diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/results/OperationResult.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/results/OperationResult.java
index 5884dd2d5..9824173f5 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/results/OperationResult.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/results/OperationResult.java
@@ -495,6 +495,8 @@ public abstract class OperationResult implements Parcelable {
         MSG_MF_UID_PRIMARY (LogLevel.INFO, R.string.msg_mf_uid_primary),
         MSG_MF_UID_REVOKE (LogLevel.INFO, R.string.msg_mf_uid_revoke),
         MSG_MF_UID_ERROR_EMPTY (LogLevel.ERROR, R.string.msg_mf_uid_error_empty),
+        MSG_MF_UAT_ADD_IMAGE (LogLevel.INFO, R.string.msg_mf_uat_add_image),
+        MSG_MF_UAT_ADD_UNKNOWN (LogLevel.INFO, R.string.msg_mf_uat_add_unknown),
         MSG_MF_UNLOCK_ERROR (LogLevel.ERROR, R.string.msg_mf_unlock_error),
         MSG_MF_UNLOCK (LogLevel.DEBUG, R.string.msg_mf_unlock),
 
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java
index 128928bb3..8facbfd2a 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java
@@ -34,6 +34,7 @@ import org.spongycastle.openpgp.PGPSecretKeyRing;
 import org.spongycastle.openpgp.PGPSignature;
 import org.spongycastle.openpgp.PGPSignatureGenerator;
 import org.spongycastle.openpgp.PGPSignatureSubpacketGenerator;
+import org.spongycastle.openpgp.PGPUserAttributeSubpacketVector;
 import org.spongycastle.openpgp.operator.PBESecretKeyDecryptor;
 import org.spongycastle.openpgp.operator.PBESecretKeyEncryptor;
 import org.spongycastle.openpgp.operator.PGPContentSignerBuilder;
@@ -478,7 +479,7 @@ public class PgpKeyOperation {
                 PGPPublicKey modifiedPublicKey = masterPublicKey;
 
                 // 2a. Add certificates for new user ids
-                subProgressPush(15, 25);
+                subProgressPush(15, 23);
                 for (int i = 0; i < saveParcel.mAddUserIds.size(); i++) {
 
                     progress(R.string.progress_modify_adduid, (i - 1) * (100 / saveParcel.mAddUserIds.size()));
@@ -522,8 +523,33 @@ public class PgpKeyOperation {
                 }
                 subProgressPop();
 
-                // 2b. Add revocations for revoked user ids
-                subProgressPush(25, 40);
+                // 2b. Add certificates for new user ids
+                subProgressPush(23, 32);
+                for (int i = 0; i < saveParcel.mAddUserAttribute.size(); i++) {
+
+                    progress(R.string.progress_modify_adduat, (i - 1) * (100 / saveParcel.mAddUserAttribute.size()));
+                    WrappedUserAttribute attribute = saveParcel.mAddUserAttribute.get(i);
+
+                    switch (attribute.getType()) {
+                        case WrappedUserAttribute.UAT_UNKNOWN:
+                            log.add(LogType.MSG_MF_UAT_ADD_UNKNOWN, indent);
+                            break;
+                        case WrappedUserAttribute.UAT_IMAGE:
+                            log.add(LogType.MSG_MF_UAT_ADD_IMAGE, indent);
+                            break;
+                    }
+
+                    PGPUserAttributeSubpacketVector vector = attribute.getVector();
+
+                    // generate and add new certificate
+                    PGPSignature cert = generateUserAttributeSignature(masterPrivateKey,
+                            masterPublicKey, vector);
+                    modifiedPublicKey = PGPPublicKey.addCertification(modifiedPublicKey, vector, cert);
+                }
+                subProgressPop();
+
+                // 2c. Add revocations for revoked user ids
+                subProgressPush(32, 40);
                 for (int i = 0; i < saveParcel.mRevokeUserIds.size(); i++) {
 
                     progress(R.string.progress_modify_revokeuid, (i - 1) * (100 / saveParcel.mRevokeUserIds.size()));
@@ -1174,6 +1200,26 @@ public class PgpKeyOperation {
         return sGen.generateCertification(userId, pKey);
     }
 
