Add ConsumerOptions.setIgnoreMDCErrors()

This method can be used to make PGPainless ignore certain MDC related errors or mishabits.
Use of this options is discouraged, but may come in handy in some situations.

Fixes #190

pgpainless-core/src/test/java/org/pgpainless/decryption_verification/ModificationDetectionTests.java

@@ -124,6 +124,96 @@ public class ModificationDetectionTests {
             "=miES\n" +
             "-----END PGP PRIVATE KEY BLOCK-----\n";
 
+    private static final String MESSAGE_TAMPERED_CIPHERTEXT = "-----BEGIN PGP MESSAGE-----\n" +
+            "\n" +
+            "wcDMA3wvqk35PDeyAQv+NgaEl1h8ZLRD0YiGFqVyO4G0slWQotmgPuovBU8YpNPd\n" +
+            "A/sROQAOpkxR0mSzhUpMcgkpwi1r7dC3HGQCf+mitGwe+JFXCTx7N/4t1U321BKj\n" +
+            "c7k7Zu9pDHpPzWi52T6yL30dyR7XkU85P2BrZoOc7B6GuZF07f4qIG1c3+YzBWuw\n" +
+            "cXyqAmLx/zHUkX72Ga6vzUX/ud08gGYeWthLim7jLG9JzNr+BGnOb93+bKTwe7GX\n" +
+            "dxNkBP7NTtGaFBM9epvsBiMSBIUHxuJDFgN4KSzpTP3+tcgrpTAaNWalJPzzphqD\n" +
+            "Iu7ZrBDARQb/8FIymHt0QITZXu3ml8WopiIDbC42JOt16aMy5VDbcP/LlVZn/DB7\n" +
+            "xr3waDZoxIMhNDcnu8R0w25pbf9T6Lt90a8/UIewCVjciUF82TK6KWLJkTJhmRK3\n" +
+            "QJ/XgkMhDhS94Rj+l+FIRxJF/oyTtRFoeBHOB8V5neqXmOgGf3aX5UIJu3pf+GH/\n" +
+            "n+PEoyEw7S7gQxF4VV4S0kwBZlc6xwHfvO+NPf7W0rAtUxMdOl3LBLiILDxF+cq2\n" +
+            "eKG76gkewCp4EhTfK+iDr4KlObXDzADm1cXRlqFhtoQZrHV0poZVw2kIwSlF\n" +
+            "=3G7i\n" +
+            "-----END PGP MESSAGE-----\n";
+
+    private static final String MESSAGE_MISSING_MDC = "-----BEGIN PGP MESSAGE-----\n" +
+            "\n" +
+            "wcDMA3wvqk35PDeyAQwAnTmchA6ve/aF7cPEnyJSb9Ot61LSIMrU3+RaEdA90qn4\n" +
+            "iC+yA7rH+nBX4t9nYSLI4EbQibSfzgxj0Bon1sAwfUfU88UMHypnL1HYsZRoiiLe\n" +
+            "crRr/9Vot2X1firhSu6kwqPZw5eIbvPPhHojZxWo7Plv7lDsXdtgRXc544jKA+Cx\n" +
+            "4Rt9D0WG7sWDifHUaitNHC4klZbvO29qmaND1F+RNUpO6H1j63UCPvHqSEvfV+kT\n" +
+            "vQXtOqk34SLo8SOfpni8Dy1wUePIbuaXyqe5uwSprWoAAmRZOjskv6z28pj9jVs3\n" +
+            "dWRkWca5Mmm3VQZlmxcNeFyTAgSth0GNalwWSVNcPK9W/VaDX8ecw7xYU04cpbQr\n" +
+            "a4JF9oc33bhgn4ZDdcvcP8/QUQP+TyN4vGjp1k9+AgkIsJjLanqHE29chsh7ZcVF\n" +
