diff --git a/pgpainless-core/src/main/java/org/pgpainless/signature/builder/CertificationSignatureBuilder.java b/pgpainless-core/src/main/java/org/pgpainless/signature/builder/CertificationSignatureBuilder.java
deleted file mode 100644
index e41d9807..00000000
--- a/pgpainless-core/src/main/java/org/pgpainless/signature/builder/CertificationSignatureBuilder.java
+++ /dev/null
@@ -1,76 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package org.pgpainless.signature.builder;
-
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-
-import org.bouncycastle.openpgp.PGPException;
-import org.bouncycastle.openpgp.PGPPublicKey;
-import org.bouncycastle.openpgp.PGPSecretKey;
-import org.bouncycastle.openpgp.PGPSignature;
-import org.bouncycastle.openpgp.PGPUserAttributeSubpacketVector;
-import org.pgpainless.algorithm.SignatureType;
-import org.pgpainless.exception.WrongPassphraseException;
-import org.pgpainless.key.protection.SecretKeyRingProtector;
-import org.pgpainless.signature.subpackets.CertificationSubpackets;
-
-public class CertificationSignatureBuilder extends AbstractSignatureBuilder<CertificationSignatureBuilder> {
-
-    public CertificationSignatureBuilder(PGPSecretKey certificationKey, SecretKeyRingProtector protector)
-            throws WrongPassphraseException {
-        this(SignatureType.GENERIC_CERTIFICATION, certificationKey, protector);
-    }
-
-    public CertificationSignatureBuilder(SignatureType signatureType, PGPSecretKey signingKey, SecretKeyRingProtector protector)
-            throws WrongPassphraseException {
-        super(signatureType, signingKey, protector);
-    }
-
-    public CertificationSignatureBuilder(
-            PGPSecretKey certificationKey,
-            SecretKeyRingProtector protector,
-            PGPSignature archetypeSignature)
-            throws WrongPassphraseException {
-        super(certificationKey, protector, archetypeSignature);
-    }
-
-    public CertificationSubpackets getHashedSubpackets() {
-        return hashedSubpackets;
-    }
-
-    public CertificationSubpackets getUnhashedSubpackets() {
-        return unhashedSubpackets;
-    }
-
-    public void applyCallback(@Nullable CertificationSubpackets.Callback callback) {
-        if (callback != null) {
-            callback.modifyHashedSubpackets(getHashedSubpackets());
-            callback.modifyUnhashedSubpackets(getUnhashedSubpackets());
-        }
-    }
-
-    public PGPSignature build(PGPPublicKey certifiedKey, String userId) throws PGPException {
-        return buildAndInitSignatureGenerator().generateCertification(userId, certifiedKey);
-    }
-
-    public PGPSignature build(PGPPublicKey certifiedKey, PGPUserAttributeSubpacketVector userAttribute)
-            throws PGPException {
-        return buildAndInitSignatureGenerator().generateCertification(userAttribute, certifiedKey);
-    }
-
-    @Override
-    protected boolean isValidSignatureType(@Nonnull SignatureType type) {
-        switch (type) {
-            case GENERIC_CERTIFICATION:
-            case NO_CERTIFICATION:
-            case CASUAL_CERTIFICATION:
-            case POSITIVE_CERTIFICATION:
-                return true;
-            default:
-                return false;
-        }
-    }
-}
diff --git a/pgpainless-core/src/main/java/org/pgpainless/signature/builder/ThirdPartyCertificationSignatureBuilder.java b/pgpainless-core/src/main/java/org/pgpainless/signature/builder/ThirdPartyCertificationSignatureBuilder.java
new file mode 100644
index 00000000..84f9e8dd
--- /dev/null
+++ b/pgpainless-core/src/main/java/org/pgpainless/signature/builder/ThirdPartyCertificationSignatureBuilder.java
@@ -0,0 +1,118 @@
+// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.signature.builder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import org.bouncycastle.openpgp.PGPException;
+import org.bouncycastle.openpgp.PGPPublicKey;
+import org.bouncycastle.openpgp.PGPPublicKeyRing;
+import org.bouncycastle.openpgp.PGPSecretKey;
+import org.bouncycastle.openpgp.PGPSignature;
+import org.bouncycastle.openpgp.PGPUserAttributeSubpacketVector;
+import org.pgpainless.algorithm.SignatureType;
+import org.pgpainless.exception.WrongPassphraseException;
+import org.pgpainless.key.protection.SecretKeyRingProtector;
+import org.pgpainless.signature.subpackets.CertificationSubpackets;
+
+/**
+ * Certification signature builder used to certify other users keys.
