Go TOTP: TOTP(HOTP) Token Generator

This is a simply TOTP(HOTP) token generator writtin in Go. Inspired by MinTOTP, the source code is translated from Python to Go for easier compiled distribution.

Disclaimer

This is a small hobby project and must not be used in production or secure environment.

How To

Requirements

Following are required to work on the source code locally:

• Go 1.12
• Git
• An IDE of choice

Development

To work on the source code locally, simply clone to your local disk

$ git clone https://github.com/ashraful-islam/gototp.git

Compilation

To compile to usable binary, run following command from inside the project directory

$ go build -o gototp main.go

There should be a new executable binary with name gototp(on Windows, it'll be gototp.exe)

Usage

This is a simply cli based program. To check for available configurable parameters

$ ./gototp -h

Following configuration parameters are available

• -key : the secret key, i.e. seed used to generate the token (default: will try to read from stdin)
• -digits : number(positive integer) of digits the token will be of (default: 6)
• -digest : the hashing algorithm to use, available sha1, sha256, sha512 (default: auto detected if not given)
• -steps : time steps(in seconds) to use for counter (default: 30)

Example using all defaults

$ ./gototp -key=ZYTYYE5FOAGW5ML7LRWUL4WTZLNJAMZS
// following is output
TOKEN: 675179

Example using more digits and different step size

$ ./gototp -key=ZYTYYE5FOAGW5ML7LRWUL4WTZLNJAMZS -digits=8 -digest=sha256
// following is output
TOKEN: 21690441

Example using key passed in stdin from a file

$ echo "ZYTYYE5FOAGW5ML7LRWUL4WTZLNJAMZS" > mykey.txt
$ cat mykey.txt | ./gototp
// following is output
TOKEN: 675179

OR

$ ./gototp <<< ZYTYYE5FOAGW5ML7LRWUL4WTZLNJAMZS
// followin is output
TOKEN: 675179

Example of passing configuration options as well as passing key in stdin

$ echo "ZYTYYE5FOAGW5ML7LRWUL4WTZLNJAMZS" > mykey.txt
$ cat mykey.txt | ./gototp -digits=7
// following is output
TOKEN: 0480559

OR

$ ./gototp -digits=7 <<< ZYTYYE5FOAGW5ML7LRWUL4WTZLNJAMZS
// followin is output
TOKEN: 0480559

WARN: For space separated keys(ones used by Dropbox), pass the key in quotes(") else only one block will be detected!

$ ./gototp <<< "zyty ye5f oagw 5ml7 lrwu l4wt zlnj amzs"
//following is output
TOKEN: 675179

CREDITS:

The project was inspired by MinTOTP by Susam Pal, posted on HackerNew.

The project was translated in Go to generate (cross-)compiled binaries that are easier to distribute & run on most environments.

Some of the minor changes made were introduced following

• RFC-6238