diff --git a/pgpainless-core/src/main/java/org/pgpainless/util/selection/userid/SelectUserId.java b/pgpainless-core/src/main/java/org/pgpainless/util/selection/userid/SelectUserId.java
index 4cf5f76b..50dbb6d9 100644
--- a/pgpainless-core/src/main/java/org/pgpainless/util/selection/userid/SelectUserId.java
+++ b/pgpainless-core/src/main/java/org/pgpainless/util/selection/userid/SelectUserId.java
@@ -118,4 +118,13 @@ public abstract class SelectUserId {
             }
         };
     }
+
+    public static SelectUserId not(SelectUserId strategy) {
+        return new SelectUserId() {
+            @Override
+            protected boolean accept(String userId) {
+                return !strategy.accept(userId);
+            }
+        };
+    }
 }
diff --git a/pgpainless-core/src/test/java/org/pgpainless/util/selection/userid/SelectUserIdTest.java b/pgpainless-core/src/test/java/org/pgpainless/util/selection/userid/SelectUserIdTest.java
new file mode 100644
index 00000000..ce5770ea
--- /dev/null
+++ b/pgpainless-core/src/test/java/org/pgpainless/util/selection/userid/SelectUserIdTest.java
@@ -0,0 +1,124 @@
+/*
+ * Copyright 2021 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.util.selection.userid;
+
+import org.bouncycastle.openpgp.PGPException;
+import org.bouncycastle.openpgp.PGPSecretKeyRing;
+import org.junit.jupiter.api.Test;
+import org.pgpainless.PGPainless;
+import org.pgpainless.key.protection.SecretKeyRingProtector;
+import org.pgpainless.key.util.UserId;
+
+import java.security.InvalidAlgorithmParameterException;
+import java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+public class SelectUserIdTest {
+
+    @Test
+    public void test() throws InvalidAlgorithmParameterException, NoSuchAlgorithmException, PGPException {
+        PGPSecretKeyRing secretKeys = PGPainless.generateKeyRing()
+                .simpleEcKeyRing("<alice@wonderland.lit>");
+        secretKeys = PGPainless.modifyKeyRing(secretKeys)
+                .addUserId(
+                        UserId.withName("Alice Liddell").noComment().withEmail("crazy@the-rabbit.hole"),
+                        SecretKeyRingProtector.unprotectedKeys())
+                .done();
+
+        List<String> validEmail = SelectUserId.and(
+                SelectUserId.validUserId(secretKeys),
+                SelectUserId.containsEmailAddress("alice@wonderland.lit")
+        ).selectUserIds(secretKeys);
+
+        assertEquals(Collections.singletonList("<alice@wonderland.lit>"), validEmail);
+
+        List<String> startsWithAlice = SelectUserId.startsWith("Alice").selectUserIds(secretKeys);
+        assertEquals(Collections.singletonList("Alice Liddell <crazy@the-rabbit.hole>"), startsWithAlice);
+
+        List<String> exactMatch = SelectUserId.or(
+                SelectUserId.exactMatch("<alice@wonderland.lit>"),
+                SelectUserId.startsWith("Not Found")
+        ).selectUserIds(secretKeys);
+        assertEquals(Collections.singletonList("<alice@wonderland.lit>"), exactMatch);
+    }
+
+    @Test
+    public void testContainsSubstring() throws InvalidAlgorithmParameterException, NoSuchAlgorithmException, PGPException {
+        PGPSecretKeyRing secretKeys = PGPainless.generateKeyRing().simpleEcKeyRing("wine drinker");
+        secretKeys = PGPainless.modifyKeyRing(secretKeys)
+                .addUserId("this is not a quine", SecretKeyRingProtector.unprotectedKeys())
+                .addUserId("this is not a crime", SecretKeyRingProtector.unprotectedKeys())
+                .done();
+
+        List<String> containSubstring = SelectUserId.containsSubstring("ine")
+                .selectUserIds(secretKeys);
+        assertEquals(Arrays.asList("wine drinker", "this is not a quine"), containSubstring);
+    }
+
+    @Test
+    public void testContainsEmailAddress() throws InvalidAlgorithmParameterException, NoSuchAlgorithmException, PGPException {
+        PGPSecretKeyRing secretKeys = PGPainless.generateKeyRing().simpleEcKeyRing("Alice <alice@wonderland.lit>");
+
+        assertEquals("Alice <alice@wonderland.lit>", SelectUserId.containsEmailAddress("alice@wonderland.lit").firstMatch(secretKeys));
+        assertEquals("Alice <alice@wonderland.lit>", SelectUserId.containsEmailAddress("<alice@wonderland.lit>").firstMatch(secretKeys));
+
+        assertNull(SelectUserId.containsEmailAddress("mad@hatter.lit").firstMatch(secretKeys));
+    }
+
+    @Test
+    public void testAndOrNot() throws InvalidAlgorithmParameterException, NoSuchAlgorithmException, PGPException {
+        PGPSecretKeyRing secretKeys = PGPainless.generateKeyRing().simpleEcKeyRing("Alice <alice@wonderland.lit>");
+        secretKeys = PGPainless.modifyKeyRing(secretKeys)
+                .addUserId("Alice <another@email.address>", SecretKeyRingProtector.unprotectedKeys())
+                .addUserId("<crazy@the-rabbit.hole>", SecretKeyRingProtector.unprotectedKeys())
+                .addUserId("Crazy Girl <alice@wonderland.lit>", SecretKeyRingProtector.unprotectedKeys())
+                .done();
+
+        List<String> or = SelectUserId.or(
+                SelectUserId.containsEmailAddress("alice@wonderland.lit"),
+                SelectUserId.startsWith("Alice"))
+                .selectUserIds(secretKeys);
+        assertEquals(Arrays.asList("Alice <alice@wonderland.lit>", "Alice <another@email.address>", "Crazy Girl <alice@wonderland.lit>"), or);
+
+        List<String> and = SelectUserId.and(
+                SelectUserId.containsEmailAddress("alice@wonderland.lit"),
+                SelectUserId.startsWith("Alice"))
+                .selectUserIds(secretKeys);
+        assertEquals(Collections.singletonList("Alice <alice@wonderland.lit>"), and);
+
+        List<String> not = SelectUserId.not(
+                SelectUserId.startsWith("Alice"))
+                .selectUserIds(secretKeys);
+        assertEquals(Arrays.asList("<crazy@the-rabbit.hole>", "Crazy Girl <alice@wonderland.lit>"), not);
+    }
+
+    @Test
+    public void testFirstMatch() throws InvalidAlgorithmParameterException, NoSuchAlgorithmException, PGPException {
+        PGPSecretKeyRing secretKeys = PGPainless.generateKeyRing().simpleEcKeyRing("First UserID");
+        secretKeys = PGPainless.modifyKeyRing(secretKeys)
+                .addUserId("Second UserID", SecretKeyRingProtector.unprotectedKeys())
+                .done();
+        assertEquals("First UserID", SelectUserId.validUserId(secretKeys).firstMatch(secretKeys));
+        assertEquals("Second UserID", SelectUserId.containsSubstring("Second").firstMatch(
+                PGPainless.inspectKeyRing(secretKeys).getUserIds()
+        ));
+    }
+}