ethereum.prague.vm.precompiled_contracts.bls12_381.bls12_381_pairing
Ethereum Virtual Machine (EVM) BLS12 381 PAIRING PRE-COMPILE ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. contents:: Table of Contents :backlinks: none :local:
Introduction
Implementation of the BLS12 381 pairing pre-compile.
bls12_pairing
The bls12_381 pairing precompile.
Parameters
evm : The current EVM frame.
Raises
InvalidParameter If the input length is invalid or if sub-group check fails.
def bls12_pairing(evm: Evm) -> None:
27 | """ |
---|---|
28 | The bls12_381 pairing precompile. |
29 |
|
30 | Parameters |
31 | ---------- |
32 | evm : |
33 | The current EVM frame. |
34 |
|
35 | Raises |
36 | ------ |
37 | InvalidParameter |
38 | If the input length is invalid or if sub-group check fails. |
39 | """ |
40 | data = evm.message.data |
41 | if len(data) == 0 or len(data) % 384 != 0: |
42 | raise InvalidParameter("Invalid Input Length") |
43 | |
44 | # GAS |
45 | k = len(data) // 384 |
46 | gas_cost = Uint(32600 * k + 37700) |
47 | charge_gas(evm, gas_cost) |
48 | |
49 | # OPERATION |
50 | result = FQ12.one() |
51 | for i in range(k): |
52 | g1_start = Uint(384 * i) |
53 | g2_start = Uint(384 * i + 128) |
54 |
|
55 | g1_point = bytes_to_g1(data[g1_start : g1_start + Uint(128)]) |
56 | if not is_inf(bls12_multiply(g1_point, curve_order)): |
57 | raise InvalidParameter("Sub-group check failed for G1 point.") |
58 |
|
59 | g2_point = bytes_to_g2(data[g2_start : g2_start + Uint(256)]) |
60 | if not is_inf(bls12_multiply(g2_point, curve_order)): |
61 | raise InvalidParameter("Sub-group check failed for G2 point.") |
62 |
|
63 | result *= pairing(g2_point, g1_point) |
64 | |
65 | if result == FQ12.one(): |
66 | evm.output = b"\x00" * 31 + b"\x01" |
67 | else: |
68 | evm.output = b"\x00" * 32 |