KeePassJava2

master develop

A Java 8 API for 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 and V4)
• Keepass 2.x Password and Keyfile Credentials
• Read KeePass 1.x 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)

Current Status

The current code is version 2.2.2 - released to Maven September 2024. This is on the main branch. See Build from Source

Key updates relative to 2.1:

• Java 8 (dependencies no longer support Java 7)
• File format version 4 support - with Argon2
• Inclusion of Jackson based KDBX support with a view to removing SimpleXML, JAXB and JAXB support
• Updated keyfile support
• Updated dependencies

See the changelog for more details.

Maven Coordinates

Release

The composite POM for the last release (2.2.2), Java 8 compatible, is

    <groupId>org.linguafranca.pwdb</groupId>
    <artifactId>KeePassJava2</artifactId>
    <version>2.2.2</version>

at Maven Central. Note that the artifactId has become Camel Case from release 2.1.x onwards.

Snapshot

Snapshot builds are erratically available at Sonatype:

    <groupId>org.linguafranca.pwdb</groupId>
    <artifactId>KeePassJava2</artifactId>
    <version>2.2.3-SNAPSHOT</version>

with appropriate <repositories> entry, like:

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

There are also separate POMs for the various modules. The module structure is illustrated below under Build from Source.

Java Version

From release 2.2 it requires Java 1.8. Earlier versions require Java 1.7.

Quick Start

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

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

then choose the Jackson based database implementation, and load the database

  Database database = JacksonDatabase.load(credentials, inputStream)

See below for discussion of other database implementations. Note that they will not be maintained in the future - and see the following regarding making the storage of passwords more secure.

Storing Passwords

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

Available from release 2.2.3 the enhanced Jackson implementation is the only KeePassJava2 database implementation that provides a means of storing passwords other than as String.

Discussion

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, initially KDB, KDBX 3.1 and KDBX 4 (KeePass 2) file formats, subsequently, potentially, others.

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

KeePassJava2 and KeePass

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.

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.xsd documents my understanding of the Keepass XML, and also my lack of understanding, in parts. While preparing release 2.2.3 I found this XSD at the KeePass site. I have not (so far) attempted to reconcile my documentation with it.
3. The following graphic illustrates KDBX 3.1 and 4 file formats:

Database Implementations

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.

There are several other database implementations which will be maintained for bug-fix purposes only, with a view to being withdrawn, since they perform badly and/or depend on obsolete technology.

• SimpleXML - no longer maintained, does not work with Java 17 and up
• JAXB - this causes problems with javax and jakarta namespaces, it's not worth maintaining as it offers no compelling performance or other advantage
• DOM the was the original implementation and validates the fact that DOM based implementations are slow. That said, if you want to load a database and then save it while maintaining whatever quirks existed in the original database then this is the one.

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

Dependencies

Aside from the JRE, at release 2.2, the API depends on:

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

The Jackson implementation depends on:

• Faster XML Jackson

The (historical) Simple XML implementation additionally depends on:

• Simple XML Serialisation Framework (Apache 2 license).
• Faster XML Aalto (Apache 2 license).

For Java 11 and later, Jaxb implementation depends on explicit inclusion no longer provided by JDK of:

• JAXB

It also depends on SLF4J and Junit 4 for tests.

Build from Source

Included POM is for Maven 3.

Module Structure

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
test	test		Shared tests to assess the viability of the implementation.
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	KeePassJava2-kdbx		Provides support for KDBX streaming and security.
jackson	KeePassJava2-jackson		A Jackson based implementation of KDBX. Intended to provide the main support going forward, replacing trhe modules below.
simple	KeePassJava2-simple		A Simple XML Platform implementation of KDBX. Could be useful for Android. Simple cannot be used with Java versions 17 and up.
jaxb	KeePassJava2-jaxb		A JAXB implementation of KDBX. Probably not useful for Android. The generated class bindings might be useful for building other interfaces.
dom	KeePassJava2-dom		A DOM based implementation of KDBX. Being DOM based it is rather slow, but messes less with existing content than the other implementations. Known to work on Android.

Why are there so many implementations for KDBX? Well, the DOM implementation came first, because it can load and save stuff that the implementation doesn't specifically know about. But it is very slow.

Then came the JAXB implementation, but belatedly it seems that Android support is in question. So latterly the Simple implementation. That was probably enough KDBX implementations, however, the Simple XML library seems no longer to be maintained, and along comes the Jackson Implementation.

Jackson is the implementation going forward.

Gradle

If you prefer Gradle the automatic conversion gradle init has been known to convert the POM successfully, however you will need to add something like gradle-source-sets.txt to the build.gradle for the JAXB module, so that the generated sources get compiled correctly.

Change Log

In this file.

Acknowledgements

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.

License

Copyright (c) 2024 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.