mOTP algorithm in Ruby under a permissive license. Permission has been granted by original author Matthias Straub to redistribute the mOTP algorithm under the MIT License.

motp.rb

# mOTP algorithm in Ruby under a permissive license. Permission has been granted by original author Matthias Straub
# to redistribute the mOTP algorithm under the MIT License.
# References: https://github.com/elliotwutingfeng/motp/blob/main/CREDITS.md and https://motp.sourceforge.net
require 'openssl'

secret = '0123456789ABCDEF'
pin = '0000'
period = 10
digits = 6
unix_seconds = Time.now.to_i

puts OpenSSL::Digest::MD5.hexdigest("#{unix_seconds / period}#{secret}#{pin}")[0..digits - 1]

# MIT License

# Copyright (c) 2024 Wu Tingfeng <wutingfeng@outlook.com>

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.