Google Authenticator is a software-based
authenticator
An authenticator is a means used to confirm a user's identity, that is, to perform digital authentication. A person authenticates to a computer system or application by demonstrating that he or she has possession and control of an authenticator. I ...
by
Google
Google LLC (, ) is an American multinational corporation and technology company focusing on online advertising, search engine technology, cloud computing, computer software, quantum computing, e-commerce, consumer electronics, and artificial ...
. It implements
multi-factor authentication
Multi-factor authentication (MFA; two-factor authentication, or 2FA) is an electronic authentication method in which a user is granted access to a website or application only after successfully presenting two or more distinct types of evidence ...
services using the
time-based one-time password
Time-based one-time password (TOTP) is a computer algorithm that generates a one-time password (OTP) using the current time as a source of uniqueness. As an extension of the HMAC-based one-time password (HOTP) algorithm, it has been adopted as In ...
(TOTP; specified in RFC 6238) and
HMAC-based one-time password (HOTP; specified in RFC 4226), for authenticating users of software applications.
When logging into a site supporting Authenticator (including Google services) or using Authenticator-supporting third-party applications such as
password manager
A password manager is a software program to prevent password fatigue by Random password generator, automatically generating, Autofill, autofilling and storing Password, passwords. It can do this for Application software, local applications or web ...
s or
file hosting service
A file-hosting service, also known as cloud-storage service, online file-storage provider, or cyberlocker, is an internet hosting service specifically designed to host user files. These services allow users to upload files that can be accessed o ...
s, Authenticator generates a six- to eight-digit
one-time password
A one-time password (OTP), also known as a one-time PIN, one-time passcode, one-time authorization code (OTAC) or dynamic password, is a password that is valid for only one login session or transaction, on a computer system or other digital dev ...
which users must enter in addition to their usual login details.
Google provides
Android,
Wear OS
Wear OS, formerly Android Wear, is a closed-source Android (operating system), Android distribution designed for smartwatches and other wearable computer, wearable computers, developed by Google. Wear OS is designed to pair with mobile phones run ...
,
BlackBerry
BlackBerry is a discontinued brand of handheld devices and related mobile services, originally developed and maintained by the Canadian company Research In Motion (RIM, later known as BlackBerry Limited) until 2016. The first BlackBerry device ...
, and
iOS
Ios, Io or Nio (, ; ; locally Nios, Νιός) is a Greek island in the Cyclades group in the Aegean Sea. Ios is a hilly island with cliffs down to the sea on most sides. It is situated halfway between Naxos and Santorini. It is about long an ...
versions of Authenticator.
An official
open source
Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use and view the source code, design documents, or content of the product. The open source model is a decentrali ...
fork of the Android app is available on
GitHub
GitHub () is a Proprietary software, proprietary developer platform that allows developers to create, store, manage, and share their code. It uses Git to provide distributed version control and GitHub itself provides access control, bug trackin ...
.
However, this fork was archived in Apr 6, 2021 and is now read only.
Current software releases are