youtube-dl/devscripts/gh-pages/sign-versions.py

#!/usr/bin/env python3

import rsa
import json
from binascii import hexlify

try:
    input = raw_input
except NameError:
    pass

versions_info = json.load(open('update/versions.json'))
if 'signature' in versions_info:
    del versions_info['signature']

print('Enter the PKCS1 private key, followed by a blank line:')
privkey = b''
while True:
    try:
        line = input()
    except EOFError:
        break
    if line == '':
        break
    privkey += line.encode('ascii') + b'\n'
privkey = rsa.PrivateKey.load_pkcs1(privkey)

signature = hexlify(rsa.pkcs1.sign(json.dumps(versions_info, sort_keys=True).encode('utf-8'), privkey, 'SHA-256')).decode()
print('signature: ' + signature)

versions_info['signature'] = signature
json.dump(versions_info, open('update/versions.json', 'w'), indent=4, sort_keys=True)