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KeePassJava2

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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 (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

After a period of neglect, the project is (May 2023) back in development.

The current code is version 2.2.2. 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 and JAXB support
• Updated keyfile support
• Updated dependencies to remove known vulnerabilities

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 a database implementation, and load the database.

  Database database = SimpleDatabase.load(credentials, inputStream)

or

  Database database = JaxbDatabase.load(credentials, inputStream)

or

  Database database = DomDatabaseWrapper.load(credentials, inputStream)

or

  Database database = JacksonDatabase.load(credentials, inputStream)

Different implementations have varying characteristics, primarily speed. The table below illustrates timings for the file test1.kdbx (in the test module resources - it is around 2k bytes and contains a few dozen entries) as assessed by this test in the "examples" module.

Simple 5 loads 20 iterations 257 millis
Jaxb 5 loads 20 iterations 326 millis
Dom 5 loads 20 iterations 758 millis
Jackson 5 loads 20 iterations 374 millis

Simple 10 loads 1 iterations 340 millis
Jaxb 10 loads 1 iterations 552 millis
Dom 10 loads 1 iterations 175 millis
Jackson 10 loads 1 iterations 343 millis

Simple 1 loads 50 iterations 28 millis
Jaxb 1 loads 50 iterations 47 millis
Dom 1 loads 50 iterations 251 millis
Jackson 1 loads 50 iterations 34 millis

Load time is dominant in this example for JAXB and Simple, database traversal for the DOM implementation.

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. Hence, there is not much by way of definitive specification of KeePass files other than that code. There is a discussion of the differences between KDBX version 3.1 and version 4. There is also 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.

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.
3. The following graphic illustrates KDBX 3.1 and 4 file formats:

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 Simple XML implementation additionally depends on:

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

The Jackson implementation depends on:

• Faster XML Jackson

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.

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.

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.

Thanks to Giuseppe Valente @giusvale-dev for the 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.