+            "GDjq3DppEo/Hh647rYRqXpxLfJB6fsDyYLmqNKsBcgtBqE9DtiXQ16GuGFrePxd2\n" +
+            "nRKcSWQbisEa1LHr8G4d0jYBMjIoPiEhw4sgEt1ZCiQPO1HXqaK7VN3PhPOqjyjf\n" +
+            "Rt6lN5kVA3+Dd2DRov9NQ83TQPJdg7I=\n" +
+            "=pgX9\n" +
+            "-----END PGP MESSAGE-----\n";
+
+    private static final String MESSAGE_TAMPERED_MDC = "-----BEGIN PGP MESSAGE-----\n" +
+            "\n" +
+            "wcDMA3wvqk35PDeyAQv+NgaEl1h8ZLRD0YiGFqVyO4G0slWQotmgPuovBU8YpNPd\n" +
+            "A/sROQAOpkxR0mSzhUpMcgkpwi1r7dC3HGQCf+mitGwe+JFXCTx7N/4t1U321BKj\n" +
+            "c7k7Zu9pDHpPzWi52T6yL30dyR7XkU85P2BrZoOc7B6GuZF07f4qIG1c3+YzBWuw\n" +
+            "cXyqAmLx/zHUkX72Ga6vzUX/ud08gGYeWthLim7jLG9JzNr+BGnOb93+bKTwe7GX\n" +
+            "dxNkBP7NTtGaFBM9epvsBiMSBIUHxuJDFgN4KSzpTP3+tcgrpTAaNWalJPzzphqD\n" +
+            "Iu7ZrBDARQb/8FIymHt0QITZXu3ml8WopiIDbC42JOt16aMy5VDbcP/LlVZn/DB7\n" +
+            "xr3waDZoxIMhNDcnu8R0w25pbf9T6Lt90a8/UIewCVjciUF82TK6KWLJkTJhmRK3\n" +
+            "QJ/XgkMhDhS94Rj+l+FIRxJF/oyTtRFoeBHOB8V5neqXmOgGf3aX5UIJu3pf+GH/\n" +
+            "n+PEoyEw7S7gQxF4VV4S0kwBZlc6xwHfvO+NPf7W0rAtUxMdOl3LBLiILDxF+cq2\n" +
+            "eKG76gkewCp4EhTfK+iDr4KlObXDzB/m1cXRlqFhtoQZrHV0poZVw2kIwSkA\n" +
+            "=Ishh\n" +
+            "-----END PGP MESSAGE-----\n";
+
+    private static final String MESSAGE_TRUNCATED_MDC = "-----BEGIN PGP MESSAGE-----\n" +
+            "\n" +
+            "wcDMA3wvqk35PDeyAQv+NgaEl1h8ZLRD0YiGFqVyO4G0slWQotmgPuovBU8YpNPd\n" +
+            "A/sROQAOpkxR0mSzhUpMcgkpwi1r7dC3HGQCf+mitGwe+JFXCTx7N/4t1U321BKj\n" +
+            "c7k7Zu9pDHpPzWi52T6yL30dyR7XkU85P2BrZoOc7B6GuZF07f4qIG1c3+YzBWuw\n" +
+            "cXyqAmLx/zHUkX72Ga6vzUX/ud08gGYeWthLim7jLG9JzNr+BGnOb93+bKTwe7GX\n" +
+            "dxNkBP7NTtGaFBM9epvsBiMSBIUHxuJDFgN4KSzpTP3+tcgrpTAaNWalJPzzphqD\n" +
+            "Iu7ZrBDARQb/8FIymHt0QITZXu3ml8WopiIDbC42JOt16aMy5VDbcP/LlVZn/DB7\n" +
+            "xr3waDZoxIMhNDcnu8R0w25pbf9T6Lt90a8/UIewCVjciUF82TK6KWLJkTJhmRK3\n" +
+            "QJ/XgkMhDhS94Rj+l+FIRxJF/oyTtRFoeBHOB8V5neqXmOgGf3aX5UIJu3pf+GH/\n" +
+            "n+PEoyEw7S7gQxF4VV4S0ksBZlc6xwHfvO+NPf7W0rAtUxMdOl3LBLiILDxF+cq2\n" +
+            "eKG76gkewCp4EhTfK+iDr4KlObXDzB/m1cXRlqFhtoQZrHV0poZVw2kIwSk=\n" +
