158 lines
5.3 KiB
Python
158 lines
5.3 KiB
Python
import base64
|
|
import secrets
|
|
from typing import Optional
|
|
|
|
import secp256k1
|
|
from cffi import FFI
|
|
from cryptography.hazmat.primitives import padding
|
|
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
|
|
|
|
from . import bech32
|
|
from .event import EncryptedDirectMessage, Event
|
|
|
|
|
|
class PublicKey:
|
|
def __init__(self, raw_bytes: bytes) -> None:
|
|
self.raw_bytes = raw_bytes
|
|
|
|
def bech32(self) -> str:
|
|
converted_bits = bech32.convertbits(self.raw_bytes, 8, 5)
|
|
return bech32.bech32_encode("npub", converted_bits, bech32.Encoding.BECH32)
|
|
|
|
def hex(self) -> str:
|
|
return self.raw_bytes.hex()
|
|
|
|
def verify_signed_message_hash(self, message_hash: str, sig: str) -> bool:
|
|
pk = secp256k1.PublicKey(b"\x02" + self.raw_bytes, True)
|
|
return pk.schnorr_verify(
|
|
bytes.fromhex(message_hash), bytes.fromhex(sig), None, True
|
|
)
|
|
|
|
@classmethod
|
|
def from_npub(cls, npub: str):
|
|
"""Load a PublicKey from its bech32/npub form"""
|
|
hrp, data, spec = bech32.bech32_decode(npub)
|
|
assert data, "Invalid npub"
|
|
bits = bech32.convertbits(data, 5, 8)
|
|
assert bits, "Invalid npub"
|
|
raw_public_key = bits[:-1]
|
|
return cls(bytes(raw_public_key))
|
|
|
|
|
|
class PrivateKey:
|
|
def __init__(self, raw_secret: Optional[bytes] = None) -> None:
|
|
if raw_secret is not None:
|
|
self.raw_secret = raw_secret
|
|
else:
|
|
self.raw_secret = secrets.token_bytes(32)
|
|
|
|
sk = secp256k1.PrivateKey(self.raw_secret)
|
|
assert sk.pubkey, "Invalid public"
|
|
self.public_key = PublicKey(sk.pubkey.serialize()[1:])
|
|
|
|
@classmethod
|
|
def from_nsec(cls, nsec: str):
|
|
"""Load a PrivateKey from its bech32/nsec form"""
|
|
hrp, data, spec = bech32.bech32_decode(nsec)
|
|
bits = bech32.convertbits(data, 5, 8)
|
|
assert bits, "Invalid nsec"
|
|
raw_secret = bits[:-1]
|
|
return cls(bytes(raw_secret))
|
|
|
|
def bech32(self) -> str:
|
|
converted_bits = bech32.convertbits(self.raw_secret, 8, 5)
|
|
return bech32.bech32_encode("nsec", converted_bits, bech32.Encoding.BECH32)
|
|
|
|
def hex(self) -> str:
|
|
return self.raw_secret.hex()
|
|
|
|
def tweak_add(self, scalar: bytes) -> bytes:
|
|
sk = secp256k1.PrivateKey(self.raw_secret)
|
|
return sk.tweak_add(scalar)
|
|
|
|
def compute_shared_secret(self, public_key_hex: str) -> bytes:
|
|
pk = secp256k1.PublicKey(bytes.fromhex("02" + public_key_hex), True)
|
|
return pk.ecdh(self.raw_secret, hashfn=copy_x)
|
|
|
|
def encrypt_message(self, message: str, public_key_hex: str) -> str:
|
|
padder = padding.PKCS7(128).padder()
|
|
padded_data = padder.update(message.encode()) + padder.finalize()
|
|
|
|
iv = secrets.token_bytes(16)
|
|
cipher = Cipher(
|
|
algorithms.AES(self.compute_shared_secret(public_key_hex)), modes.CBC(iv)
|
|
)
|
|
|
|
encryptor = cipher.encryptor()
|
|
encrypted_message = encryptor.update(padded_data) + encryptor.finalize()
|
|
|
|
msg = base64.b64encode(encrypted_message).decode()
|
|
return f"{msg}?iv={base64.b64encode(iv).decode()}"
|
|
|
|
def encrypt_dm(self, dm: EncryptedDirectMessage) -> None:
|
|
assert dm.recipient_pubkey, "Recipient public key must be set"
|
|
dm.content = self.encrypt_message(
|
|
message=dm.cleartext_content or "", public_key_hex=dm.recipient_pubkey
|
|
)
|
|
|
|
def decrypt_message(self, encoded_message: str, public_key_hex: str) -> str:
|
|
encoded_data = encoded_message.split("?iv=")
|
|
encoded_content, encoded_iv = encoded_data[0], encoded_data[1]
|
|
|
|
iv = base64.b64decode(encoded_iv)
|
|
cipher = Cipher(
|
|
algorithms.AES(self.compute_shared_secret(public_key_hex)), modes.CBC(iv)
|
|
)
|
|
encrypted_content = base64.b64decode(encoded_content)
|
|
|
|
decryptor = cipher.decryptor()
|
|
decrypted_message = decryptor.update(encrypted_content) + decryptor.finalize()
|
|
|
|
unpadder = padding.PKCS7(128).unpadder()
|
|
unpadded_data = unpadder.update(decrypted_message) + unpadder.finalize()
|
|
|
|
return unpadded_data.decode()
|
|
|
|
def sign_message_hash(self, message_hash: bytes) -> str:
|
|
sk = secp256k1.PrivateKey(self.raw_secret)
|
|
sig = sk.schnorr_sign(message_hash, None, raw=True)
|
|
return sig.hex()
|
|
|
|
def sign_event(self, event: Event) -> None:
|
|
if event.public_key is None:
|
|
event.public_key = self.public_key.hex()
|
|
event.signature = self.sign_message_hash(bytes.fromhex(event.id))
|
|
|
|
def __eq__(self, other):
|
|
return self.raw_secret == other.raw_secret
|
|
|
|
|
|
def mine_vanity_key(
|
|
prefix: Optional[str] = None, suffix: Optional[str] = None
|
|
) -> PrivateKey:
|
|
if prefix is None and suffix is None:
|
|
raise ValueError("Expected at least one of 'prefix' or 'suffix' arguments")
|
|
|
|
while True:
|
|
sk = PrivateKey()
|
|
if (
|
|
prefix is not None
|
|
and not sk.public_key.bech32()[5 : 5 + len(prefix)] == prefix
|
|
):
|
|
continue
|
|
if suffix is not None and not sk.public_key.bech32()[-len(suffix) :] == suffix:
|
|
continue
|
|
break
|
|
|
|
return sk
|
|
|
|
|
|
ffi = FFI()
|
|
|
|
|
|
@ffi.callback(
|
|
"int (unsigned char *, const unsigned char *, const unsigned char *, void *)"
|
|
)
|
|
def copy_x(output, x32, y32, data):
|
|
ffi.memmove(output, x32, 32)
|
|
return 1
|