added a "force V3 signature" setting similar to the GPG version, hopefully making APG useful for some special cases where that is needed

Update issue 39
Two new strings:
<string name="section_advanced">Advanced</string>
<string name="label_forceV3Signature">Force V3 Signatures</string>

"V3" is just "version 3" and should remain untranslated, both strings can be seen at the bottom of the preferences activity.

res/values/strings.xml

@@ -46,6 +46,7 @@
     <string name="section_keys">Keys</string>
     <string name="section_general">General</string>
     <string name="section_defaults">Defaults</string>
+    <string name="section_advanced">Advanced</string>
 
     <!-- btn_lowerCase: capitalized words, no punctuation -->
     <string name="btn_signToClipboard">Sign To Clipboard</string>
@@ -106,6 +107,7 @@
     <string name="label_messageCompression">Message Compression</string>
     <string name="label_fileCompression">File Compression</string>
     <string name="label_language">Language</string>
+    <string name="label_forceV3Signature">Force V3 Signatures</string>
 
     <string name="noKeysSelected">Select</string>
     <string name="oneKeySelected">1 Selected</string>

res/xml/apg_preferences.xml

@@ -66,4 +66,14 @@
 
     </PreferenceCategory>
 
+    <PreferenceCategory
+        android:title="@string/section_advanced">
+
+        <CheckBoxPreference
+            android:persistent="false"
+            android:key="forceV3Signatures"
+            android:title="@string/label_forceV3Signature" />
+
+    </PreferenceCategory>
+
 </PreferenceScreen>

src/org/thialfihar/android/apg/Apg.java

@@ -78,6 +78,7 @@ import org.bouncycastle2.openpgp.PGPSignatureList;
 import org.bouncycastle2.openpgp.PGPSignatureSubpacketGenerator;
 import org.bouncycastle2.openpgp.PGPSignatureSubpacketVector;
 import org.bouncycastle2.openpgp.PGPUtil;
+import org.bouncycastle2.openpgp.PGPV3SignatureGenerator;
 import org.thialfihar.android.apg.provider.DataProvider;
 import org.thialfihar.android.apg.provider.Database;
 import org.thialfihar.android.apg.provider.KeyRings;
@@ -1123,6 +1124,7 @@ public class Apg {
                                String signaturePassPhrase,
                                ProgressDialogUpdater progress,
                                int symmetricAlgorithm, int hashAlgorithm, int compression,
+                               boolean forceV3Signature,
                                String passPhrase)
             throws IOException, GeneralException, PGPException, NoSuchProviderException,
             NoSuchAlgorithmException, SignatureException {
@@ -1165,7 +1167,6 @@ public class Apg {
                                                                new BouncyCastleProvider());
         }
 
-        PGPSignatureGenerator signatureGenerator = null;
         progress.setProgress(R.string.progress_preparingStreams, 5, 100);
         // encrypt and compress input file content
         PGPEncryptedDataGenerator cPk =
@@ -1184,18 +1185,29 @@ public class Apg {
         }
         encryptOut = cPk.open(out, new byte[1 << 16]);
 
+        PGPSignatureGenerator signatureGenerator = null;
+        PGPV3SignatureGenerator signatureV3Generator = null;
+
         if (signatureKeyId != 0) {
             progress.setProgress(R.string.progress_preparingSignature, 10, 100);
-            signatureGenerator =
+            if (forceV3Signature) {
-                    new PGPSignatureGenerator(signingKey.getPublicKey().getAlgorithm(),
+                signatureV3Generator =
-                                              hashAlgorithm,
+                    new PGPV3SignatureGenerator(signingKey.getPublicKey().getAlgorithm(),
-                                              new BouncyCastleProvider());
+                                                hashAlgorithm,
-            signatureGenerator.initSign(PGPSignature.BINARY_DOCUMENT, signaturePrivateKey);
+                                                new BouncyCastleProvider());
-            String userId = getMainUserId(getMasterKey(signingKeyRing));
+                signatureV3Generator.initSign(PGPSignature.BINARY_DOCUMENT, signaturePrivateKey);
+            } else {
+                signatureGenerator =
+                        new PGPSignatureGenerator(signingKey.getPublicKey().getAlgorithm(),
+                                                  hashAlgorithm,
+                                                  new BouncyCastleProvider());
+                signatureGenerator.initSign(PGPSignature.BINARY_DOCUMENT, signaturePrivateKey);
 
