package otp
Install
dune-project
Dependency
Authors
Maintainers
Sources
md5=0a0f0946ccc2af37eb34132793785db8
sha512=49d3d444291ccfa430a846090305beb1b6561e89ae40db8d77aa8eac87ed43af24c58dd7e75ca9bfaa3ec5f65af790d67de07057bfcbc37a5bf8d75f291d247e
Description
It relies on the Cryptokit library for cryptography operations, as well as the Base32 library for base32 encoding. The library generate a QR Code with the qrc library. It is tested against all test vectors provided in RFC 6238 and the test suite provides as well a dynamic test which requires the use of an client authenticator (like Google Authenticator or Microsoft Authenticator) as a final test.
README
This OCaml library implements the Time-based One Time Password RFC 6238 with an HMAC-SHA1 algorithm and a 6 digits code. It relies on the Cryptokit library for cryptography operations, as well as the Base32 library for base32 encoding. The library generate a QR Code with the qrc library. It is tested against all test vectors provided in RFC 6238 and the test suite provides as well a dynamic test which requires the use of an client authenticator (like Google Authenticator or Microsoft Authenticator) as a final test.
Get Started
There are two phases to setup an OTP :
- the registration : that's where a secret is shared by the server to the client.
- the authentication : that's when the client enters the 6 digits code to authenticate.
Registration
On the server side :
let rng = Cryptokit.Random.secure_rng in (* create a random generator *)
let s = generate_secret rng in (* generate a secret *)
let u = generate_totp_uri "MyWebSite" s "Michel" in (* embeds this secret into a specificaly crafted URI that authenticators can understand *)
let qr = Otp.uri2qrcode u in (* transform this URI into a QRCode that can be displayed in an html page *)
let file = open_out "test.html" in
let fmt = Format.formatter_of_out_channel file in
let () = Format.fprintf fmt
"<html>
<head></head>
<body>
<h1> TOTP QRCode </h1> %s
</body>
</html>" qr in
let () = Format.pp_print_flush fmt () in
let () = close_out file in
let () = print_endline "\nOpen the file test.html and scann the QRCode with a client OTP (like Microsoft Authenticator)" Authentication
Then for the authentication :
print_endline "Enter the six digit code to authenticate Michel on MyWebSite"
let code = read_line () in
if ((String.length code) != 6) then
print_endline "Error, the code must have 6 and only 6 digits"
else
let digits = Int32.to_int (Int32.of_string code) in
let c = totp_counter () in
let r = verify s c digits in
match r with
| Result.Error e -> print_endline e
| Result.Ok resync -> Printf.printf "The code is good, Michel is authenticated on MyWebSite. Number of unsynchronised steps : %d" resync