onetom's posterous

In short:

paste first8 base64 enc "twitter" pwd?

In more detail:

I just met ecin of copypastel.com in HackerspaceSG last night. He showed me a cool little trick for managing passwords. Have a look at his article for more details and also visit the "original" web based implementation.

I had a look at his BASH implementation on the project homepage and I realized quite fast how this - otherwise quite neat - source code can be chopped down even further if we use the "right tool for the right job" >;P

The heart of the algorithm is this:

openssl dgst -sha1 -hmac $3 -binary | openssl enc -base64 | head -c 8

I have to nail down that the BASH piping is just as beautiful as powerful. It's more readable (at least after many years of experience) than what I translate it into now. BUT I can gain two great benefits if I rewrite it in some other language:

1. cross platformness
2. less dependencies

Let's see the translation pipe-by-pipe into my favorite language:

; head -c 8
first8: func[x] [copy/part x 8]

; openssl enc -base64
base64: func[x] [enbase/base x 64]

; openssl dgst -sha1 -hmac $3 -binary
enc: func[x pwd] [checksum/method/key x 'SHA1 pwd]

; read the password used as the hashing key
pwd?: does [ask/hide "password: "]

; pasting (text) into the clipboard is the least cross platform part of the application
; but with REBOL it's unified too (the 800kB graphical version has this functionality
; for Liunx X11, Windows GDI & Mac Cocoa)
paste: func[x] [write clipboard:// x]

So assembling all these together we get the following program:

paste first8 base64 enc "twitter" pwd?

Can it be more expressive? ;)

It makes the algorithm obvious, however it fits a longer console line, so while I was developing it, I was just typing the following actually:

>> write clipboard:// probe copy/part enbase/base checksum/method/key "twitter" 'SHA1 ask/hide "password: " 64 8
password: ******
"dNbv5KY1"
>> <Apple-V>dNbv5KY1

Conclusion: Fuck complexity. Again. And REBOL rulez, ofcoz...