.FileNotFoundException;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
-import java.security.SignatureException;
-import java.util.Date;
-import java.util.Iterator;
-
 public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInputParcel> {
 
     public PgpDecryptVerifyOperation(Context context, ProviderHelper providerHelper, Progressable progressable) {
@@ -153,9 +148,7 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
                     // it is ascii armored
                     Log.d(Constants.TAG, "ASCII Armor Header Line: " + aIn.getArmorHeaderLine());
 
-                    if (input.isSignedLiteralData()) {
-                        return verifySignedLiteralData(input, aIn, outputStream, 0);
-                    } else if (aIn.isClearText()) {
+                    if (aIn.isClearText()) {
                         // a cleartext signature, verify it with the other method
                         return verifyCleartextSignature(aIn, outputStream, 0);
                     } else {
@@ -186,133 +179,6 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
         }
     }
 
-    /**Verify signed plaintext data (PGP/INLINE). */
-    @NonNull
-    private DecryptVerifyResult verifySignedLiteralData(
-            PgpDecryptVerifyInputParcel input, InputStream in, OutputStream out, int indent)
-            throws IOException, PGPException {
-        OperationLog log = new OperationLog();
-        log.add(LogType.MSG_VL, indent);
-
-        // thinking that the proof-fetching operation is going to take most of the time
-        updateProgress(R.string.progress_reading_data, 75, 100);
-
-        JcaPGPObjectFactory pgpF = new JcaPGPObjectFactory(in);
-        Object o = pgpF.nextObject();
-        if (o instanceof PGPCompressedData) {
-            log.add(LogType.MSG_DC_CLEAR_DECOMPRESS, indent + 1);
-
-            pgpF = new JcaPGPObjectFactory(((PGPCompressedData) o).getDataStream());
-            o = pgpF.nextObject();
-            updateProgress(R.string.progress_decompressing_data, 80, 100);
-        }
-
-        // all we want to see is a OnePassSignatureList followed by LiteralData
-        if (!(o instanceof PGPOnePassSignatureList)) {
-            log.add(LogType.MSG_VL_ERROR_MISSING_SIGLIST, indent);
-            return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
-        }
-        PGPOnePassSignatureList sigList = (PGPOnePassSignatureList) o;
-
-        // go through all signatures (should be just one), make sure we have
-        //  the key and it matches the one we’re looking for
-        CanonicalizedPublicKeyRing signingRing = null;
-        CanonicalizedPublicKey signingKey = null;
-        int signatureIndex = -1;
-        for (int i = 0; i < sigList.size(); ++i) {
-            try {
-                long sigKeyId = sigList.get(i).getKeyID();
-                signingRing = mProviderHelper.getCanonicalizedPublicKeyRing(
-                        KeyRings.buildUnifiedKeyRingsFindBySubkeyUri(sigKeyId)
-                );
-                signingKey = signingRing.getPublicKey(sigKeyId);
-                signatureIndex = i;
-            } catch (ProviderHelper.NotFoundException e) {
-                Log.d(Constants.TAG, "key not found, trying next signature...");
-            }
-        }
-
-        // there has to be a key, and it has to be the right one
-        if (signingKey == null) {
-            log.add(LogType.MSG_VL_ERROR_MISSING_KEY, indent);
-            Log.d(Constants.TAG, "Failed to find key in signed-literal message");
