Basic terminal-console functionallity

[GiorgosXou]

This might be handy for some people... eg. today i had to use your library for pip two-factor authentication... But feel free to change anything or even drop this pull-request if you think otherwise.

>  pyotp --help
usage: pyotp [-h] [--hotp NUMBER] [--hex] [-v] [secret]

positional arguments:
  secret         base32 secret

options:
  -h, --help     show this help message and exit
  --hotp NUMBER  specify HOTP position\number
  --hex          returns a 40-character hex-encoded secret
  -v, --version  show program's version number and exit

Generate a 32-character base32 secret:

> pyotp
BQ5NYTKAEIDXVF24W5HM2BK7K2TTBEKE

... hex-encoded:

> pyotp --hex
FD5FF5943E44373F4062773365EE865C5196D56B

Get TOTP digits:

> pyotp BQ5NYTKAEIDXVF24W5HM2BK7K2TTBEKE
378127

Get HOTP digits

> pyotp BQ5NYTKAEIDXVF24W5HM2BK7K2TTBEKE --hotp 0
398346

peace and love

[peterthomassen]

Secret should be read from stdin (not passed as an argument) as it can otherwise be observed by other users on the same machine (by inspecting the process list).

[GiorgosXou]

@peterthomassen how about:

> pyotp -h
PyOTP v.2.9.0 usage:
  pyotp  - Generate a 32-character base32 secret
  pyotph - Generate a  hex-encoded base32 secret
  pytotp - Return TOTP digits from base32 secret
  pyhotp - Return HOTP digits from base32 secret

> pyotp
C5B7WOU3VTI6CHGQZCYQX7VPFT2W257E

> pyotph
74524F37F12534CA383162CBB56A433776CAC65B

> pytotp
Enter base32 secret: C5B7WOU3VTI6CHGQZCYQX7VPFT2W257E
983511

> pyhotp
Enter base32 secret: C5B7WOU3VTI6CHGQZCYQX7VPFT2W257E
Enter number: 23
983754

Simple, yet intuitive.

[peterthomassen]

Another option would be to allow passing the secret in a file, and allow the filename to be /dev/stdin (or - for short).