KeePassJava2

Java 11 API (from version 3.0.0 upwards) for password databases compatible with the renowned KeePass password safe for Windows. This is a "headless" implementation - if you want something with a UI then KeePassXC and KeePassDX could be just the things for you.

Features to date:

• Read and write KeePass 2.x format (KDBX file formats V3.1, V4 and V4.1)
• Keepass 2.x Password and Keyfile Credentials
• Pluggable memory storage and protection strategy
• Read KeePass 1.x format (KDB format, Rijndael only)
• No requirement for JCE Policy Files
• Android compatible
• Interfaces for Database, Group and Entry allow compatible addition of other formats

It is licensed under the Apache 2 License and is currently usable.

The work is provided on an "AS IS" BASIS, WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or
implied, including, without limitation, any warranties
or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY,
or FITNESS FOR A PARTICULAR PURPOSE.

You are solely responsible for determining the appropriateness
of using or redistributing the Work and assume any risks
associated with Your exercise of permissions under this License.

(see license)

This version is 3.0.0-SNAPSHOT. It is the intention that maintenance will cease on version 2 at some point during 2025 once this version is released. Upgrade to V3 requires minor changes to V2 code.

The current released version is version 2.2.4 - released to Maven March 2025. This is on the main branch. See Build from Source

Key updates relative to 2.x

• Java 11
• Pluggable (protected) data storage model
• File format version 4 support - with Argon2
• Removal of SimpleXML, JAXB and JAXB database implementations
• Removed generics on database classes
• Refactor modules and packages
• Updated keyfile support
• Updated dependencies

See the changelog for more details.

For the POM for the last release, see the main branch. As noted, Version 2.x will no longer be maintained once this version is released.

Snapshot builds, such as this version 3.0.0, are available at Sonatype e.g.:

    <groupId>org.linguafranca.pwdb</groupId>
    <artifactId>KeePassJava2</artifactId>
    <version>3.0.0-SNAPSHOT</version>

with appropriate <repositories> entry, like:

  <repositories>
     <repository>
        <id>oss.sonatype.org-snapshot</id>
        <url>https://central.sonatype.com/repository/maven-snapshots/</url>
        <releases>
             <enabled>false</enabled>
        </releases>
        <snapshots>
            <enabled>true</enabled>
        </snapshots>
     </repository>
  </repositories>

The module structure is illustrated below under Build from Source.

Versions 3.0.0 onwards require Java 11. From version 2.2 Java 1.8 is required. Earlier versions require Java 1.7.

Create credentials and an input stream for the password vault in question:

  KdbxCredentials credentials = new KdbxCredentials("123".getBytes());
  InputStream inputStream = getClass().getClassLoader().getResourceAsStream("test1.kdbx");

then load the database:

  Database database = KdbxDatabase.load(credentials, inputStream)

In the past there were a number of different database implementations, at present there are two, one for KDBX (KdbxDatabase - previously called JacksonDatabase, because it uses Jackson for XML serialization) and one to support the KeePass V2 KDB format (KdbDatabase).

There are numerous well-understood problems with storing passwords as Strings in Java. See this discussion about the KeePassJava2 approach to storing passwords.

Password databases are modelled as a three layer abstraction.

A Database is a collection of records whose physical representation needs only to be capable of rendering as a stream. Entries hold the information of value in the database and Groups allow the structuring of entries into collections, just like a folder structure.

The Database has a root group and by following subgroups of the root group the tree structure of the database can be navigated. Entries belong to groups. Entries can be moved between groups and groups can also be moved between groups. However, entries and groups created in one database cannot be moved to another database without being converted:

database.newEntry(entryToCopy);
database.newGroup(groupToCopy);

The class Javadoc on Interface classes Database, Group and Entry describe how to use the methods of those classes to create and modify entries. These classes provide the basis of all implementations of the various database formats, KDBX 3.1, 4 and 4.1 (KeePass 2) as well as KDB (KeePass 1), file formats.

The class QuickStart.java provides some illustrations of operations using the Database, Group and Entry interfaces.

This project is so named by kind permission of Dominik Reichl the author of KeePass. There is no formal connection with that project.

It has always been the intention to support other specific password database implementations. Hence, the creation of abstract Database interfaces rather than following the KeePass model exactly.

KeePass is in effect defined by the code that Dominik writes to create and maintain the project and KDBX File Format Specification describes the file format. There is also a discussion of the differences between KDBX version 3.1 and version 4. Additionally, there is a discussion of the enhancements in KDBX 4.1, as well as a discussion of Key Files. While preparing release 2.2.3 I found this XSD at the KeePass site.

Massive credit also to the folks over at KeePassXC who wrote some documentation about their understanding of various format things. Also, this is a useful discussion/investigation of the KDBX format.

For the sake of clarification and my own satisfaction I have written about my understanding of KeePass formats in the following locations:

1. The Javadoc header to KdbxSerializer describes KDBX stream formatting.
2. The XSD Schema KDBX.4.1.xsd documents my understanding of the Keepass XML, and also my lack of understanding, in parts.
3. The following graphic illustrates KDBX 3.1 and 4 file formats:

KeePass - or more specifically its file format KDBX - is an XML based format, so one of the main tasks is serializing and deserializing XML. Over time (KeePassJava2 was originally released in 2014) approaches to Java and XML have been a bit mysterious. However, Jackson has now been chosen as the underlying framework for implementation of KeePassJava2. From 3.0.0 a single KDBX implementation is available.

Aside from dependencies on underlying frameworks, different implementations have varying characteristics, primarily speed. This is assessed by this test in the module examples.

Aside from the JRE, at release 3.0.0, the API depends on:

• Google Guava (Apache 2 license).
• Apache Commons Codec (Apache 2 license).
• Bouncy Castle (MIT License).
• Jackson XML (Apache 2 license)
• Woodstox (Apache 2 license)

It also depends on SLF4J, logback and Junit 4 for tests.

Included POM is for Maven 3.

There are rather a lot of modules, this is in order to allow loading of minimal necessary functionality. The module dependencies are illustrated below.

Each module corresponds to a Maven artifact. The GroupId is org.linguafranca.pwdb. The version id is as noted above.

Module	ArtifactId	JavaDoc	Description
database	database		Base definition of the Database APIs.
example	example		Worked examples of loading, saving, splicing etc. using the APIs
all	KeePassJava2	(no JavaDoc)	This is the main KeePassJava2 Maven dependency. Provides a route to all artifacts (other than test and examples) via transitive dependency.
kdb	KeePassJava2-kdb		An implementation of the Database APIs supporting KeePass KDB format.
kdbx-io	KeePassJava2-kdbx-io		Provides support for KDBX streaming and security.
kdbx-database	KeePassJava2-kdbx-database		Provides support for KDBX data access and memory protection.
basic	basic		A basic lightweight database implementation. Has memory protection.

If you prefer Gradle the automatic conversion gradle init has been known to convert the POM successfully.

In this file.

Many thanks to Pavel Ivanov @ivanovpv for his help with Android and Gradle compatibility issues back in the very early days.

Thanks to Giuseppe Valente @giusvale-dev for his contribution of the Jackson module and enhancements to KeyFile support.

Thanks to other contributors and raisers of issues.

Copyright (c) 2025 Jo Rabin

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.