X-OVH-SPAMCAUSE decoder

spam_decode.py

def decode(msg):
    text = []
    for i in range(0, len(msg), 2):
        text.append(unrot(msg[i: i + 2]))
    return str.join('', text)


def unrot(pair, key=ord('x')):
    offset = 0
    for c in 'cdefgh':
        if c in pair:
            offset = (ord('g') - ord(c)) * 16
            break
    return chr(sum(ord(c) for c in pair) - key - offset)

  
if __name__ == '__main__':
    import sys
    print(decode(sys.argv[1]))

The offset characters (c..g) are alternatingly appended and prepended. So instead of just checking if one of them is in the pair, it is necessary to differentiate between, e.g., fh and hf, by keeping track of even or odd pairs. Check my fork for an update.

Hello,
can you explain me how to use it ?
where i have to put the spamcause string ?
Thanks for your help

The spamcause string is the parameter of the decode function, given as command line parameter in the main.
So in most Python environments, you could use the following:
python spam_decode.py "spamcause string"
(but without the quotes)

Hello and thanks for your answer

you mean
python spam_decode.py my_very_long_string ?

yes thanks a lot it works fine !

Just to know, is it normal that the result is truncated
Thanks again

Can you provide an example? In principle, the entire spamcause string is parsed and decoded.