diff --git a/pgpainless-core/src/main/java/org/pgpainless/encryption_signing/EncryptionOptions.java b/pgpainless-core/src/main/java/org/pgpainless/encryption_signing/EncryptionOptions.java
index 7c8542a3..5d08ba65 100644
--- a/pgpainless-core/src/main/java/org/pgpainless/encryption_signing/EncryptionOptions.java
+++ b/pgpainless-core/src/main/java/org/pgpainless/encryption_signing/EncryptionOptions.java
@@ -146,7 +146,7 @@ public class EncryptionOptions {
         List<PGPPublicKey> encryptionSubkeys = encryptionKeySelectionStrategy
                 .selectEncryptionSubkeys(info.getEncryptionSubkeys(userId, purpose));
         if (encryptionSubkeys.isEmpty()) {
-            throw new AssertionError("Key has no suitable encryption subkeys.");
+            throw new IllegalArgumentException("Key has no suitable encryption subkeys.");
         }
 
         for (PGPPublicKey encryptionSubkey : encryptionSubkeys) {