Use 32-bit integers for transaction output indexes in single-use seals

[dr-orlovsky]

Bitcoin normally uses VarInt to represent the number of transaction outputs that may be contained in a given transaction and 32-bit integer to reference specific transaction output from other's transaction input. While with the given block size limit transaction containing more than 2^16 outputs can't fit the block, it's better not to diverge from bitcoin data structure. The original reason why 16-bit integers were introduced is to save some storage space for RGB client-validated data; however bitcoin transaction output single-use seals are more generic standard and RGB consensus commitment encoding does not require storage space optimization. RGB P2P protocols and vendor-specific RGB storage may still use 16-bit integers; however this should not be required by the LNP/BP standards.

[rajarshimaitra]

Is this issue still open? I am willing to work on it, if it is.

[dr-orlovsky]

It is opened, you are welcome!

[rajarshimaitra]

To make sure that I understand correctly. The concerning index here is vout right? which is 16 bits and needs to be changed to 32 bits.

rust-lnpbp/src/bp/blind.rs

Lines 25 to 35 in dbd0d32

	pub struct OutpointReveal {
	/// Blinding factor preventing rainbow table bruteforce attack based on
	/// the existing blockchain txid set
	pub blinding: u64,
	/// Txid that should be blinded
	pub txid: Txid,
	/// Tx output number that should be blinded
	pub vout: u16,
	}

[dr-orlovsky]

Correct