-            return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
-        }
-
-        String fingerprint = KeyFormattingUtils.convertFingerprintToHex(signingRing.getFingerprint());
-        if (!(input.getRequiredSignerFingerprint().equals(fingerprint))) {
-            log.add(LogType.MSG_VL_ERROR_MISSING_KEY, indent);
-            Log.d(Constants.TAG, "Fingerprint mismatch; wanted " + input.getRequiredSignerFingerprint() +
-                    " got " + fingerprint + "!");
-            return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
-        }
-
-        OpenPgpSignatureResultBuilder signatureResultBuilder = new OpenPgpSignatureResultBuilder();
-
-        PGPOnePassSignature signature = sigList.get(signatureIndex);
-        signatureResultBuilder.initValid(signingRing, signingKey);
-
-        JcaPGPContentVerifierBuilderProvider contentVerifierBuilderProvider =
-                new JcaPGPContentVerifierBuilderProvider()
-                        .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
-        signature.init(contentVerifierBuilderProvider, signingKey.getPublicKey());
-
-        o = pgpF.nextObject();
-
-        if (!(o instanceof PGPLiteralData)) {
-            log.add(LogType.MSG_VL_ERROR_MISSING_LITERAL, indent);
-            return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
-        }
-
-        PGPLiteralData literalData = (PGPLiteralData) o;
-
-        log.add(LogType.MSG_DC_CLEAR_DATA, indent + 1);
-        updateProgress(R.string.progress_decrypting, 85, 100);
-
-        InputStream dataIn = literalData.getInputStream();
-
-        int length;
-        byte[] buffer = new byte[1 << 16];
-        while ((length = dataIn.read(buffer)) > 0) {
-            out.write(buffer, 0, length);
-            signature.update(buffer, 0, length);
-        }
-
-        updateProgress(R.string.progress_verifying_signature, 95, 100);
-        log.add(LogType.MSG_VL_CLEAR_SIGNATURE_CHECK, indent + 1);
-
-        PGPSignatureList signatureList = (PGPSignatureList) pgpF.nextObject();
-        PGPSignature messageSignature = signatureList.get(signatureIndex);
-
-        // Verify signature and check binding signatures
-        boolean validSignature = signature.verify(messageSignature);
-        if (validSignature) {
-            log.add(LogType.MSG_DC_CLEAR_SIGNATURE_OK, indent + 1);
-        } else {
-            log.add(LogType.MSG_DC_CLEAR_SIGNATURE_BAD, indent + 1);
-        }
-        signatureResultBuilder.setValidSignature(validSignature);
-
-        OpenPgpSignatureResult signatureResult = signatureResultBuilder.build();
-
-        if (signatureResult.getResult() != OpenPgpSignatureResult.RESULT_VALID_CONFIRMED
-                && signatureResult.getResult() != OpenPgpSignatureResult.RESULT_VALID_UNCONFIRMED) {
-            log.add(LogType.MSG_VL_ERROR_INTEGRITY_CHECK, indent);
-            return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
-        }
-
-        updateProgress(R.string.progress_done, 100, 100);
-
-        log.add(LogType.MSG_VL_OK, indent);
-
-        // Return a positive result, with metadata and verification info
-        DecryptVerifyResult result = new DecryptVerifyResult(DecryptVerifyResult.RESULT_OK, log);
-        result.setSignatureResult(signatureResult);
-        result.setDecryptionResult(
-                new OpenPgpDecryptionResult(OpenPgpDecryptionResult.RESULT_NOT_ENCRYPTED));
-        return result;
-    }
-
     private static class EncryptStreamResult {
 
