Pubkeys

The Pubkey class is used for both actual public keys, and addresses that are off the ed25519 curve (e.g. program-derived addresses).

Checking if an address has a private key

Program-derived addresses (PDAs) do not lie on the ed25519 curve and thus do not have private keys.

from solders.pubkey import Pubkey

# Note that Keypair() will always give a public key that is valid for users
key = Pubkey.from_string('5oNDL3swdJJF1g9DzJiZ4ynHXgszjAEpUkxVYejchzrY') # Valid public key
assert key.is_on_curve() # Lies on the ed25519 curve and is suitable for users

off_curve_address = Pubkey.from_string('4BJXYkfvg37zEmBbsacZjeQDpTNx91KppxFJxRqrz48e') # Valid public key
assert not off_curve_address.is_on_curve() # Not on the ed25519 curve, therefore not suitable for users

Generating PDAs

The find_program_address static method takes an array of seed bytes and tries adding a “bump” byte until it finds an off-curve address (i.e. a PDA):

from solders.pubkey import Pubkey

program_id = Pubkey.from_string("G1DCNUQTSGHehwdLCAmRyAG8hf51eCHrLNUqkgGKYASj")
pda, bump = Pubkey.find_program_address([b"test"], program_id)
print(f"bump: {bump}; pda: {pda}")

bump: 253; pda: AfEjen5hHkTkEqy2yfyPhDQWq7dc7zbWU2aJmB3h8brU