+            "=FDIu\n" +
+            "-----END PGP MESSAGE-----\n";
+
+    private static final String MESSAGE_MDC_WITH_BAD_CTB = "-----BEGIN PGP MESSAGE-----\n" +
+            "\n" +
+            "wcDMA3wvqk35PDeyAQv+NgaEl1h8ZLRD0YiGFqVyO4G0slWQotmgPuovBU8YpNPd\n" +
+            "A/sROQAOpkxR0mSzhUpMcgkpwi1r7dC3HGQCf+mitGwe+JFXCTx7N/4t1U321BKj\n" +
+            "c7k7Zu9pDHpPzWi52T6yL30dyR7XkU85P2BrZoOc7B6GuZF07f4qIG1c3+YzBWuw\n" +
+            "cXyqAmLx/zHUkX72Ga6vzUX/ud08gGYeWthLim7jLG9JzNr+BGnOb93+bKTwe7GX\n" +
+            "dxNkBP7NTtGaFBM9epvsBiMSBIUHxuJDFgN4KSzpTP3+tcgrpTAaNWalJPzzphqD\n" +
+            "Iu7ZrBDARQb/8FIymHt0QITZXu3ml8WopiIDbC42JOt16aMy5VDbcP/LlVZn/DB7\n" +
+            "xr3waDZoxIMhNDcnu8R0w25pbf9T6Lt90a8/UIewCVjciUF82TK6KWLJkTJhmRK3\n" +
+            "QJ/XgkMhDhS94Rj+l+FIRxJF/oyTtRFoeBHOB8V5neqXmOgGf3aX5UIJu3pf+GH/\n" +
+            "n+PEoyEw7S7gQxF4VV4S0kwBZlc6xwHfvO+NPf7W0rAtUxMdOl3LBLiILDxF+cq2\n" +
+            "eKG76gkewCp4EhTfK+iDr4KlObXDzB/n1cXRlqFhtoQZrHV0poZVw2kIwSlF\n" +
+            "=nOqY\n" +
+            "-----END PGP MESSAGE-----\n";
+
+    private static final String MESSAGE_MDC_WITH_BAD_LENGTH = "-----BEGIN PGP MESSAGE-----\n" +
+            "\n" +
+            "wcDMA3wvqk35PDeyAQv+NgaEl1h8ZLRD0YiGFqVyO4G0slWQotmgPuovBU8YpNPd\n" +
+            "A/sROQAOpkxR0mSzhUpMcgkpwi1r7dC3HGQCf+mitGwe+JFXCTx7N/4t1U321BKj\n" +
+            "c7k7Zu9pDHpPzWi52T6yL30dyR7XkU85P2BrZoOc7B6GuZF07f4qIG1c3+YzBWuw\n" +
+            "cXyqAmLx/zHUkX72Ga6vzUX/ud08gGYeWthLim7jLG9JzNr+BGnOb93+bKTwe7GX\n" +
+            "dxNkBP7NTtGaFBM9epvsBiMSBIUHxuJDFgN4KSzpTP3+tcgrpTAaNWalJPzzphqD\n" +
+            "Iu7ZrBDARQb/8FIymHt0QITZXu3ml8WopiIDbC42JOt16aMy5VDbcP/LlVZn/DB7\n" +
+            "xr3waDZoxIMhNDcnu8R0w25pbf9T6Lt90a8/UIewCVjciUF82TK6KWLJkTJhmRK3\n" +
+            "QJ/XgkMhDhS94Rj+l+FIRxJF/oyTtRFoeBHOB8V5neqXmOgGf3aX5UIJu3pf+GH/\n" +
+            "n+PEoyEw7S7gQxF4VV4S0kwBZlc6xwHfvO+NPf7W0rAtUxMdOl3LBLiILDxF+cq2\n" +
+            "eKG76gkewCp4EhTfK+iDr4KlObXDzB/m1MXRlqFhtoQZrHV0poZVw2kIwSlF\n" +
+            "=Ak00\n" +
+            "-----END PGP MESSAGE-----\n";
+
     /**
      * Messages containing a missing MDC shall fail to decrypt.
