stockholm/krebs/5pkgs/simple/syncthing-device-id.nix

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{ openssl, writePython2Bin }:
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writePython2Bin "syncthing-device-id" {
flakeIgnore = [
"E226"
"E302"
"E305"
"E501"
"F401"
];
} /* python */ ''
import base64
import hashlib
import subprocess
import sys
B32ALPHABET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567'
def luhn_checksum(data, alphabet=B32ALPHABET):
n = len(alphabet)
number = tuple(alphabet.index(i) for i in reversed(data))
result = (sum(number[::2]) +
sum(sum(divmod(i * 2, n)) for i in number[1::2])) % n
return alphabet[-result]
def main(incert):
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der_data = subprocess.check_output([
'${openssl}/bin/openssl',
'x509',
'-outform',
'DER',
], stdin=incert)
data_hash = hashlib.sha256(der_data)
b32_hash = base64.b32encode(data_hash.digest()).decode('ascii')
result = b32_hash.upper().rstrip('=')
blocks = [result[pos:pos+13] for pos in range(0, len(result), 13)]
result = '''.join(block + luhn_checksum(block) for block in blocks)
blocks = [result[pos:pos+7] for pos in range(0, len(result), 7)]
print('-'.join(blocks))
if __name__ == '__main__':
import argparse
parser = argparse.ArgumentParser(description='Generate syncthing ID from certificate')
parser.add_argument('incert', type=argparse.FileType('rb'), help='Certificate path')
args = parser.parse_args()
main(**vars(args))
''