86 lines
2.9 KiB
Python
86 lines
2.9 KiB
Python
#!/usr/bin/python3
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"""
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================================================================================================
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The VAA Signature Verify Stateless Program
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(c) 2021 Randlabs, Inc.
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------------------------------------------------------------------------------------------------
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This program verifies a subset of the signatures in a VAA against the guardian set. This
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program works in tandem with the VAA Processor stateful program.
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================================================================================================
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"""
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from pyteal.ast import *
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from pyteal.types import *
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from pyteal.compiler import *
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from pyteal.ir import *
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from globals import get_sig_count_in_step, get_group_size
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@Subroutine(TealType.uint64)
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def sig_check(signatures, digest, keys):
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si = ScratchVar(TealType.uint64)
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ki = ScratchVar(TealType.uint64)
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return Seq(
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[
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For(Seq([
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si.store(Int(0)),
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ki.store(Int(0))
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]),
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si.load() < Len(signatures),
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Seq([
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si.store(si.load() + Int(66)),
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ki.store(ki.load() + Int(32)),
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])).Do(
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Seq(
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Assert(Ed25519Verify(
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digest,
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Extract(signatures, si.load(), Int(66)),
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Extract(keys, ki.load(), Int(32)),))
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)
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),
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Return(Int(1))
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]
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)
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"""
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* Let N be the number of signatures per verification step, for the TX(i) in group, we verify signatures [j..k] where j = i*N, k = j+(N-1)
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* Input 0 is signatures [j..k] to verify as LogicSigArgs.
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* Input 1 is signed digest of payload, contained in the note field of the TX in current slot.
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* Input 2 is public keys for guardians [j..k] contained in the first Argument of the TX in current slot.
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* Input 3 is guardian set size contained in the second argument of the TX in current slot.
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"""
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def vaa_verify_program(vaa_processor_app_id):
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signatures = Arg(0)
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digest = Txn.note()
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keys = Txn.application_args[1]
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num_guardians = Txn.application_args[2]
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return Seq([
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Assert(And(
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Txn.fee() <= Int(1000),
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Txn.application_args.length() == Int(1),
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Len(signatures) == get_sig_count_in_step(
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Txn.group_index(), Btoi(num_guardians)) * Int(66),
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Txn.rekey_to() == Global.zero_address(),
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Txn.application_id() == Int(vaa_processor_app_id),
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Txn.type_enum() == TxnType.ApplicationCall,
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Global.group_size() == get_group_size(Btoi(num_guardians)),
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sig_check(signatures, digest, keys, num_guardians))
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),
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Approve()])
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if __name__ == "__main__":
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with open("vaa-verify.teal", "w") as f:
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compiled = compileTeal(vaa_verify_program(
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333), mode=Mode.Signature, version=5)
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f.write(compiled)
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