ContractId round-trip fails for some values

[nicbus]

Some values come up different after a ContractId round-trip.

By round-trip I mean:

• copy_from_slice
• to_string
• from_str

Here's an example:

use rgbstd::contract::ContractId;
use std::str::FromStr;

fn main() {
    let contract_id = ContractId::copy_from_slice([0u8; 32]).unwrap();

    let contract_id_string = contract_id.to_string();
    println!("contract ID string: {contract_id_string}");

    let result = ContractId::from_str(&contract_id_string);
    println!("contract ID result: {result:?}");
}

This outputs:

contract ID string: rgb:1111111-111111111-111111111-11111112k-9zwp
contract ID result: Err(Unparsable("rgb:1111111-111111111-111111111-11111112k-9zwp"))

The same error is returned by version 0.10.9 (using from_slice instead of copy_from_slice).

[dr-orlovsky]

Ok, I have finally figured out what's going on.

It is the only zero string which has significantly shorter Base58 encoding (32 chars instead of 43/44), so it doesn't has a valid chunking and fails to parse.

The issue is not trivial to solve: we need to refactor all the way the chunking works. For v0.11 I think the better way is to leave the things as they are: contract ids containing all-0 (or starting with at least 16 initial zeros to make length short enough to fail chunking) are all invalid anyway and can't be generated in a real-world scenarious.

[nicbus]

I agree there's no urgency in fixing this.

[dr-orlovsky]

After many attempts to fix it I was able to find an ultimate solution: switch from Base58 to Base64.

Base64 has constant size for a given source binary data - unlike Base58. The only disadvantage is the use of "/" and "-" symbols in standard encoding; but I did a modification to use "@" and "$" instead, and it seems to be working great.

I played with it in ssi for identities and signatures (which we will use in RGB as well) and developed a dedicated baid64 crate to support URL prefixes, parsing, mnemonics etc, like we had in Baid58.

Switching to it in all develop branches and will see how it will go.

[yanganto]

Hi @dr-orlovsky,

May I try this? It is not an urgent issue, I can take this chance to learn more, go through the Contract stuff, and make more test cases.

[dr-orlovsky]

Fixed by moving in beta-6 to baid64 encoding instead of baid58