diff --git a/src/main/java/org/pgpainless/pgpainless/KeyFilter.java b/src/main/java/org/pgpainless/pgpainless/KeyFilter.java
deleted file mode 100644
index 54f931f7..00000000
--- a/src/main/java/org/pgpainless/pgpainless/KeyFilter.java
+++ /dev/null
@@ -1,59 +0,0 @@
-/*
- * 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 org.pgpainless.pgpainless;
-
-import java.util.HashSet;
-import java.util.Iterator;
-import java.util.Set;
-
-import org.bouncycastle.openpgp.PGPPublicKey;
-import org.bouncycastle.openpgp.PGPPublicKeyRing;
-import org.bouncycastle.openpgp.PGPPublicKeyRingCollection;
-
-public abstract class KeyFilter {
-
-    public Set<Long> filter(Set<Long> initialIdSet, PGPPublicKeyRingCollection collection) {
-        Set<PGPPublicKeyRing> rings = new HashSet<>();
-        for (Iterator<PGPPublicKeyRing> i = collection.getKeyRings(); i.hasNext();) {
-            rings.add(i.next());
-        }
-        return filter(initialIdSet, rings, false);
-    }
-
-    public Set<Long> filter(Set<Long> initialIdSet, Set<PGPPublicKeyRing> rings, boolean boolToAvoidSameMethodErasure) {
-        Set<PGPPublicKey> keys = new HashSet<>();
-        for (PGPPublicKeyRing ring : rings) {
-            for (Iterator<PGPPublicKey> i = ring.getPublicKeys(); i.hasNext();) {
-                keys.add(i.next());
-            }
-        }
-        return filter(initialIdSet, keys);
-    }
-
-    public Set<Long> filter(Set<Long> initialIdSet, Set<PGPPublicKey> keys) {
-        Set<Long> filteredIds = new HashSet<>();
-        for (Long id : initialIdSet) {
-            for (PGPPublicKey key : keys) {
-                if (key.getKeyID() == id && filter(key)) {
-                    filteredIds.add(id);
-                }
-            }
-        }
-        return filteredIds;
-    }
-
-    public abstract boolean filter(PGPPublicKey key);
-}
diff --git a/src/main/java/org/pgpainless/pgpainless/PGPv4Fingerprint.java b/src/main/java/org/pgpainless/pgpainless/PGPv4Fingerprint.java
deleted file mode 100644
index 246788f7..00000000
--- a/src/main/java/org/pgpainless/pgpainless/PGPv4Fingerprint.java
+++ /dev/null
@@ -1,55 +0,0 @@
-/*
- * 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 org.pgpainless.pgpainless;
-
-import java.util.Arrays;
-
-import org.bouncycastle.openpgp.PGPPublicKey;
-import org.bouncycastle.openpgp.PGPSecretKey;
-
-public class PGPv4Fingerprint {
-
-    private final byte[] fingerprintBytes;
-
-    public PGPv4Fingerprint(PGPPublicKey publicKey) {
-        if (publicKey.getVersion() != 4) {
-            throw new IllegalArgumentException("PublicKey is not a OpenPGP v4 Public Key.");
-        }
-        this.fingerprintBytes = publicKey.getFingerprint();
-    }
-
-    public PGPv4Fingerprint(PGPSecretKey secretKey) {
-        this(secretKey.getPublicKey());
-    }
-
-    @Override
-    public boolean equals(Object o) {
-        if (o == null) {
-            return false;
-        }
-
-        if (!(o instanceof PGPv4Fingerprint)) {
-            return false;
-        }
-
-        return Arrays.equals(fingerprintBytes, ((PGPv4Fingerprint) o).fingerprintBytes);
-    }
-
-    @Override
-    public int hashCode() {
-        return Arrays.hashCode(fingerprintBytes);
-    }
-}
diff --git a/src/main/java/org/pgpainless/pgpainless/PainlessStream.java b/src/main/java/org/pgpainless/pgpainless/PainlessStream.java
deleted file mode 100644
index 8773570c..00000000
--- a/src/main/java/org/pgpainless/pgpainless/PainlessStream.java
+++ /dev/null
@@ -1,77 +0,0 @@
-/*
- * 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 org.pgpainless.pgpainless;
-
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
-
-public interface PainlessStream {
-
-    boolean isClosed();
-
-    class In extends InputStream implements PainlessStream {
-        private final InputStream inputStream;
-
-        private boolean isClosed = false;
-
-        public In(InputStream inputStream) {
-            this.inputStream = inputStream;
-        }
-
-        @Override
-        public int read() throws IOException {
-            return inputStream.read();
-        }
-
-        @Override
-        public void close() throws IOException {
-            inputStream.close();
-            isClosed = true;
-        }
-
-        @Override
-        public boolean isClosed() {
-            return isClosed;
-        }
-    }
-
-    class Out extends OutputStream implements PainlessStream {
-
-        private final OutputStream outputStream;
-        private boolean isClosed = false;
-
-        public Out(OutputStream outputStream) {
-            this.outputStream = outputStream;
-        }
-
-        @Override
-        public boolean isClosed() {
-            return isClosed;
-        }
-
-        @Override
-        public void write(int i) throws IOException {
-            outputStream.write(i);
-        }
-
-        @Override
-        public void close() throws IOException {
-            outputStream.close();
-            this.isClosed = true;
-        }
-    }
-}