         // this is non-null iff an error occured, return directly
@@ -368,7 +234,6 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
             }
         }
 
-        OpenPgpSignatureResultBuilder signatureResultBuilder = new OpenPgpSignatureResultBuilder();
         OpenPgpDecryptionResultBuilder decryptionResultBuilder = new OpenPgpDecryptionResultBuilder();
 
         JcaPGPObjectFactory plainFact;
@@ -415,10 +280,6 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
 
         log.add(LogType.MSG_DC_PREP_STREAMS, indent);
 
-        int signatureIndex = -1;
-        CanonicalizedPublicKeyRing signingRing = null;
-        CanonicalizedPublicKey signingKey = null;
-
         log.add(LogType.MSG_DC_CLEAR, indent);
         indent += 1;
 
@@ -435,58 +296,8 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
             plainFact = fact;
         }
 
-        // resolve leading signature data
-        PGPOnePassSignature signature = null;
-        if (dataChunk instanceof PGPOnePassSignatureList) {
-            log.add(LogType.MSG_DC_CLEAR_SIGNATURE, indent + 1);
-            currentProgress += 2;
-            updateProgress(R.string.progress_processing_signature, currentProgress, 100);
-
-            PGPOnePassSignatureList sigList = (PGPOnePassSignatureList) dataChunk;
-
-            // NOTE: following code is similar to processSignature, but for PGPOnePassSignature
-
-            // go through all signatures
-            // and find out for which signature we have a key in our database
-            for (int i = 0; i < sigList.size(); ++i) {
-                try {
-                    long sigKeyId = sigList.get(i).getKeyID();
-                    signingRing = mProviderHelper.getCanonicalizedPublicKeyRing(
-                            KeyRings.buildUnifiedKeyRingsFindBySubkeyUri(sigKeyId)
-                    );
-                    signingKey = signingRing.getPublicKey(sigKeyId);
-                    signatureIndex = i;
-                } catch (ProviderHelper.NotFoundException e) {
-                    Log.d(Constants.TAG, "key not found, trying next signature...");
-                }
-            }
-
-            if (signingKey != null) {
-                // key found in our database!
-                signature = sigList.get(signatureIndex);
-
-                signatureResultBuilder.initValid(signingRing, signingKey);
-
-                JcaPGPContentVerifierBuilderProvider contentVerifierBuilderProvider =
-                        new JcaPGPContentVerifierBuilderProvider()
-                                .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
-                signature.init(contentVerifierBuilderProvider, signingKey.getPublicKey());
-            } else {
-                // no key in our database -> return "unknown pub key" status including the first key id
-                if (!sigList.isEmpty()) {
-                    signatureResultBuilder.setSignatureAvailable(true);
-                    signatureResultBuilder.setKnownKey(false);
-                    signatureResultBuilder.setKeyId(sigList.get(0).getKeyID());
-                }
-            }
-
-            // check for insecure signing key
-            // TODO: checks on signingRing ?
-            if (signingKey != null && ! PgpSecurityConstants.isSecureKey(signingKey)) {
-                log.add(LogType.MSG_DC_INSECURE_KEY, indent + 1);
-                signatureResultBuilder.setInsecure(true);
-            }
-
+        PgpSignatureChecker signatureChecker = new PgpSignatureChecker(mProviderHelper);
+        if (signatureChecker.initializeOnePassSignature(dataChunk, log, indent +1)) {
             dataChunk = plainFact.nextObject();
         }
 
@@ -567,16 +378,8 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
             return result;
         }
 
-        int endProgress;
-        if (signature != null) {
-            endProgress = 90;
-        } else if (esResult != null && esResult.encryptedData.isIntegrityProtected()) {
-            endProgress = 95;
-        } else {
-            endProgress = 100;
-        }
         ProgressScaler progressScaler =
-                new ProgressScaler(mProgressable, currentProgress, endProgress, 100);
+                new ProgressScaler(mProgressable, currentProgress, 95, 100);
 
         InputStream dataIn = literalData.getInputStream();
 
@@ -592,9 +395,7 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
             }
 
             // update signature buffer if signature is also present
-            if (signature != null) {
-                signature.update(buffer, 0, length);
-            }
+            signatureChecker.updateSignatureData(buffer, 0, length);
 
             // note down first couple of bytes for "magic bytes" file type detection
             if (alreadyWritten == 0) {
@@ -602,7 +403,7 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
             }
 
             alreadyWritten += length;
-
+            // noinspection ConstantConditions, TODO progress
             if (wholeSize > 0) {
                 long progress = 100 * alreadyWritten / wholeSize;
                 // stop at 100% for wrong file sizes...
@@ -611,7 +412,6 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
                 }
                 progressScaler.setProgress((int) progress, 100);
             }
-            // TODO: slow annealing to fake a progress?
         }
 
         // special treatment to detect pgp mime types
@@ -628,28 +428,15 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
         metadata = new OpenPgpMetadata(
                 originalFilename, mimeType, literalData.getModificationTime().getTime(), alreadyWritten, charset);
 