      * @param implementationFactory implementation factory
@@ -132,26 +222,12 @@ public class ModificationDetectionTests {
      */
     @ParameterizedTest
     @MethodSource("org.pgpainless.util.TestImplementationFactoryProvider#provideImplementationFactories")
-    public void testMissingMDC(ImplementationFactory implementationFactory) throws IOException, PGPException {
+    public void testMissingMDCThrowsByDefault(ImplementationFactory implementationFactory) throws IOException, PGPException {
         ImplementationFactory.setFactoryImplementation(implementationFactory);
-        String message = "-----BEGIN PGP MESSAGE-----\n" +
-                "\n" +
-                "wcDMA3wvqk35PDeyAQwAnTmchA6ve/aF7cPEnyJSb9Ot61LSIMrU3+RaEdA90qn4\n" +
-                "iC+yA7rH+nBX4t9nYSLI4EbQibSfzgxj0Bon1sAwfUfU88UMHypnL1HYsZRoiiLe\n" +
-                "crRr/9Vot2X1firhSu6kwqPZw5eIbvPPhHojZxWo7Plv7lDsXdtgRXc544jKA+Cx\n" +
-                "4Rt9D0WG7sWDifHUaitNHC4klZbvO29qmaND1F+RNUpO6H1j63UCPvHqSEvfV+kT\n" +
-                "vQXtOqk34SLo8SOfpni8Dy1wUePIbuaXyqe5uwSprWoAAmRZOjskv6z28pj9jVs3\n" +
-                "dWRkWca5Mmm3VQZlmxcNeFyTAgSth0GNalwWSVNcPK9W/VaDX8ecw7xYU04cpbQr\n" +
-                "a4JF9oc33bhgn4ZDdcvcP8/QUQP+TyN4vGjp1k9+AgkIsJjLanqHE29chsh7ZcVF\n" +
-                "GDjq3DppEo/Hh647rYRqXpxLfJB6fsDyYLmqNKsBcgtBqE9DtiXQ16GuGFrePxd2\n" +
-                "nRKcSWQbisEa1LHr8G4d0jYBMjIoPiEhw4sgEt1ZCiQPO1HXqaK7VN3PhPOqjyjf\n" +
-                "Rt6lN5kVA3+Dd2DRov9NQ83TQPJdg7I=\n" +
-                "=pgX9\n" +
-                "-----END PGP MESSAGE-----\n";
 
         PGPSecretKeyRingCollection secretKeyRings = getDecryptionKey();
 
-        InputStream in = new ByteArrayInputStream(message.getBytes(StandardCharsets.UTF_8));
+        InputStream in = new ByteArrayInputStream(MESSAGE_MISSING_MDC.getBytes(StandardCharsets.UTF_8));
         DecryptionStream decryptionStream = PGPainless.decryptAndOrVerify()
                 .onInputStream(in)
                 .withOptions(new ConsumerOptions()
@@ -167,24 +243,9 @@ public class ModificationDetectionTests {
 
     @ParameterizedTest
     @MethodSource("org.pgpainless.util.TestImplementationFactoryProvider#provideImplementationFactories")
-    public void tamperedCiphertextTest(ImplementationFactory implementationFactory) throws IOException, PGPException {
+    public void testTamperedCiphertextThrows(ImplementationFactory implementationFactory) throws IOException, PGPException {
         ImplementationFactory.setFactoryImplementation(implementationFactory);
-        String message = "-----BEGIN PGP MESSAGE-----\n" +
-                "\n" +
-                "wcDMA3wvqk35PDeyAQwAnTmchA6ve/aF7cPEnyJSb9Ot61LSIMrU3+RaEdA90qn4\n" +
-                "iC+yA7rH+nBX4t9nYSLI4EbQibSfzgxj0Bon1sAwfUfU88UMHypnL1HYsZRoiiLe\n" +
-                "crRr/9Vot2X1firhSu6kwqPZw5eIbvPPhHojZxWo7Plv7lDsXdtgRXc544jKA+Cx\n" +
-                "4Rt9D0WG7sWDifHUaitNHC4klZbvO29qmaND1F+RNUpO6H1j63UCPvHqSEvfV+kT\n" +
-                "vQXtOqk34SLo8SOfpni8Dy1wUePIbuaXyqe5uwSprWoAAmRZOjskv6z28pj9jVs3\n" +
-                "dWRkWca5Mmm3VQZlmxcNeFyTAgSth0GNalwWSVNcPK9W/VaDX8ecw7xYU04cpbQr\n" +
