X-OVH-SPAMCAUSE decoder

spam_decode.py

def decode(msg):
    text = ""
    for i in range(0, len(msg), 2):
        text += unrot(msg[i: i + 2], i // 2)                    # add position as extra parameter
    return text


def unrot(pair, pos, key=ord('x')):
    if pos % 2 == 0:                                            # "even" position => 2nd char is offset
        pair = pair[1] + pair[0]                                # swap letters in pair
    offset = (ord('g') - ord(pair[0])) * 16                     # treat 1st char as offset
    return chr(sum(ord(c) for c in pair) - key - offset)        # map to original character

  
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.

Hello. I need to decode a SPAMCAUSE looong string . How can i do this ?

Hello. I need to decode a SPAMCAUSE looong string . How can i do this ?

It depends: how long is this long string? You could copy-paste it into the python code and use it as value to assign to a variable (instead of passing it as an argument).

Thank you for reply.It is indeed very long. Is it correct to enter the long string on the first line :def decode(the_long_string):         ? Sent from Yahoo Mail on Android On Thu., 17 Nov. 2022 at 5:55 p.m., ***@***.***> wrote: Re: ***@***.*** commented on this gist. Hello. I need to decode a SPAMCAUSE looong string . How can i do this ? It depends: how long is this long string? You could copy-paste it into the python code and use it as value to assign to a variable (instead of passing it as an argument). — Reply to this email directly, view it on GitHub or unsubscribe. You are receiving this email because you commented on a thread. Triage notifications on the go with GitHub Mobile for iOS or Android.                                                            

You could just use this main program, instead of using the sys.argv-approach:

spamcause = <your very long string between quotes>
print(decode(spamcause))

an other way to use this script:

• feed spamcause header in a file whithout "X-VR-SPAMCAUSE: "
• then run

python3 ./ovh-spam-cause.py $(cat /tmp/temp-file) | sed -e "s/;/\n/g"

Here's an online version : https://f3hj7s.csb.app