TOTP: Time-Based One-Time Password Algorithm
RFC 6238
Document | Type |
RFC - Informational
(May 2011; Errata)
Was draft-mraihi-totp-timebased (individual in sec area)
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Authors | Mountain View , Johan Rydell , Mingliang Pei , Salah Machani | ||
Last updated | 2020-01-21 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized with errata bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 6238 (Informational) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Sean Turner | ||
IESG note | Hannes Tschofenig (Hannes.Tschofenig@gmx.net) is the document shepherd. | ||
Send notices to | Hannes.Tschofenig@gmx.net |
Internet Engineering Task Force (IETF) D. M'Raihi Request for Comments: 6238 Verisign, Inc. Category: Informational S. Machani ISSN: 2070-1721 Diversinet Corp. M. Pei Symantec J. Rydell Portwise, Inc. May 2011 TOTP: Time-Based One-Time Password Algorithm Abstract This document describes an extension of the One-Time Password (OTP) algorithm, namely the HMAC-based One-Time Password (HOTP) algorithm, as defined in RFC 4226, to support the time-based moving factor. The HOTP algorithm specifies an event-based OTP algorithm, where the moving factor is an event counter. The present work bases the moving factor on a time value. A time-based variant of the OTP algorithm provides short-lived OTP values, which are desirable for enhanced security. The proposed algorithm can be used across a wide range of network applications, from remote Virtual Private Network (VPN) access and Wi-Fi network logon to transaction-oriented Web applications. The authors believe that a common and shared algorithm will facilitate adoption of two-factor authentication on the Internet by enabling interoperability across commercial and open-source implementations. Status of This Memo This document is not an Internet Standards Track specification; it is published for informational purposes. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6238. M'Raihi, et al. Informational [Page 1] RFC 6238 HOTPTimeBased May 2011 Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction ....................................................2 1.1. Scope ......................................................2 1.2. Background .................................................3 2. Notation and Terminology ........................................3 3. Algorithm Requirements ..........................................3 4. TOTP Algorithm ..................................................4 4.1. Notations ..................................................4 4.2. Description ................................................4 5. Security Considerations .........................................5 5.1. General ....................................................5 5.2. Validation and Time-Step Size ..............................6 6. Resynchronization ...............................................7 7. Acknowledgements ................................................7 8. References ......................................................8 8.1. Normative References .......................................8 8.2. Informative References .....................................8 Appendix A. TOTP Algorithm: Reference Implementation ...............9 Appendix B. Test Vectors ..........................................14 1. Introduction 1.1. Scope This document describes an extension of the One-Time Password (OTP) algorithm, namely the HMAC-based One-Time Password (HOTP) algorithm, as defined in [RFC4226], to support the time-based moving factor. M'Raihi, et al. Informational [Page 2] RFC 6238 HOTPTimeBased May 2011 1.2. Background As defined in [RFC4226], the HOTP algorithm is based on theShow full document text