-                "a4JF9oc33bhgn4ZDdcvcP8/QUQP+TyN4vGjp1k9+AgkIsJjLanqHE29chsh7ZcVF\n" +
-                "GDjq3DppEo/Hh647rYRqXpxLfJB6fsDyYLmqNKsBcgtBqE9DtiXQ16GuGFrePxd2\n" +
-                "nRKcSWQbisEa1LHr8G4d0kwBMjIoPiEhw4sgEt1ZCiQPO1HXqaK7VN3PhPOqjyjf\n" +
-                "Rt6lN5kVA3+Dd2DRov9NQ83TQPJdgwCD5cXqlEliiMR4G0gWh8QZ4oAp541H\n" +
-                "=wx2s\n" +
-                "-----END PGP MESSAGE-----\n";
-
-        ByteArrayInputStream in = new ByteArrayInputStream(message.getBytes(StandardCharsets.UTF_8));
+        ByteArrayInputStream in = new ByteArrayInputStream(MESSAGE_TAMPERED_CIPHERTEXT.getBytes(StandardCharsets.UTF_8));
         DecryptionStream decryptionStream = PGPainless.decryptAndOrVerify()
                 .onInputStream(in)
                 .withOptions(new ConsumerOptions()
@@ -198,24 +259,26 @@ public class ModificationDetectionTests {
 
     @ParameterizedTest
     @MethodSource("org.pgpainless.util.TestImplementationFactoryProvider#provideImplementationFactories")
-    public void tamperedMDCTest(ImplementationFactory implementationFactory) throws IOException, PGPException {
+    public void testIgnoreTamperedCiphertext(ImplementationFactory implementationFactory) throws IOException, PGPException {
         ImplementationFactory.setFactoryImplementation(implementationFactory);
-        String message = "-----BEGIN PGP MESSAGE-----\n" +
-                "\n" +
-                "wcDMA3wvqk35PDeyAQwAnTmchA6ve/aF7cPEnyJSb9Ot61LSIMrU3+RaEdA90qn4\n" +
-                "iC+yA7rH+nBX4t9nYSLI4EbQibSfzgxj0Bon1sAwfUfU88UMHypnL1HYsZRoiiLe\n" +
-                "crRr/9Vot2X1firhSu6kwqPZw5eIbvPPhHojZxWo7Plv7lDsXdtgRXc544jKA+Cx\n" +
-                "4Rt9D0WG7sWDifHUaitNHC4klZbvO29qmaND1F+RNUpO6H1j63UCPvHqSEvfV+kT\n" +
-                "vQXtOqk34SLo8SOfpni8Dy1wUePIbuaXyqe5uwSprWoAAmRZOjskv6z28pj9jVs3\n" +
-                "dWRkWca5Mmm3VQZlmxcNeFyTAgSth0GNalwWSVNcPK9W/VaDX8ecw7xYU04cpbQr\n" +
-                "a4JF9oc33bhgn4ZDdcvcP8/QUQP+TyN4vGjp1k9+AgkIsJjLanqHE29chsh7ZcVF\n" +
-                "GDjq3DppEo/Hh647rYRqXpxLfJB6fsDyYLmqNKsBcgtBqE9DtiXQ16GuGFrePxd2\n" +
-                "nRKcSWQbisEa1LHr8G4d0kwBMjIoPiEhw4sgEt1ZCiQPO1HXqaK7VN3PhPOqjyjf\n" +
-                "Rt6lN5kVA3+Dd2DRov9NQ83TQPJdg7KD5cXqlEliiMR4G0gWh8QZ4oAp540A\n" +
-                "=ucHU\n" +
-                "-----END PGP MESSAGE-----\n";
+        ByteArrayInputStream in = new ByteArrayInputStream(MESSAGE_TAMPERED_CIPHERTEXT.getBytes(StandardCharsets.UTF_8));
+        DecryptionStream decryptionStream = PGPainless.decryptAndOrVerify()
+                .onInputStream(in)
+                .withOptions(new ConsumerOptions()
+                        .addDecryptionKeys(getDecryptionKey(), SecretKeyRingProtector.unprotectedKeys())
+                        .setIgnoreMDCErrors(true)
+                );
 
-        ByteArrayInputStream in = new ByteArrayInputStream(message.getBytes(StandardCharsets.UTF_8));
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        Streams.pipeAll(decryptionStream, out);
+        decryptionStream.close();
+    }
+
+    @ParameterizedTest
+    @MethodSource("org.pgpainless.util.TestImplementationFactoryProvider#provideImplementationFactories")
