This is the source code for the OTP Authenticator app for Android. https://github.com/kaie/otp-authenticator-android

Android binaries available at: https://kuix.de/android/otp-authenticator/

The OTP Authenticator project includes implementations of one-time passcode generators for the Android platform. One-time passcodes are generated using open standards developed by the Initiative for Open Authentication (OATH) (which is unrelated to OAuth).

This implementation supports the HMAC-Based One-time Password (HOTP) algorithm specified in RFC 4226 and the Time-based One-time Password (TOTP) algorithm specified in RFC 6238.

The app supports:

• Multiple accounts
• Support for 30-second TOTP codes
• Support for counter-based HOTP codes
• Key provisioning via scanning a QR code
• Manual key entry of RFC 3548 base32 key strings

Minimal hints for building:

• install an Android bundle (ADT)
• get jdk 6
• set JAVA_HOME
• add adt/.../sdk/tools and jdk/bin directories to PATH
• install support for API versions 7 and 14
• follow instructions to create a key store, e.g. keytool -genkey -v -keystore kaiengert-release-key.keystore
  -alias kaiengert -keyalg RSA -keysize 2048 -validity 10000
• update build files: android update project --path .
• add keystore information to file local.properties, e.g.: key.store=/home/username/kaiengert-release-key.keystore key.alias=kaiengert
• build: ant release

Disclaimer: This is a fork of Google Authenticator, based on version 2.21, the last version that was available as open source, which has been obtained from https://code.google.com/p/google-authenticator/