Open Source Android Authentication Apps

Aegis Authenticator is a free and open-source two-factor authentication (2FA) app for Android that helps users secure their online accounts by generating cryptographic one-time passwords (OTPs) such as TOTP and HOTP codes. Unlike many proprietary MFA apps, Aegis is designed with user privacy and local control in mind, storing secrets only on the device in an encrypted vault protected by PIN or biometric unlock, and offering features like backups encrypted with a user-chosen passphrase. It supports importing accounts from QR codes, exporting encrypted backups for safe storage, and grouping or labeling tokens so managing dozens of accounts is simple. Aegis also offers options for custom token configuration, including changing issuer names, digits, and intervals, and includes a robust recovery mechanism in case a device is lost. It has a material design interface that makes navigation intuitive, and its open-source license ensures transparency.

Open source two-factor authentication for Android. It implements Time-based One-time Passwords (TOTP) and HMAC-Based One-Time Passwords (HOTP). Simply scan the QR code and login with the generated 6-digit code. This project started out as a fork of the great OTP Authenticator app written by Bruno Bierbaumer, which has sadly been inactive since 2015. By now almost every aspect of the app has been changed/re-written so the fork status of the Github repository got detached upon user request. But all credit for the original version and for starting this project still goes to Bruno.

AusweisApp is a free, open-source application developed for secure online identification using Germany's electronic identity documents. It enables individuals to authenticate themselves when accessing government services, financial institutions, and other supported online platforms. The software works with German identity cards, electronic residence permits, and eID cards for EU citizens. Users can read their documents through NFC-enabled smartphones or compatible USB card readers. It provides PIN management, document compatibility checks, and encrypted identity verification. Before authentication, the application displays the information requested by the service provider. Available for Windows, macOS, Linux, Android, and iOS, AusweisApp simplifies digital identification while protecting personal information.

Proton Authenticator for Android is Proton’s official Android implementation of a modern two-factor authentication (2FA) app, designed to generate secure, time-based one-time passwords (TOTPs) and support multi-account authentication workflows with strong privacy and encryption features. The app enables users to link 2FA tokens for their online accounts, scan QR codes, and generate rotating verification codes that enhance login security across services that support TOTP standards. Built with native Android tooling and following modern design conventions, it integrates with Android’s notifications and system UI while maintaining local encryption of stored secrets so that authentication tokens are never exposed in plaintext outside the device. It also supports backup and encrypted sync with the associated Proton account, helping users recover 2FA codes across devices — a feature that many standalone token generators lack without risking security trade-offs.

2FAS Auth for Android is the general Android authenticator client for the 2FAS open-source multi-factor authentication suite, designed to help users protect their online accounts with secure, rotating one-time passwords and optionally manage related vault entries. This client lets users add and view TOTP and HOTP tokens for countless services, restore and backup token sets across devices, and secure the app with passcodes or biometrics. The Android implementation emphasizes straightforward setup and usage, providing an incremental list of codes that update in real time, quick token management, and compatibility with common OTP QR codes. It also supports sync and optional integration with 2FAS browser extensions to autofill or streamline authentication workflows when signing in to services across devices.

Yubico Authenticator is an open-source application designed to manage YubiKey security devices and access hardware-protected authentication credentials. It enables users to generate and retrieve one-time passwords stored securely on compatible YubiKeys. The application supports Windows, macOS, Linux, and Android, providing a consistent authentication experience across devices. Users can configure security settings, manage passkeys, and administer authentication credentials through an intuitive interface. It also supports FIDO authentication, PIV certificate management, and YubiKey slot configuration. Sensitive authentication secrets remain on the physical security key rather than being stored directly on the computer or smartphone. With USB and NFC compatibility, the application provides a portable solution for strengthening account security without requiring an internet connection.

A fast, comprehensive, and easy-to-use Java API for communicating with LDAP directory servers and performing related tasks like reading and writing LDIF, encoding and decoding data using base64 and ASN.1 BER, and performing secure communication.

An open source implementation of the FIDO2 protocol to support passwordless strong authentication using public-key cryptography. Supports registration, authentication (all platforms), and transaction authorization (for native Android apps).

The nativescript-fingerprint-auth plugin enables biometric authentication in NativeScript applications, allowing users to authenticate using fingerprint or facial recognition, enhancing security and user convenience.

SikkerBox is a comprehensive security and network utility application designed to provide users with essential security tools and network diagnostics in one convenient package. Key Features Two-Factor Authentication (2FA) Network Diagnostic Tools Port Checker: Verify if specific ports are open or closed on any IP address, provides a list of commonly used ports for quick one-click selection. IP Location Lookup: Determine the geographical location of any IP address, includes the function of automatically obtaining the user’s public IP WiFi Scanner: Analyze nearby WiFi networks, including signal strength, channels, and security information Ping Diagnostic: Test connectivity to domains or IP addresses Whois Lookup: Query registration information for any domain name DNS Reverse Lookup: Find hostnames associated with IP addresses More features：Stay tuned for more features