+    public void testTamperedMDCThrowsByDefault(ImplementationFactory implementationFactory) throws IOException, PGPException {
+        ImplementationFactory.setFactoryImplementation(implementationFactory);
+        ByteArrayInputStream in = new ByteArrayInputStream(MESSAGE_TAMPERED_MDC.getBytes(StandardCharsets.UTF_8));
         DecryptionStream decryptionStream = PGPainless.decryptAndOrVerify()
                 .onInputStream(in)
                 .withOptions(new ConsumerOptions()
@@ -227,6 +290,103 @@ public class ModificationDetectionTests {
         assertThrows(ModificationDetectionException.class, decryptionStream::close);
     }
 
+    @ParameterizedTest
+    @MethodSource("org.pgpainless.util.TestImplementationFactoryProvider#provideImplementationFactories")
+    public void testIgnoreTamperedMDC(ImplementationFactory implementationFactory) throws IOException, PGPException {
+        ImplementationFactory.setFactoryImplementation(implementationFactory);
+        ByteArrayInputStream in = new ByteArrayInputStream(MESSAGE_TAMPERED_MDC.getBytes(StandardCharsets.UTF_8));
+        DecryptionStream decryptionStream = PGPainless.decryptAndOrVerify()
+                .onInputStream(in)
+                .withOptions(new ConsumerOptions()
+                        .addDecryptionKeys(getDecryptionKey(), SecretKeyRingProtector.unprotectedKeys())
+                        .setIgnoreMDCErrors(true)
+                );
+
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        Streams.pipeAll(decryptionStream, out);
+    }
+
+    @ParameterizedTest
+    @MethodSource("org.pgpainless.util.TestImplementationFactoryProvider#provideImplementationFactories")
+    public void testTruncatedMDCThrows(ImplementationFactory implementationFactory) throws IOException, PGPException {
+        ImplementationFactory.setFactoryImplementation(implementationFactory);
+        ByteArrayInputStream in = new ByteArrayInputStream(MESSAGE_TRUNCATED_MDC.getBytes(StandardCharsets.UTF_8));
+        DecryptionStream decryptionStream = PGPainless.decryptAndOrVerify()
+                .onInputStream(in)
+                .withOptions(new ConsumerOptions()
+                        .addDecryptionKeys(getDecryptionKey(), SecretKeyRingProtector.unprotectedKeys())
+                );
+
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        assertThrows(EOFException.class, () -> Streams.pipeAll(decryptionStream, out));
+    }
+
+    @ParameterizedTest
+    @MethodSource("org.pgpainless.util.TestImplementationFactoryProvider#provideImplementationFactories")
+    public void testMDCWithBadCTBThrows(ImplementationFactory implementationFactory) throws IOException, PGPException {
+        ImplementationFactory.setFactoryImplementation(implementationFactory);
+        ByteArrayInputStream in = new ByteArrayInputStream(MESSAGE_MDC_WITH_BAD_CTB.getBytes(StandardCharsets.UTF_8));
+        DecryptionStream decryptionStream = PGPainless.decryptAndOrVerify()
+                .onInputStream(in)
+                .withOptions(new ConsumerOptions()
+                        .addDecryptionKeys(getDecryptionKey(), SecretKeyRingProtector.unprotectedKeys())
+                );
+
