This is a simple Node.js script to generate Time-based One-Time Passwords (TOTP) based on a shared secret. It supports customizable time steps and OTP digit lengths.

./gentotp --secret <SECRET> [--time-step <STEP>] [--digits <DIGITS>]
# or
./gentotp -s <SECRET> [-t <STEP>] [-d <DIGITS>]

• --secret, -s: The TOTP secret (required).
• --time-step, -t: The time step in seconds (default is 30 seconds).
• --digits, -d: The number of digits in the OTP (default is 6 digits).

$ ./gentotp --secret JBSWY3DPEHPK3PXP
$ ./gentotp -s JBSWY3DPEHPK3PXP -t 30 -d 6
492039

To extract the secret from a QR code image, you can use online tools such as:

• google otp decoder (repository)
  This project references decodeGoogleOTP
  See 从Google Authenticator解密获取2FA密钥备份教程 - 知乎