Need some help confirming transactions using sha256

[Christian Heimes]

Am 31.01.2013 18:55, schrieb Peter Pearson:
>>>> txid = 'r7A7clvs9waizF+6QEiI0tgAq1ar48JItK3kg9kaeAFXz2vsMsHmOd9r9fhkmtxTz3CQnGAPMaDeKLvgb1A2VA'
>>>> secret = '10812806653842663997bf5971637f86f26c71a4716276d7fa8f323a83588d91:1'
>>>> hashlib.sha256(txid+":"+secret).hexdigest()
> 'dfa8769be81a543002865c88a5b52fa07f3b67fc7cd9b519c3f6a6452bcd48e4'
>>>> 0x48e4
> 18660
>>>>
> 
> .. . . which is the number you wanted, right?

Kryptox, you have chosen the correct algorithm to calculate a MAC. Very
good!

But the designers of the game are using an improper algorithm.
Apparently they don't know much about cryptography, especially length
extension attacks ...

Christian