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This is the source code for the OTP Authenticator app for Android.

Android binaries available at:

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, e.g.: 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