optionally allow extended key validation in `RecoveryKeyFactory#validateRecoveryKey`

src/main/java/org/cryptomator/ui/recoverykey/RecoveryKeyFactory.java

@@ -7,6 +7,7 @@ import org.cryptomator.cryptolib.api.CryptoException;
 import org.cryptomator.cryptolib.api.InvalidPassphraseException;
 import org.cryptomator.cryptolib.api.Masterkey;
 import org.cryptomator.cryptolib.common.MasterkeyFileAccess;
+import org.jetbrains.annotations.Nullable;
 
 import javax.inject.Inject;
 import javax.inject.Singleton;
@@ -16,6 +17,7 @@ import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.function.Predicate;
 
 import static org.cryptomator.common.Constants.MASTERKEY_BACKUP_SUFFIX;
 import static org.cryptomator.common.Constants.MASTERKEY_FILENAME;
@@ -102,12 +104,29 @@ public class RecoveryKeyFactory {
 	 * @return <code>true</code> if this seems to be a legitimate recovery key
 	 */
 	public boolean validateRecoveryKey(String recoveryKey) {
+		return validateRecoveryKey(recoveryKey, null);
+	}
+
+	/**
+	 * Checks whether a String is a syntactically correct recovery key with a valid checksum and passes the extended validation.
+	 *
+	 * @param recoveryKey A word sequence which might be a recovery key
+	 * @param extendedValidation Additional verification of the decoded key (optional)
+	 * @return <code>true</code> if this seems to be a legitimate recovery key and passes the extended validation
+	 */
+	public boolean validateRecoveryKey(String recoveryKey, @Nullable Predicate<byte[]> extendedValidation) {
+		byte[] key = new byte[0];
 		try {
-			byte[] key = decodeRecoveryKey(recoveryKey);
-			Arrays.fill(key, (byte) 0x00);
-			return true;
+			key = decodeRecoveryKey(recoveryKey);
+			if (extendedValidation != null) {
+				return extendedValidation.test(key);
+			} else {
+				return true;
+			}
 		} catch (IllegalArgumentException e) {
 			return false;
+		} finally {
+			Arrays.fill(key, (byte) 0x00);
 		}
 	}
 

src/test/java/org/cryptomator/ui/recoverykey/RecoveryKeyFactoryTest.java

@@ -7,10 +7,13 @@ import org.cryptomator.cryptolib.common.MasterkeyFileAccess;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 import org.mockito.Mockito;
 
 import java.io.IOException;
 import java.nio.file.Path;
+import java.util.function.Predicate;
 
 public class RecoveryKeyFactoryTest {
 
@@ -75,4 +78,19 @@ public class RecoveryKeyFactoryTest {
 		Assertions.assertTrue(result);
 	}
 
+	@ParameterizedTest(name = "success = {0}")
+	@DisplayName("validateRecoveryKey() with extended validation")
+	@ValueSource(booleans = {true, false})
+	public void testValidateValidateRecoveryKeyWithValidKey(boolean extendedValidationResult) {
+		Predicate<byte[]> validator = Mockito.mock(Predicate.class);
+		Mockito.doReturn(extendedValidationResult).when(validator).test(Mockito.any());
+		boolean result = inTest.validateRecoveryKey("""
+				pathway lift abuse plenty export texture gentleman landscape beyond ceiling around leaf cafe charity \
+				border breakdown victory surely computer cat linger restrict infer crowd live computer true written amazed \
+				investor boot depth left theory snow whereby terminal weekly reject happiness circuit partial cup ad \
+				""", validator);
+		Mockito.verify(validator).test(Mockito.any());
+		Assertions.assertEquals(extendedValidationResult, result);
+	}
+
 }