def deserialize(self, ser_key: str):
"""Deserialize a serialized key into self"""
ser_key = base58_decode(ser_key, 82)
# Checksum
if sha256(sha256(ser_key[:78]))[:4] != ser_key[78:]:
raise ValueError(
"Wrong checksum of the extended key: {:s}".format(ser_key.hex())
)
self.level = ser_key[4]
self.fingerprint = ser_key[5:9]
self.index = bytes2int(ser_key[9:13])
self.chain_code = ser_key[13:45]
if ser_key[:4] == MAINNET_PRIVATE:
# Miss 00 and get the private key
self.key = ser_key[46:78]
elif ser_key[:4] == MAINNET_PUBLIC:
# Get x coordinate of the public point
x = bytes2int(ser_key[46:78])
# Calculate y coordinate of the public point
y = ECPoint.get_secp256k1_y(x)
# Choice even y if prefix = 02, else choice odd y
if ser_key[45] == 2:
y = ECPoint.get_secp256k1_p() - y if y % 2 != 0 else y
else:
y = ECPoint.get_secp256k1_p() - y if y % 2 == 0 else y
self.key = ECPoint(x, y)
else:
raise ValueError(
"Invalid serialized extended key: {:s}".format(ser_key.hex())
)
# --- Usage and testing ---
if __name__ == "__main__":
from btc.ecpoint import ECPoint
# Find the nearest point with x coordinate >= start_x
start_x = 10**33
while True:
try:
p = ECPoint(start_x, ECPoint.get_secp256k1_y(start_x))
break
except AssertionError:
start_x += 1
continue
print(p)