-            PGPSignatureSubpacketGenerator spGen = new PGPSignatureSubpacketGenerator();
+                String userId = getMainUserId(getMasterKey(signingKeyRing));
-            spGen.setSignerUserID(false, userId);
+                PGPSignatureSubpacketGenerator spGen = new PGPSignatureSubpacketGenerator();
-            signatureGenerator.setHashedSubpackets(spGen.generate());
+                spGen.setSignerUserID(false, userId);
+                signatureGenerator.setHashedSubpackets(spGen.generate());
+            }
         }
 
         PGPCompressedDataGenerator compressGen = null;
@@ -1207,7 +1219,11 @@ public class Apg {
             bcpgOut = new BCPGOutputStream(compressGen.open(encryptOut));
         }
         if (signatureKeyId != 0) {
-            signatureGenerator.generateOnePassVersion(false).encode(bcpgOut);
+            if (forceV3Signature) {
+                signatureV3Generator.generateOnePassVersion(false).encode(bcpgOut);
+            } else {
+                signatureGenerator.generateOnePassVersion(false).encode(bcpgOut);
+            }
         }
 
         PGPLiteralDataGenerator literalGen = new PGPLiteralDataGenerator();
@@ -1223,7 +1239,11 @@ public class Apg {
         while ((n = in.read(buffer)) > 0) {
             pOut.write(buffer, 0, n);
             if (signatureKeyId != 0) {
-                signatureGenerator.update(buffer, 0, n);
+                if (forceV3Signature) {
+                    signatureV3Generator.update(buffer, 0, n);
+                } else {
+                    signatureGenerator.update(buffer, 0, n);
+                }
             }
             done += n;
             if (data.getSize() != 0) {
@@ -1235,7 +1255,11 @@ public class Apg {
 
         if (signatureKeyId != 0) {
             progress.setProgress(R.string.progress_generatingSignature, 95, 100);
-            signatureGenerator.generate().encode(pOut);
+            if (forceV3Signature) {
+                signatureV3Generator.generate().encode(pOut);
+            } else {
+                signatureGenerator.generate().encode(pOut);
+            }
         }
         if (compressGen != null) {
             compressGen.close();
@@ -1252,6 +1276,7 @@ public class Apg {
                                 InputData data, OutputStream outStream,
                                 long signatureKeyId, String signaturePassPhrase,
                                 int hashAlgorithm,
+                                boolean forceV3Signature,
                                 ProgressDialogUpdater progress)
             throws GeneralException, PGPException, IOException, NoSuchAlgorithmException,
             SignatureException {
@@ -1281,20 +1306,30 @@ public class Apg {
                 signingKey.extractPrivateKey(signaturePassPhrase.toCharArray(),
                                              new BouncyCastleProvider());
 
-        PGPSignatureGenerator signatureGenerator = null;
         progress.setProgress(R.string.progress_preparingStreams, 0, 100);
 
         progress.setProgress(R.string.progress_preparingSignature, 30, 100);
-        signatureGenerator =
-                new PGPSignatureGenerator(signingKey.getPublicKey().getAlgorithm(),
-                                          hashAlgorithm,
-                                          new BouncyCastleProvider());
-        signatureGenerator.initSign(PGPSignature.CANONICAL_TEXT_DOCUMENT, signaturePrivateKey);
-        String userId = getMainUserId(getMasterKey(signingKeyRing));
 
-        PGPSignatureSubpacketGenerator spGen = new PGPSignatureSubpacketGenerator();
+        PGPSignatureGenerator signatureGenerator = null;
-        spGen.setSignerUserID(false, userId);
+        PGPV3SignatureGenerator signatureV3Generator = null;
-        signatureGenerator.setHashedSubpackets(spGen.generate());
+        if (forceV3Signature) {
+            signatureV3Generator =
+                new PGPV3SignatureGenerator(signingKey.getPublicKey().getAlgorithm(),
+                                            hashAlgorithm,
+                                            new BouncyCastleProvider());
+            signatureV3Generator.initSign(PGPSignature.CANONICAL_TEXT_DOCUMENT, signaturePrivateKey);
+        } else {
+            signatureGenerator =
+                    new PGPSignatureGenerator(signingKey.getPublicKey().getAlgorithm(),
+                                              hashAlgorithm,
+                                              new BouncyCastleProvider());
+            signatureGenerator.initSign(PGPSignature.CANONICAL_TEXT_DOCUMENT, signaturePrivateKey);
+
+            PGPSignatureSubpacketGenerator spGen = new PGPSignatureSubpacketGenerator();
+            String userId = getMainUserId(getMasterKey(signingKeyRing));
+            spGen.setSignerUserID(false, userId);
+            signatureGenerator.setHashedSubpackets(spGen.generate());
+        }
 
