Announcing paperbackup.py to backup keys as QR codes on paper

[Peter Lebbing]

Crap, silly me... why do I always notice these things only after I've
hit send?

On 24/02/17 17:17, Peter Lebbing wrote:
> The following Python:
> 
>>>> from posixcksum import PosixCkSum
>>>> from base64 import b64encode
>>>> crc, _ = PosixCkSum.sum_whole(bytearray(b'123456789'))
>>>> b64encode(crc.to_bytes(4,byteorder='big'))[:4]
> b'N3pg'

Let's make that:

>>> from posixcksum import PosixCkSum
>>> from base64 import b64encode
>>> crc, _ = PosixCkSum.sum_whole(bytearray(b'123456789'))
>>> print(b64encode(crc.to_bytes(4,byteorder='big'))[:6])
b'N3pgEQ'

> $ printf $(printf '%08x' $(echo -n 123456789 | cksum | cut -d' ' -f1) | sed 's/../\\x\0/g')|base64|cut -b-4
> N3pg

And this one:

$ printf $(printf '%08x' $(echo -n 123456789 | cksum | cut -d' ' -f1) |
sed 's/../\\x\0/g')|base64|cut -b-6
N3pgEQ

Oh, and by the way, when the python module is invoked as the main
module, it mimics the working of cksum, so the following two are roughly
equivalent:

$ cksum *.c
$ posixcksum.py *.c

HTH,

Peter.

-- 
I use the GNU Privacy Guard (GnuPG) in combination with Enigmail.
You can send me encrypted mail if you want some privacy.
My key is available at <http://digitalbrains.com/2012/openpgp-key-peter>

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