simpleauthenticator

Cross-platform C#/.Net tool to generate one time passwords for open authentication defined by standard RFC's:

• HOTP: An HMAC-Based One-Time Password Algorithm,
• TOTP: Time-Based One-Time Password Algorithm

Compatible with Google/Microsoft Authenticator and other authenticators that supports corresponding RFC's.

How to run it

Ensure that .Net 10.0 or later is installed

dotnet --version

Clone repository and run totp or hotp command:

git clone https://github.com/AndreyRusyaev/simpleauthenticator
cd simpleauthenticator
dotnet run totp -s "<your base32 encoded secret key>"

Output:

Token: 123456 (valid for 25 seconds).

Prerequisites

.Net 10.0 or higher.

HOWTO: Install .NET 10.0 on Windows, Linux, and macOS

Windows

# run in elevated shell
winget install Microsoft.DotNet.SDK.10

Ubuntu

# Register Microsoft packages feed (https://learn.microsoft.com/en-us/linux/packages)
wget https://packages.microsoft.com/config/ubuntu/$(lsb_release -rs)/packages-microsoft-prod.deb
sudo dpkg -i packages-microsoft-prod.deb
rm packages-microsoft-prod.deb
# installation
sudo apt update && sudo apt-get install -y dotnet-sdk-10.0

MacOS

brew install dotnet

See also

Install .NET on Windows, Linux, and macOS

Usage

Description:
Generates one time passwords (HOTP and TOTP tokens).
Usage:
simpleauthenticator [command] [options]
Options:
--version Show version information
-?, -h, --help Show help and usage information
Commands:
totp Generates time based one time password (TOTP token, RFC 6238).
hotp Generates hmac based one time password (HOTP token, RFC 4226).
totp Command Options:
-s, --secretkey, --secretkey-base32 <secretkey-base32> Base32 encoded secret key (whitespaces allowed). Examples: 'A5YS 2UP6 K4UF 46GD', A5YS2UP6K4UF46GD.
-s64, --secretkey-base64, --secretkey64 <secretkey-base64> Base64 encoded secret key (whitespaces allowed, '=' can be omitted). Example: 'B3Et Uf5X KF54 ww=='.
-l, --token-length <token-length> Token length. Default: 6.
-m, --hmac <Md5|Sha1|Sha2_256|Sha2_512|Sha3_256|Sha3_512> HMAC algorithm to use. Default: SHA1. Allowed values: Md5, Sha1, Sha2_256, Sha2_512, Sha3_256, Sha3_512.
hotp Command Options:
-s, --secretkey, --secretkey-base32 <secretkey-base32> Base32 encoded secret key (whitespaces allowed). Example: 'A5YS 2UP6 K4UF 46GD'.
-s64, --secretkey-base64, --secretkey64 <secretkey-base64> Base64 encoded secret key (whitespaces allowed, '=' can be omitted). Example: 'B3Et Uf5X KF54 ww=='.
-c, --counter <counter> (REQUIRED) 8-byte counter value, the moving factor. This counter MUST be synchronized between the HOTP generator (client) and the HOTP validator (server).
-l, --token-length <token-length> Token length. Default: 6.
-m, --hmac <Md5|Sha1|Sha2_256|Sha2_512|Sha3_256|Sha3_512> HMAC algorithm to use. Default: SHA1. Allowed values: Md5, Sha1, Sha2_256, Sha2_512, Sha3_256, Sha3_512.

Examples

TOTP: Generate time-based one time password

git clone https://github.com/AndreyRusyaev/simpleauthenticator
cd simpleauthenticator
dotnet run totp -s A5YS2UP6K4UF46GD

OR

git clone https://github.com/AndreyRusyaev/simpleauthenticator
cd simpleauthenticator
dotnet run totp -s64 B3EtUf5XKF54ww==

Output:

Token: 316788 (valid for 25 seconds).

HOTP: Generate HMAC-based one time password

git clone https://github.com/AndreyRusyaev/simpleauthenticator
cd simpleauthenticator
dotnet run hotp --counter 12345 -s A5YS2UP6K4UF46GD

OR

git clone https://github.com/AndreyRusyaev/simpleauthenticator
cd simpleauthenticator
dotnet run hotp --counter 12345 -s64 B3EtUf5XKF54ww

Output:

Token: 316788.