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        Streams.pipeAll(decryptionStream, out);
+        assertThrows(ModificationDetectionException.class, decryptionStream::close);
+    }
+
+    @ParameterizedTest
+    @MethodSource("org.pgpainless.util.TestImplementationFactoryProvider#provideImplementationFactories")
+    public void testIgnoreMDCWithBadCTB(ImplementationFactory implementationFactory) throws IOException, PGPException {
+        ImplementationFactory.setFactoryImplementation(implementationFactory);
+        ByteArrayInputStream in = new ByteArrayInputStream(MESSAGE_MDC_WITH_BAD_CTB.getBytes(StandardCharsets.UTF_8));
+        DecryptionStream decryptionStream = PGPainless.decryptAndOrVerify()
+                .onInputStream(in)
+                .withOptions(new ConsumerOptions()
+                        .addDecryptionKeys(getDecryptionKey(), SecretKeyRingProtector.unprotectedKeys())
+                        .setIgnoreMDCErrors(true)
+                );
+
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        Streams.pipeAll(decryptionStream, out);
+        decryptionStream.close();
+    }
+
+    @ParameterizedTest
+    @MethodSource("org.pgpainless.util.TestImplementationFactoryProvider#provideImplementationFactories")
+    public void testMDCWithBadLengthThrows(ImplementationFactory implementationFactory) throws IOException, PGPException {
+        ImplementationFactory.setFactoryImplementation(implementationFactory);
+        ByteArrayInputStream in = new ByteArrayInputStream(MESSAGE_MDC_WITH_BAD_LENGTH.getBytes(StandardCharsets.UTF_8));
+        DecryptionStream decryptionStream = PGPainless.decryptAndOrVerify()
+                .onInputStream(in)
+                .withOptions(new ConsumerOptions()
+                        .addDecryptionKeys(getDecryptionKey(), SecretKeyRingProtector.unprotectedKeys())
+                );
+
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        Streams.pipeAll(decryptionStream, out);
+        assertThrows(ModificationDetectionException.class, decryptionStream::close);
+    }
+
+    @ParameterizedTest
+    @MethodSource("org.pgpainless.util.TestImplementationFactoryProvider#provideImplementationFactories")
+    public void testIgnoreMDCWithBadLength(ImplementationFactory implementationFactory) throws IOException, PGPException {
+        ImplementationFactory.setFactoryImplementation(implementationFactory);
+        ByteArrayInputStream in = new ByteArrayInputStream(MESSAGE_MDC_WITH_BAD_LENGTH.getBytes(StandardCharsets.UTF_8));
+        DecryptionStream decryptionStream = PGPainless.decryptAndOrVerify()
+                .onInputStream(in)
+                .withOptions(new ConsumerOptions()
+                        .addDecryptionKeys(getDecryptionKey(), SecretKeyRingProtector.unprotectedKeys())
+                        .setIgnoreMDCErrors(true)
+                );
+
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        Streams.pipeAll(decryptionStream, out);
+        decryptionStream.close();
+    }
+
     @Test
     public void decryptMessageWithSEDPacket() throws IOException, PGPException {
         Passphrase passphrase = Passphrase.fromPassword("flowcrypt compatibility tests");