+ */
+public class ThirdPartyCertificationSignatureBuilder extends AbstractSignatureBuilder<ThirdPartyCertificationSignatureBuilder> {
+
+    /**
+     * Create a new certification signature builder.
+     * This constructor uses {@link SignatureType#GENERIC_CERTIFICATION} as signature type.
+     *
+     * @param signingKey our own certification key
+     * @param protector protector to unlock the certification key
+     * @throws WrongPassphraseException in case of a wrong passphrase
+     */
+    public ThirdPartyCertificationSignatureBuilder(PGPSecretKey signingKey, SecretKeyRingProtector protector)
+            throws WrongPassphraseException {
+        this(SignatureType.GENERIC_CERTIFICATION, signingKey, protector);
+    }
+
+    /**
+     * Create a new certification signature builder.
+     *
+     * @param signatureType type of certification
+     * @param signingKey our own certification key
+     * @param protector protector to unlock the certification key
+     * @throws WrongPassphraseException in case of a wrong passphrase
+     */
+    public ThirdPartyCertificationSignatureBuilder(SignatureType signatureType, PGPSecretKey signingKey, SecretKeyRingProtector protector)
+            throws WrongPassphraseException {
+        super(signatureType, signingKey, protector);
+    }
+
+    /**
+     * Create a new certification signature builder.
+     *
+     * @param signingKey our own certification key
+     * @param protector protector to unlock the certification key
+     * @param archetypeSignature signature to use as a template for the new signature
+     * @throws WrongPassphraseException in case of a wrong passphrase
+     */
+    public ThirdPartyCertificationSignatureBuilder(
+            PGPSecretKey signingKey,
+            SecretKeyRingProtector protector,
+            PGPSignature archetypeSignature)
+            throws WrongPassphraseException {
+        super(signingKey, protector, archetypeSignature);
+    }
+
+    public CertificationSubpackets getHashedSubpackets() {
+        return hashedSubpackets;
+    }
+
+    public CertificationSubpackets getUnhashedSubpackets() {
+        return unhashedSubpackets;
+    }
+
+    public void applyCallback(@Nullable CertificationSubpackets.Callback callback) {
+        if (callback != null) {
+            callback.modifyHashedSubpackets(getHashedSubpackets());
+            callback.modifyUnhashedSubpackets(getUnhashedSubpackets());
+        }
+    }
+
+    /**
+     * Create a certification signature for the given user-id and the primary key of the given key ring.
+     * @param certifiedKey key ring
+     * @param userId user-id to certify
+     * @return signature
+     * @throws PGPException
+     */
+    public PGPSignature build(PGPPublicKeyRing certifiedKey, String userId) throws PGPException {
+        return buildAndInitSignatureGenerator().generateCertification(userId, certifiedKey.getPublicKey());
+    }
+
+    /**
+     * Create a certification signature for the given user attribute and the primary key of the given key ring.
+     * @param certifiedKey key ring
+     * @param userAttribute user-attributes to certify
+     * @return signature
+     * @throws PGPException
+     */
+    public PGPSignature build(PGPPublicKeyRing certifiedKey, PGPUserAttributeSubpacketVector userAttribute)
+            throws PGPException {
+        return buildAndInitSignatureGenerator().generateCertification(userAttribute, certifiedKey.getPublicKey());
+    }
+
+    @Override
+    protected boolean isValidSignatureType(@Nonnull SignatureType type) {
+        switch (type) {
+            case GENERIC_CERTIFICATION:
+            case NO_CERTIFICATION:
+            case CASUAL_CERTIFICATION:
+            case POSITIVE_CERTIFICATION:
+                return true;
+            default:
+                return false;
+        }
+    }
+}