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Created January 12, 2014 18:33
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This is a python script to verify rolls on just-dice.com
#!/usr/bin/env python
import hmac
import hashlib
from sys import argv, exit, stderr
def hmac_sha512(key, message):
return hmac.new(key, message, hashlib.sha512).hexdigest()
def roll(server_seed, client_seed, nonce):
# Generate key and message strings.
key = '%s:%s:%s' % (nonce, server_seed, nonce)
message = '%s:%s:%s' % (nonce, client_seed, nonce)
# Generate hmac-sha512 hash.
hexdigest = hmac_sha512(key, message)
# Convert hexdigest into "lucky" number.
for i in xrange(25):
lucky = int(hexdigest[5*i:5*i+5], 16)
if lucky < 1000000:
return lucky/10000.0
# If none of the 25 blocks were suitable, use the last 3 characters.
lucky = int(hexdigest[-3:], 16)
return lucky/10000.0
def verify_server_seed(server_seed, server_seed_hash):
return hashlib.sha256(server_seed).hexdigest() == server_seed_hash
def usage():
msg = 'usage: server_hash server_seed client_seed start_nonce [end_nonce]\n'
stderr.write(msg)
exit(1)
def main():
if len(argv) < 5:
stderr.write('too few arguments\n')
usage()
server_hash = argv[1]
server_seed = argv[2]
client_seed = argv[3]
start_nonce = argv[4]
if len(argv) > 5:
end_nonce = argv[5]
else:
end_nonce = start_nonce
if verify_server_seed(server_seed, server_hash):
print 'server seed matches hash'
else:
print 'server seed does not match hash!'
exit(0)
print '%5s: %8s' % ('nonce', 'lucky')
for nonce in xrange(int(start_nonce), int(end_nonce)+1):
print '%5s: %8.4f' %(nonce, roll(server_seed, client_seed, nonce))
if __name__ == '__main__':
main()
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