#!/usr/bin/env python

import base64
import ipaddress
import sys

try:
    from hashlib import blake2s
except ImportError:
    try:
        from pyblake2 import blake2s
    except ImportError:
        print('No native BLAKE2 support; please pip install pyblake2')
        raise

LL_NET_PART = int(ipaddress.IPv6Address('fe80::'))
        
def pubkey_to_lladdr(pubkey):
    # Check / normalize public key to raw bytes.
    if isinstance(pubkey, str):
        pubkey = base64.b64decode(pubkey)
    elif isinstance(pubkey, bytes):
        if len(pubkey) != 32:
            pubkey = base64.b64decode(pubkey)
    else:
        raise TypeError()
    assert len(pubkey) == 32

    # Hash and generate interface part
    pk_hash = blake2s(pubkey, digest_size=8)
    node = int.from_bytes(pk_hash.digest(), 'big')

    # Combine with link-local net part.
    addr = ipaddress.IPv6Address(LL_NET_PART + node)
    return addr

def main():
    pubkey = sys.argv[1]
    addr = pubkey_to_lladdr(pubkey)
    print(str(addr))

if __name__ == '__main__':
    main()