         progress.setProgress(R.string.progress_signing, 40, 100);
 
@@ -1304,16 +1339,29 @@ public class Apg {
         InputStream inStream = data.getInputStream();
         int lookAhead = readInputLine(lineOut, inStream);
 
-        processLine(armorOut, signatureGenerator, lineOut.toByteArray());
+        if (forceV3Signature) {
+            processLine(armorOut, signatureV3Generator, lineOut.toByteArray());
+        } else {
+            processLine(armorOut, signatureGenerator, lineOut.toByteArray());
+        }
 
         if (lookAhead != -1) {
             do {
                 lookAhead = readInputLine(lineOut, lookAhead, inStream);
 
-                signatureGenerator.update((byte)'\r');
+                if (forceV3Signature) {
-                signatureGenerator.update((byte)'\n');
+                    signatureV3Generator.update((byte)'\r');
+                    signatureV3Generator.update((byte)'\n');
+                } else {
+                    signatureGenerator.update((byte)'\r');
+                    signatureGenerator.update((byte)'\n');
+                }
 
-                processLine(armorOut, signatureGenerator, lineOut.toByteArray());
+                if (forceV3Signature) {
+                    processLine(armorOut, signatureV3Generator, lineOut.toByteArray());
+                } else {
+                    processLine(armorOut, signatureGenerator, lineOut.toByteArray());
+                }
             }
             while (lookAhead != -1);
         }
@@ -1321,7 +1369,11 @@ public class Apg {
         armorOut.endClearText();
 
         BCPGOutputStream bOut = new BCPGOutputStream(armorOut);
-        signatureGenerator.generate().encode(bOut);
+        if (forceV3Signature) {
+            signatureV3Generator.generate().encode(bOut);
+        } else {
+            signatureGenerator.generate().encode(bOut);
+        }
         armorOut.close();
 
         progress.setProgress(R.string.progress_done, 100, 100);
@@ -1802,6 +1854,16 @@ public class Apg {
         aOut.write(line, 0, line.length);
     }
 
+    private static void processLine(OutputStream aOut, PGPV3SignatureGenerator sGen, byte[] line)
+        throws SignatureException, IOException {
+        int length = getLengthWithoutWhiteSpace(line);
+        if (length > 0) {
+            sGen.update(line, 0, length);
+        }
+
+        aOut.write(line, 0, line.length);
+}
+
     private static int getLengthWithoutSeparator(byte[] line) {
         int end = line.length - 1;
 

src/org/thialfihar/android/apg/Constants.java

@@ -33,5 +33,6 @@ public final class Constants {
         public static final String default_file_compression = "defaultFileCompression";
         public static final String pass_phrase_cache_ttl = "passPhraseCacheTtl";
         public static final String language = "language";
+        public static final String force_v3_signatures = "forceV3Signatures";
     }
 }

src/org/thialfihar/android/apg/EncryptActivity.java

@@ -619,16 +619,15 @@ public class EncryptActivity extends BaseActivity {
         String error = null;
         Bundle data = new Bundle();
         Message msg = new Message();
-        fillDataSource();
+
-        fillDataDestination();
         try {
             InputData in;
             OutputStream out;
             boolean useAsciiArmour = true;
             long encryptionKeyIds[] = null;
             long signatureKeyId = 0;
-            boolean signOnly = false;
             int compressionId = 0;
+            boolean signOnly = false;
 
             String passPhrase = null;
             if (mMode.getCurrentView().getId() == R.id.modeSymmetric) {
@@ -642,6 +641,9 @@ public class EncryptActivity extends BaseActivity {
                 signOnly = (mEncryptionKeyIds == null || mEncryptionKeyIds.length == 0);
             }
 
