M365 user and Open Authentication (OATH)

Guestbook

Prerequisites

A Microsoft M365 user, work / school account, with M365 Copilot, premium or not.

Setting up a customised Authentication, without using the Microsoft Authenticator:

Add a sign-in method

  • Install Microsoft Authenticator

Choose ‘Set up a different authentication app’.

Install Microsoft Authenticator

  • Set up your account in app

Click next.

Set up your account in app

  • Scan the QR code

Select ‘Can’t scan the QR code?’.

Scan the QR code

  • Enter the following into Authenticator

Copy the Secret key, which is a base32 encoded.

Enter the following into Authenticator

Generate a 6-digit code from the secret key to finish enrollment, with oathtool.

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$ oathtool --totp -b "THE_BASE32_SECRET"
732501

Then paste the seed / secret key into the password manager, and enter that generated 6-digit code.

Concepts

  • oathtool is a command-line utility used to generate and validate Open Authentication (OATH) one-time passwords.
  • TOTP (Time-based One Time Password): Generates time variant codes (default 30-second steps, supports SHA1, SHA256, and SHA512).
  • HOTP (HMAC-based One Time Password): Generates event-based counters by default.

References