Java

A Java standalone implementation of the bcrypt password hash function. Based on the Blowfish cipher it is the default password hash algorithm for OpenBSD and other systems including some Linux distributions. Includes a CLI Tool.

A convenient pattern to always use interfaces where possible but to keep the code-footprint and complexity of relations small

When starting a new project, all the Proguard configuration goes into that single proguard-rules.pro file. This is fine for the beginning…

What to consider when encrypting your data and how to correctly implement it with AES-GCM.

SLF4J binding for Timber - a logger with a small, extensible API which provides utility on top of Android`s normal Log class.

A shared preference implementation for confidential data in Android. Per default uses AES-GCM, BCrypt and HKDF as cryptographic primitives. Uses the concept of device fingerprinting combined with optional user provided passwords and strong password hashes.

This was originally posted as an answer to the question “Bit shift operations on a byte array in Java” on stackoverflow.com.

Bytes is a utility library that makes it easy to create, parse, transform, validate and convert byte arrays in Java. It supports endianness as well as immutability and mutability, so the caller may decide to favor performance.

This was originally posted as an answer to the question “Is HKDF implemented in Java Cryptography Architecture?” on stackoverflow.com.

A standalone Java 7 implementation of HMAC-based key derivation function (HKDF) defined in RFC 5869 first described by Hugo Krawczyk. HKDF follows the “extract-then-expand” paradigm which is compatible to NIST 800-56C Rev. 1 two step KDF

A cryptographically secure pseudorandom number generator cli tool printing in a wide variety of byte encodings (hex, base64,..) and for many programming languages (c, java, c#, php, etc.) using NIST SP800-90Ar1 HMAC-DRBG. Supports external seeding from various true random services.

This was originally posted as an answer to the question “How to generate a random alpha-numeric string” on stackoverflow.com.

Under the Hood is a flexible and powerful Android debug view library. It uses a modular template system that can be easily extended to your needs, although coming with many useful elements built-in.

A cli tool that helps signing and zip aligning single or multiple Android application packages (APKs) with either debug or provided release certificates. It supports v1, v2 and v3 Android signing scheme has an embedded debug keystore and auto verifies after signing.

A crash recovery library for Android. It allows tracking and handling crashes with different rules for debugging and production.