How to use the command 'oathtool' (with examples)
This article will guide you through different use cases of the ‘oathtool’ command, which is a part of the OATH Toolkit. ‘oathtool’ is a versatile command-line tool that allows you to generate and validate one-time passwords (OTPs) using the Time-based One-Time Password (TOTP) algorithm. With ‘oathtool’, you can generate tokens, validate tokens, and even generate tokens for a specific time.
Use case 1: Generate TOTP token (behaves like Google Authenticator)
Code:
oathtool --totp --base32 "secret"
Motivation: Generating TOTP tokens can be useful for implementing two-factor authentication in various applications. By generating a TOTP token, you can enhance the security of your system by requiring users to provide both their password and the current OTP. The ‘–base32’ argument is used to specify the secret key required for generating the TOTP token.
Explanation:
- ‘–totp’: This option instructs ‘oathtool’ to generate a TOTP token.
- ‘–base32 “secret”’: The ‘–base32’ option followed by the secret key in base32 format is used to generate the TOTP token. Replace “secret” with your actual secret key.
Example output:
373592
Use case 2: Generate a TOTP token for a specific time
Code:
oathtool --totp --now "2004-02-29 16:21:42" --base32 "secret"
Motivation: Sometimes, it may be necessary to generate a TOTP token for a specific time, for example, to test the validity of a token at a particular moment in the past or future. This use case allows you to generate a TOTP token using a specific timestamp. The ‘–now’ argument specifies the desired time.
Explanation:
- ‘–totp’: This option tells ‘oathtool’ to generate a TOTP token.
- ‘–now “2004-02-29 16:21:42”’: The ‘–now’ option followed by the desired timestamp is used to generate a TOTP token for that specific time.
- ‘–base32 “secret”’: The ‘–base32’ option followed by the secret key in base32 format is used to generate the TOTP token. Replace “secret” with your actual secret key.
Example output:
004563
Use case 3: Validate a TOTP token
Code:
oathtool --totp --base32 "secret" "token"
Motivation: Validating a TOTP token is essential in scenarios such as user login authentication. By using ‘oathtool’ to validate a TOTP token, you can ensure that the token entered by the user is correct and matches the expected value based on the secret key.
Explanation:
- ‘–totp’: This option specifies that the token being validated is a TOTP token.
- ‘–base32 “secret”’: The ‘–base32’ option followed by the secret key in base32 format is used to validate the TOTP token. Replace “secret” with your actual secret key.
- ‘“token”’: The TOTP token that needs to be validated is provided as an argument.
Example output:
Verification succeeded
Conclusion:
In this article, we explored various use cases of the ‘oathtool’ command. We learned how to generate TOTP tokens, generate tokens for a specific time, and validate TOTP tokens. With its versatility, ‘oathtool’ proves to be a valuable tool for implementing secure two-factor authentication systems.
