NAME

Pass::OTP - Perl implementation of HOTP / TOTP algorithms

SYNOPSIS

    use Pass::OTP qw(otp);
    use Pass::OTP::URI qw(parse);
    my $uri = "otpauth://totp/ACME:john.doe@email.com?secret=HXDMVJECJJWSRB3HWIZR4IFUGFTMXBOZ&issuer=ACME&digits=6";
    my $otp_code = otp(parse($uri));

DESCRIPTION

The "Pass::OTP" module provides implementation of HOTP and TOTP algorithms according to the RFC 4226 and RFC 6238.

FUNCTIONS

hotp(%options)

Computes HMAC-based One-time Password (RFC 4226).

    HOTP(K,C) = Truncate(HMAC-SHA-1(K,C))
    

Step 1: Generate an HMAC-SHA-1 value

    Let HS = HMAC-SHA-1(K,C)
    

Step 2: Generate a 4-byte string (Dynamic Truncation)

    Let Sbits = DT(HS)
    

Step 3: Compute an HOTP value

    Let Snum = StToNum(Sbits)       # Convert S to a number in 0..2^{31}-1
    Return D = Snum mod 10^Digit    # D us a number in the range 0..10^{Digit}-1
    

totp(%options)

Computes Time-based One-time Password (RFC 6238).

    TOTP = HOTP(K,T)
    T = (Current Unix time - T0) / X
    

otp(%options)

Convenience wrapper which calls totp/hotp according to options.

SEE ALSO

Digest::HMAC

oathtool(1)

RFC 4226 RFC 6238

<https://github.com/google/google-authenticator/wiki/Key-Uri-Format>

COPYRIGHT AND LICENSE

Copyright (C) 2020 Jan Baier

This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.

See <http://dev.perl.org/licenses/> for more information.