-        if (signature != null) {
-            updateProgress(R.string.progress_verifying_signature, 90, 100);
-            log.add(LogType.MSG_DC_CLEAR_SIGNATURE_CHECK, indent);
-
-            PGPSignatureList signatureList = (PGPSignatureList) plainFact.nextObject();
-            PGPSignature messageSignature = signatureList.get(signatureIndex);
+        if (signatureChecker.isInitialized()) {
 
-            // Verify signature
-            boolean validSignature = signature.verify(messageSignature);
-            if (validSignature) {
-                log.add(LogType.MSG_DC_CLEAR_SIGNATURE_OK, indent + 1);
-            } else {
-                log.add(LogType.MSG_DC_CLEAR_SIGNATURE_BAD, indent + 1);
-            }
+            Object o = plainFact.nextObject();
+            boolean signatureCheckOk = signatureChecker.verifySignatureOnePass(o, log, indent + 1);
 
-            // check for insecure hash algorithms
-            if (!PgpSecurityConstants.isSecureHashAlgorithm(signature.getHashAlgorithm())) {
-                log.add(LogType.MSG_DC_INSECURE_HASH_ALGO, indent + 1);
-                signatureResultBuilder.setInsecure(true);
+            if (!signatureCheckOk) {
+                return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
             }
 
-            signatureResultBuilder.setValidSignature(validSignature);
         }
 
         indent -= 1;
@@ -664,7 +451,7 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
                     log.add(LogType.MSG_DC_ERROR_INTEGRITY_CHECK, indent);
                     return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
                 }
-            } else if (signature == null) {
+            } else if ( ! signatureChecker.isInitialized() ) {
                 // If no signature is present, we *require* an MDC!
                 // Handle missing integrity protection like failed integrity protection!
                 // The MDC packet can be stripped by an attacker!
@@ -681,7 +468,7 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
         DecryptVerifyResult result = new DecryptVerifyResult(DecryptVerifyResult.RESULT_OK, log);
 
         result.setCachedCryptoInputParcel(cryptoInput);
-        result.setSignatureResult(signatureResultBuilder.build());
+        result.setSignatureResult(signatureChecker.getSignatureResult());
         result.setDecryptionResult(decryptionResultBuilder.build());
         result.setDecryptionMetadata(metadata);
 
@@ -692,13 +479,6 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
     private EncryptStreamResult handleEncryptedPacket(PgpDecryptVerifyInputParcel input, CryptoInputParcel cryptoInput,
             PGPEncryptedDataList enc, OperationLog log, int indent, int currentProgress) throws PGPException {
 
-        // TODO is this necessary?
-        /*
-        else if (obj instanceof PGPEncryptedDataList) {
-            enc = (PGPEncryptedDataList) pgpF.nextObject();
-        }
-        */
-
         EncryptStreamResult result = new EncryptStreamResult();
 
         boolean asymmetricPacketFound = false;
@@ -739,11 +519,6 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
                     log.add(LogType.MSG_DC_ASKIP_NO_KEY, indent + 1);
                     continue;
                 }
-                if (secretKeyRing == null) {
-                    // continue with the next packet in the while loop
-                    log.add(LogType.MSG_DC_ASKIP_NO_KEY, indent + 1);
-                    continue;
-                }
 
                 // allow only specific keys for decryption?
                 if (input.getAllowedKeyIds() != null) {
@@ -763,11 +538,6 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
 
                 // get subkey which has been used for this encryption packet
                 secretEncryptionKey = secretKeyRing.getSecretKey(subKeyId);
-                if (secretEncryptionKey == null) {
-                    // should actually never happen, so no need to be more specific.
-                    log.add(LogType.MSG_DC_ASKIP_NO_KEY, indent + 1);
-                    continue;
-                }
 
                 /* secret key exists in database and is allowed! */
                 asymmetricPacketFound = true;
@@ -969,30 +739,31 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
 
         OperationLog log = new OperationLog();
 