+            fillDataSource(signOnly && !mReturnResult);
+            fillDataDestination();
+
             // streams
             in = mDataSource.getInputData(this, true);
             out = mDataDestination.getOutputStream(this);
@@ -661,14 +663,18 @@ public class EncryptActivity extends BaseActivity {
             if (signOnly) {
                 Apg.signText(this, in, out, getSecretKeyId(),
                              Apg.getCachedPassPhrase(getSecretKeyId()),
-                             mPreferences.getDefaultHashAlgorithm(), this);
+                             mPreferences.getDefaultHashAlgorithm(),
+                             mPreferences.getForceV3Signatures(),
+                             this);
             } else {
                 Apg.encrypt(this, in, out, useAsciiArmour,
                             encryptionKeyIds, signatureKeyId,
                             Apg.getCachedPassPhrase(signatureKeyId), this,
                             mPreferences.getDefaultEncryptionAlgorithm(),
                             mPreferences.getDefaultHashAlgorithm(),
-                            compressionId, passPhrase);
+                            compressionId,
+                            mPreferences.getForceV3Signatures(),
+                            passPhrase);
             }
 
             out.close();
@@ -930,7 +936,7 @@ public class EncryptActivity extends BaseActivity {
         return super.onCreateDialog(id);
     }
 
-    protected void fillDataSource() {
+    protected void fillDataSource(boolean fixContent) {
         mDataSource = new DataSource();
         if (mContentUri != null) {
             mDataSource.setUri(mContentUri);
@@ -940,7 +946,19 @@ public class EncryptActivity extends BaseActivity {
             if (mData != null) {
                 mDataSource.setData(mData);
             } else {
-                mDataSource.setText(mMessage.getText().toString());
+                String message = mMessage.getText().toString();
+                if (fixContent) {
+                    // fix the message a bit, trailing spaces and newlines break stuff,
+                    // because GMail sends as HTML and such things fuck up the
+                    // signature,
+                    // TODO: things like "<" and ">" also fuck up the signature
+                    message = message.replaceAll(" +\n", "\n");
+                    message = message.replaceAll("\n\n+", "\n\n");
+                    message = message.replaceFirst("^\n+", "");
+                    // make sure there'll be exactly one newline at the end
+                    message = message.replaceFirst("\n*$", "\n");
+                }
+                mDataSource.setText(message);
             }
         }
     }

src/org/thialfihar/android/apg/Preferences.java

@@ -103,6 +103,16 @@ public class Preferences {
         editor.commit();
     }
 
+    public boolean getForceV3Signatures() {
+        return mSharedPreferences.getBoolean(Constants.pref.force_v3_signatures, false);
+    }
+
+    public void setForceV3Signatures(boolean value) {
+        SharedPreferences.Editor editor = mSharedPreferences.edit();
+        editor.putBoolean(Constants.pref.force_v3_signatures, value);
+        editor.commit();
+    }
+
     public boolean hasSeenChangeLog(String version) {
         return mSharedPreferences.getBoolean(Constants.pref.has_seen_change_log + version,
                                        false);

src/org/thialfihar/android/apg/PreferencesActivity.java

@@ -37,6 +37,7 @@ public class PreferencesActivity extends PreferenceActivity {
     private IntegerListPreference mMessageCompression = null;
     private IntegerListPreference mFileCompression = null;
     private CheckBoxPreference mAsciiArmour = null;
+    private CheckBoxPreference mForceV3Signatures = null;
     private Preferences mPreferences;
 
     @Override
@@ -210,6 +211,18 @@ public class PreferencesActivity extends PreferenceActivity {
                 return false;
             }
         });
+
+        mForceV3Signatures = (CheckBoxPreference) findPreference(Constants.pref.force_v3_signatures);
+        mForceV3Signatures.setChecked(mPreferences.getForceV3Signatures());
+        mForceV3Signatures.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener()
+        {
+            public boolean onPreferenceChange(Preference preference, Object newValue)
+            {
+                mForceV3Signatures.setChecked((Boolean)newValue);
+                mPreferences.setForceV3Signatures((Boolean)newValue);
+                return false;
+            }
+        });
     }
 }