Stash

Stash is a Java library that provides capabilities to properly store secrets in memory.

Usage

A Stash instance must be created to manage Secret instances.

Stash stash = Stash.builder()
    .build();

Stash objects provide methods to create a new secret with a given configuration. This configuration is contained in a SecretSpec.

SecretSpec<...> spec = ...;
Secret<...> secret = stash.put(spec, ...);

By default, a secret is put into a storage implementation that protects the secret's sensitive data. Thus, to access a secret's data, a lock must be acquired.

try (Secret<...>.Lock lock = secret.acquire()) {
    // use the lock to modify or query the secrets data 
}

Locks may be released to indicate that they are no longer valid. Once the last lock is released, the secret is put into storage again.

To learn more about this library, please refer to the JavaDoc.

Security

Stash aims to improve the security of sensitive data in memory by reducing the amount of time the data is kept readable in memory. To expose full control to library users, the lock mechanism is used to read data from and write to storage deterministically.

Storage Implementations

In compatible Windows environments, the DPAPI is used to encrypt sensitive data in memory (see CryptProtectMemory). The DPAPI stores the key to encrypt the memory in a secure, non-swappable memory region managed by the OS itself.

When the DPAPI is not available, Stash encrypts the sensitive data using ChaCha20. This storage is available on all platforms, but not as secure as, for example, the DPAPI storage, since the key is stored in insecure memory.

Building from source

Setup

This project uses Gradle's toolchain support to detect and select the JDKs required to run the build. Please refer to the build scripts to find out which toolchains are requested.

An installed JDK 1.8 (or later) is required to use Gradle.

Building

Once the setup is complete, invoke the respective Gradle tasks using the following command on Unix/macOS:

./gradlew <tasks>

or the following command on Windows:

gradlew <tasks>

Important Gradle tasks to remember are:

• clean - clean build results
• build - assemble and test the Java library
• publishToMavenLocal - build and install all public artifacts to the local maven repository

Additionally tasks may be used to print a list of all available tasks.

License

Copyright (c) 2022 Leon Linhart

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.