-        OpenPgpSignatureResultBuilder signatureResultBuilder = new OpenPgpSignatureResultBuilder();
-
-        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        byte[] clearText;
+        { // read cleartext
+            ByteArrayOutputStream out = new ByteArrayOutputStream();
 
-        updateProgress(R.string.progress_reading_data, 0, 100);
+            updateProgress(R.string.progress_reading_data, 0, 100);
 
-        ByteArrayOutputStream lineOut = new ByteArrayOutputStream();
-        int lookAhead = readInputLine(lineOut, aIn);
-        byte[] lineSep = getLineSeparator();
+            ByteArrayOutputStream lineOut = new ByteArrayOutputStream();
+            int lookAhead = readInputLine(lineOut, aIn);
+            byte[] lineSep = getLineSeparator();
 
-        byte[] line = lineOut.toByteArray();
-        out.write(line, 0, getLengthWithoutSeparator(line));
-        out.write(lineSep);
-
-        while (lookAhead != -1 && aIn.isClearText()) {
-            lookAhead = readInputLine(lineOut, lookAhead, aIn);
-            line = lineOut.toByteArray();
+            byte[] line = lineOut.toByteArray();
             out.write(line, 0, getLengthWithoutSeparator(line));
             out.write(lineSep);
-        }
 
-        out.close();
+            while (lookAhead != -1 && aIn.isClearText()) {
+                lookAhead = readInputLine(lineOut, lookAhead, aIn);
+                line = lineOut.toByteArray();
+                out.write(line, 0, getLengthWithoutSeparator(line));
+                out.write(lineSep);
+            }
+
+            out.close();
+            clearText = out.toByteArray();
+        }
 
-        byte[] clearText = out.toByteArray();
         if (outputStream != null) {
             outputStream.write(clearText);
             outputStream.close();
@@ -1001,51 +772,20 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
         updateProgress(R.string.progress_processing_signature, 60, 100);
         JcaPGPObjectFactory pgpFact = new JcaPGPObjectFactory(aIn);
 
-        PGPSignatureList sigList = (PGPSignatureList) pgpFact.nextObject();
-        if (sigList == null) {
+        PgpSignatureChecker signatureChecker = new PgpSignatureChecker(mProviderHelper);
+
+        Object o = pgpFact.nextObject();
+        if (!signatureChecker.initializeSignature(o, log, indent+1)) {
             log.add(LogType.MSG_DC_ERROR_INVALID_DATA, 0);
             return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
         }
 
-        PGPSignature signature = processPGPSignatureList(sigList, signatureResultBuilder, log, indent);
-
-        if (signature != null) {
+        if (signatureChecker.isInitialized()) {
             try {
                 updateProgress(R.string.progress_verifying_signature, 90, 100);
-                log.add(LogType.MSG_DC_CLEAR_SIGNATURE_CHECK, indent);
-
-                InputStream sigIn = new BufferedInputStream(new ByteArrayInputStream(clearText));
-
-                lookAhead = readInputLine(lineOut, sigIn);
-
-                processLine(signature, lineOut.toByteArray());
 
-                if (lookAhead != -1) {
-                    do {
-                        lookAhead = readInputLine(lineOut, lookAhead, sigIn);
-
-                        signature.update((byte) '\r');
-                        signature.update((byte) '\n');
-
-                        processLine(signature, lineOut.toByteArray());
-                    } while (lookAhead != -1);
-                }
-
-                // Verify signature and check binding signatures
-                boolean validSignature = signature.verify();
-                if (validSignature) {
-                    log.add(LogType.MSG_DC_CLEAR_SIGNATURE_OK, indent + 1);
-                } else {
-                    log.add(LogType.MSG_DC_CLEAR_SIGNATURE_BAD, indent + 1);
-                }
-
-                // check for insecure hash algorithms
-                if (!PgpSecurityConstants.isSecureHashAlgorithm(signature.getHashAlgorithm())) {
-                    log.add(LogType.MSG_DC_INSECURE_HASH_ALGO, indent + 1);
-                    signatureResultBuilder.setInsecure(true);
-                }
-
-                signatureResultBuilder.setValidSignature(validSignature);
+                signatureChecker.updateSignatureWithCleartext(clearText);
+                signatureChecker.verifySignature(log, indent);
 
