from base64 import urlsafe_b64decode, urlsafe_b64encode
from django.db import models
from ecdsa import NIST256p, SigningKey
class VAPIDKeyset(models.Model):
private_key = models.BinaryField(max_length=43)
def __str__(self):
return "public_key:{}... private_key:{}...".format(
self.public_key[:10],
self.private_key.tobytes()[:10]
)
@property
def public_key(self):
key_str = self.private_key.tobytes()
padding = len(key_str) % 4
key_str += b"=" * padding
key = SigningKey.from_string(
urlsafe_b64decode(key_str),
curve=NIST256p
).get_verifying_key()
return urlsafe_b64encode(b"\x04" + key.to_string()).strip(b"=")
