Update Recipient Signature generation reference code in python

[longbowlu]

I've verified this snippet of code against testnet

[n4ss]

I think it will be easier to read if we keep it very explicit. wdyt of:

from pylibra import lcs
from pylibra import libra_types as libra
from pylibra import serde_types as st
...

metadata: Metadata = libra.Metadata__TravelRuleMetadata(
  libra.TravelRuleMetadata__TravelRuleMetadataVersion0(
    libra.TravelRuleMetadataV0(
      off_chain_reference_id="reference_id",
    )
  )
)
// `lcs_metadata` will be used as the `metadata` parameter in encode_peer_to_peer_with_metadata_script()
lcs_metadata = lcs.serialize(metadata, libra.Metadata)

dual_attest_msg_bytes: bytearray = bytearray()
dual_attest_msg_bytes.extend(lcs_metadata)  # Travel Rule metadata
dual_attest_msg_bytes.extend(lcs.serialize(bytes.fromhex("793251de1a61e9b4d1a17d13aa015e45"), bytes))  # Raw on-chain address (https://github.com/libra/lip/blob/master/lips/lip-5.md#terminology)
dual_attest_msg_bytes.extend(lcs.serialize(st.uint64(1000000), st.uint64))  # Amount
dual_attest_msg_bytes.extend(b"@@$$LIBRA_ATTEST$$@@")  # ASCII-encoded Libra Domain Separator string

// We sign the bytes directly with the compliance private key
// `receiver_metadata_signature` will be used as the `metadata_signature` parameter in  encode_peer_to_peer_with_metadata_script()
receiver_metadata_signature = compliance_private_key.sign(dual_attest_msg_bytes)

[bors-libra]

:exclamation: Invalid command

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[longbowlu]

I think it will be easier to read if we keep it very explicit. wdyt of:

from pylibra import lcs
from pylibra import libra_types as libra
from pylibra import serde_types as st
...

metadata: Metadata = libra.Metadata__TravelRuleMetadata(
  libra.TravelRuleMetadata__TravelRuleMetadataVersion0(
    libra.TravelRuleMetadataV0(
      off_chain_reference_id="reference_id",
    )
  )
)
// `lcs_metadata` will be used as the `metadata` parameter in encode_peer_to_peer_with_metadata_script()
lcs_metadata = lcs.serialize(metadata, libra.Metadata)

dual_attest_msg_bytes: bytearray = bytearray()
dual_attest_msg_bytes.extend(lcs_metadata)  # Travel Rule metadata
dual_attest_msg_bytes.extend(lcs.serialize(bytes.fromhex("793251de1a61e9b4d1a17d13aa015e45"), bytes))  # Raw on-chain address (https://github.com/libra/lip/blob/master/lips/lip-5.md#terminology)
dual_attest_msg_bytes.extend(lcs.serialize(st.uint64(1000000), st.uint64))  # Amount
dual_attest_msg_bytes.extend(b"@@$$LIBRA_ATTEST$$@@")  # ASCII-encoded Libra Domain Separator string

// We sign the bytes directly with the compliance private key
// `receiver_metadata_signature` will be used as the `metadata_signature` parameter in  encode_peer_to_peer_with_metadata_script()
receiver_metadata_signature = compliance_private_key.sign(dual_attest_msg_bytes)

Seems like the only difference of this and the original code is DOMAIN_SEPARATOR is not serialized? I tried this and it did not work. Did you test this snippet in testnet ? @n4ss

[n4ss]

Differences are: domain separator is not serialized and the byte vector is not serialized either. This is the same as your implem (lcs-encoding of the struct is lcs-encoding of each field) and matches the ref this time:

        let message = metadata;
        Vector::append(&mut message, LCS::to_bytes(&payer));
        Vector::append(&mut message, LCS::to_bytes(&deposit_value));
        Vector::append(&mut message, DOMAIN_SEPARATOR);
        message

https://github.com/libra/libra/blob/906bfb40984538ca3773ab5c2aaa911aab517b8b/language/stdlib/modules/DualAttestation.move#L325

[longbowlu]

lcs.serialize(bytes.fromhex("793251de1a61e9b4d1a17d13aa015e45"), bytes) is not the correct serialization for address. I think it's because the address has a different type than normal bytes. You can get the lcs bytes by calling utils.account_address(addr_hex).lcs_serialize()

and If your point is dataclass is less clear to read, I've updated to also include a version that concats individually serialized bytes (very similar to the original code snippet before this change)