             } catch (SignatureException e) {
                 Log.d(Constants.TAG, "SignatureException", e);
@@ -1064,7 +804,7 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
                 clearText.length);
 
         DecryptVerifyResult result = new DecryptVerifyResult(DecryptVerifyResult.RESULT_OK, log);
-        result.setSignatureResult(signatureResultBuilder.build());
+        result.setSignatureResult(signatureChecker.getSignatureResult());
         result.setDecryptionResult(
                 new OpenPgpDecryptionResult(OpenPgpDecryptionResult.RESULT_NOT_ENCRYPTED));
         result.setDecryptionMetadata(metadata);
@@ -1078,30 +818,28 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
 
         OperationLog log = new OperationLog();
 
-        OpenPgpSignatureResultBuilder signatureResultBuilder = new OpenPgpSignatureResultBuilder();
-
         updateProgress(R.string.progress_processing_signature, 0, 100);
         InputStream detachedSigIn = new ByteArrayInputStream(input.getDetachedSignature());
         detachedSigIn = PGPUtil.getDecoderStream(detachedSigIn);
 
         JcaPGPObjectFactory pgpFact = new JcaPGPObjectFactory(detachedSigIn);
 
-        PGPSignatureList sigList;
         Object o = pgpFact.nextObject();
         if (o instanceof PGPCompressedData) {
             PGPCompressedData c1 = (PGPCompressedData) o;
             pgpFact = new JcaPGPObjectFactory(c1.getDataStream());
-            sigList = (PGPSignatureList) pgpFact.nextObject();
-        } else if (o instanceof PGPSignatureList) {
-            sigList = (PGPSignatureList) o;
-        } else {
+            o = pgpFact.nextObject();
+        }
+
+        PgpSignatureChecker signatureChecker = new PgpSignatureChecker(mProviderHelper);
+
+        if ( ! signatureChecker.initializeSignature(o, log, indent+1)) {
             log.add(LogType.MSG_DC_ERROR_INVALID_DATA, 0);
             return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
         }
 
-        PGPSignature signature = processPGPSignatureList(sigList, signatureResultBuilder, log, indent);
+        if (signatureChecker.isInitialized()) {
 
-        if (signature != null) {
             updateProgress(R.string.progress_reading_data, 60, 100);
 
             ProgressScaler progressScaler = new ProgressScaler(mProgressable, 60, 90, 100);
@@ -1116,7 +854,7 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
                 }
 
                 // update signature buffer if signature is also present
-                signature.update(buffer, 0, length);
+                signatureChecker.updateSignatureData(buffer, 0, length);
 
                 alreadyWritten += length;
                 if (wholeSize > 0) {
@@ -1127,105 +865,28 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
                     }
                     progressScaler.setProgress((int) progress, 100);
                 }
-                // TODO: slow annealing to fake a progress?
             }
 
             updateProgress(R.string.progress_verifying_signature, 90, 100);
             log.add(LogType.MSG_DC_CLEAR_SIGNATURE_CHECK, indent);
 
-            // Verify signature and check binding signatures
-            boolean validSignature = signature.verify();
-            if (validSignature) {
-                log.add(LogType.MSG_DC_CLEAR_SIGNATURE_OK, indent + 1);
-            } else {
-                log.add(LogType.MSG_DC_CLEAR_SIGNATURE_BAD, indent + 1);
-            }
-
-            // check for insecure hash algorithms
-            if (!PgpSecurityConstants.isSecureHashAlgorithm(signature.getHashAlgorithm())) {
-                log.add(LogType.MSG_DC_INSECURE_HASH_ALGO, indent + 1);
-                signatureResultBuilder.setInsecure(true);
-            }
+            signatureChecker.verifySignature(log, indent);
 