+    private static PGPSignature generateUserAttributeSignature(
+            PGPPrivateKey masterPrivateKey, PGPPublicKey pKey,
+            PGPUserAttributeSubpacketVector vector)
+                throws IOException, PGPException, SignatureException {
+        PGPContentSignerBuilder signerBuilder = new JcaPGPContentSignerBuilder(
+                masterPrivateKey.getPublicKeyPacket().getAlgorithm(), HashAlgorithmTags.SHA512)
+                .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
+        PGPSignatureGenerator sGen = new PGPSignatureGenerator(signerBuilder);
+
+        PGPSignatureSubpacketGenerator hashedPacketsGen = new PGPSignatureSubpacketGenerator();
+        {
+            /* critical subpackets: we consider those important for a modern pgp implementation */
+            hashedPacketsGen.setSignatureCreationTime(true, new Date());
+        }
+
+        sGen.setHashedSubpackets(hashedPacketsGen.generate());
+        sGen.init(PGPSignature.POSITIVE_CERTIFICATION, masterPrivateKey);
+        return sGen.generateCertification(vector, pKey);
+    }
+
     private static PGPSignature generateRevocationSignature(
             PGPPrivateKey masterPrivateKey, PGPPublicKey pKey, String userId)
         throws IOException, PGPException, SignatureException {
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/SaveKeyringParcel.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/SaveKeyringParcel.java
index 810190fee..a314c8768 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/SaveKeyringParcel.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/SaveKeyringParcel.java
@@ -21,6 +21,7 @@ package org.sufficientlysecure.keychain.service;
 import android.os.Parcel;
 import android.os.Parcelable;
 
+import org.sufficientlysecure.keychain.pgp.WrappedUserAttribute;
 import java.io.Serializable;
 import java.util.ArrayList;
 
@@ -49,6 +50,7 @@ public class SaveKeyringParcel implements Parcelable {
     public ChangeUnlockParcel mNewUnlock;
 
     public ArrayList<String> mAddUserIds;
+    public ArrayList<WrappedUserAttribute> mAddUserAttribute;
     public ArrayList<SubkeyAdd> mAddSubKeys;
 
     public ArrayList<SubkeyChange> mChangeSubKeys;
@@ -71,6 +73,7 @@ public class SaveKeyringParcel implements Parcelable {
     public void reset() {
         mNewUnlock = null;
         mAddUserIds = new ArrayList<String>();
+        mAddUserAttribute = new ArrayList<WrappedUserAttribute>();
         mAddSubKeys = new ArrayList<SubkeyAdd>();
         mChangePrimaryUserId = null;
         mChangeSubKeys = new ArrayList<SubkeyChange>();
@@ -162,6 +165,7 @@ public class SaveKeyringParcel implements Parcelable {
         mNewUnlock = source.readParcelable(getClass().getClassLoader());
 
         mAddUserIds = source.createStringArrayList();
+        mAddUserAttribute = (ArrayList<WrappedUserAttribute>) source.readSerializable();
         mAddSubKeys = (ArrayList<SubkeyAdd>) source.readSerializable();
 
         mChangeSubKeys = (ArrayList<SubkeyChange>) source.readSerializable();
@@ -184,6 +188,7 @@ public class SaveKeyringParcel implements Parcelable {
         destination.writeParcelable(mNewUnlock, 0);
 
         destination.writeStringList(mAddUserIds);
+        destination.writeSerializable(mAddUserAttribute);
         destination.writeSerializable(mAddSubKeys);
 
         destination.writeSerializable(mChangeSubKeys);
@@ -214,6 +219,7 @@ public class SaveKeyringParcel implements Parcelable {
         String out = "mMasterKeyId: " + mMasterKeyId + "\n";
         out += "mNewUnlock: " + mNewUnlock + "\n";
         out += "mAddUserIds: " + mAddUserIds + "\n";
+        out += "mAddUserAttribute: " + mAddUserAttribute + "\n";
         out += "mAddSubKeys: " + mAddSubKeys + "\n";
         out += "mChangeSubKeys: " + mChangeSubKeys + "\n";
         out += "mChangePrimaryUserId: " + mChangePrimaryUserId + "\n";
diff --git a/OpenKeychain/src/main/res/values/strings.xml b/OpenKeychain/src/main/res/values/strings.xml
index 4b5c46a5f..6e2b84642 100644
--- a/OpenKeychain/src/main/res/values/strings.xml
+++ b/OpenKeychain/src/main/res/values/strings.xml
@@ -309,6 +309,7 @@
 
     <string name="progress_modify_unlock">"unlocking keyring…"</string>
     <string name="progress_modify_adduid">"adding user IDs…"</string>
+    <string name="progress_modify_adduat">"adding user attributes…"</string>
     <string name="progress_modify_revokeuid">"revoking user IDs…"</string>
     <string name="progress_modify_primaryuid">"changing primary user ID…"</string>
     <string name="progress_modify_subkeychange">"modifying subkeys…"</string>
@@ -839,6 +840,8 @@
     <string name="msg_mf_uid_primary">"Changing primary user ID to %s"</string>
     <string name="msg_mf_uid_revoke">"Revoking user ID %s"</string>
     <string name="msg_mf_uid_error_empty">"User ID must not be empty!"</string>
+    <string name="msg_mf_uat_add_image">"Adding user attribute of type image"</string>
+    <string name="msg_mf_uat_add_unknown">"Adding user attribute of unknown type"</string>
     <string name="msg_mf_unlock_error">"Error unlocking keyring!"</string>
     <string name="msg_mf_unlock">"Unlocking keyring"</string>