-            signatureResultBuilder.setValidSignature(validSignature);
         }
 
         updateProgress(R.string.progress_done, 100, 100);
 
         log.add(LogType.MSG_DC_OK, indent);
 
+        // TODO return metadata object?
+
         DecryptVerifyResult result = new DecryptVerifyResult(DecryptVerifyResult.RESULT_OK, log);
-        result.setSignatureResult(signatureResultBuilder.build());
+        result.setSignatureResult(signatureChecker.getSignatureResult());
         result.setDecryptionResult(
                 new OpenPgpDecryptionResult(OpenPgpDecryptionResult.RESULT_NOT_ENCRYPTED));
         return result;
     }
 
-    private PGPSignature processPGPSignatureList(
-            PGPSignatureList sigList, OpenPgpSignatureResultBuilder signatureResultBuilder,
-            OperationLog log, int indent)
-            throws PGPException {
-        CanonicalizedPublicKeyRing signingRing = null;
-        CanonicalizedPublicKey signingKey = null;
-        int signatureIndex = -1;
-
-        // go through all signatures
-        // and find out for which signature we have a key in our database
-        for (int i = 0; i < sigList.size(); ++i) {
-            try {
-                long sigKeyId = sigList.get(i).getKeyID();
-                signingRing = mProviderHelper.getCanonicalizedPublicKeyRing(
-                        KeyRings.buildUnifiedKeyRingsFindBySubkeyUri(sigKeyId)
-                );
-                signingKey = signingRing.getPublicKey(sigKeyId);
-                signatureIndex = i;
-            } catch (ProviderHelper.NotFoundException e) {
-                Log.d(Constants.TAG, "key not found, trying next signature...");
-            }
-        }
-
-        PGPSignature signature = null;
-
-        if (signingKey != null) {
-            // key found in our database!
-            signature = sigList.get(signatureIndex);
-
-            signatureResultBuilder.initValid(signingRing, signingKey);
-
-            JcaPGPContentVerifierBuilderProvider contentVerifierBuilderProvider =
-                    new JcaPGPContentVerifierBuilderProvider()
-                            .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
-            signature.init(contentVerifierBuilderProvider, signingKey.getPublicKey());
-        } else {
-            // no key in our database -> return "unknown pub key" status including the first key id
-            if (!sigList.isEmpty()) {
-                signatureResultBuilder.setSignatureAvailable(true);
-                signatureResultBuilder.setKnownKey(false);
-                signatureResultBuilder.setKeyId(sigList.get(0).getKeyID());
-            }
-        }
-
-        // check for insecure signing key
-        // TODO: checks on signingRing ?
-        if (signingKey != null && ! PgpSecurityConstants.isSecureKey(signingKey)) {
-            log.add(LogType.MSG_DC_INSECURE_KEY, indent + 1);
-            signatureResultBuilder.setInsecure(true);
-        }
-
-        return signature;
-    }
-
-    /**
-     * Mostly taken from ClearSignedFileProcessor in Bouncy Castle
-     */
-    private static void processLine(PGPSignature sig, byte[] line)
-            throws SignatureException {
-        int length = getLengthWithoutWhiteSpace(line);
-        if (length > 0) {
-            sig.update(line, 0, length);
-        }
-    }
-
     private static int readInputLine(ByteArrayOutputStream bOut, InputStream fIn)
             throws IOException {
         bOut.reset();
@@ -1291,20 +952,6 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
         return b == '\r' || b == '\n';
     }
 
-    private static int getLengthWithoutWhiteSpace(byte[] line) {
-        int end = line.length - 1;
-
-        while (end >= 0 && isWhiteSpace(line[end])) {
-            end--;
-        }
-
-        return end + 1;
-    }
-
-    private static boolean isWhiteSpace(byte b) {
-        return b == '\r' || b == '\n' || b == '\t' || b == ' ';
-    }
-
     private static byte[] getLineSeparator() {
         String nl = System.getProperty("line.separator");
         return nl.getBytes();