Mint SNRC-20

Off-Chain Calculation

Firstly, for any mint operation, we need to prepare the following standard inscription format similar to BRC-20, but without amt:

{ 
  "p": "snrc-20",
  "op": "mint",
  "tick": "tick"
}

At the same time, to be compatible with the ETHS standard, we also need to satisfy the validation of contentURI. Therefore, the final Mint inscription format involved in the calculation is as follows:

data:,{ 
  "p": "snrc-20",
  "op": "mint",
  "tick": "tick"
}

Next, we need to calculate the Poseidon Hash of the fixed part of the Mint inscription. The complete Cairo program code is as follows(The following code block is editable and runnable) :

use core::serde::Serde;
use core::poseidon::PoseidonTrait;
use core::byte_array::ByteArrayTrait;
use core::hash::{HashStateTrait, HashStateExTrait};
use core::array::{ArrayTrait, SpanTrait};
use core::traits::{Into, TryInto};

fn main() -> felt252 {
    /// Replace this with your own data. Be careful you should stringify it first.
    let tick = 'nwhp';
    let payload_pref: ByteArray = "data:,{\"p\":\"snrc-20\",\"op\":\"mint\",\"tick\":\"";
    let payload_remain: ByteArray = "\"}";
    let mut output_array = ArrayTrait::<felt252>::new();
    let mut i: usize = 0;
    /// This is the same as `let serialized = payload.serialize(ref output_array);`
    /// , but it still not supported by the online compiler
    ///
    loop {
        if i >= payload_pref.len() {
            break;
        }
        let char = payload_pref.at(i).unwrap();
        char.serialize(ref output_array);
        i += 1;
    };
    tick.serialize(ref output_array);
    let mut i: usize = 0;
    loop {
        if i >= payload_remain.len() {
            break;
        }
        let char = payload_remain.at(i).unwrap();
        char.serialize(ref output_array);
        i += 1;
    };
    core::poseidon::poseidon_hash_span(output_array.span())
}

The return value of this Cairo program is

1469956484733314490006856178496349941983860913245365919661958978345090908382,

represented in hex as

0x33FF744581AA76AFA81006908ADC9A41B68FACB15ECF5E980EF56F9910380DE.

This is the hash value corresponding to the Mint operation.

Through this hash value, we will be able to identify what operations the user has performed on chain in the indexer, and restore the complete inscription by searching the hash table.

Mint an inscription by a SNRC-20 Contract

When users mint in a contract that meets the SNRC-20 standard, they need to organize their input in the following format:

Referring to the Lim field in the previous Deploy operation example, we can set Amount to 19770525.

Therefore, the input value in this example should be:

"Mint_hash": "0x33FF744581AA76AFA81006908ADC9A41B68FACB15ECF5E980EF56F9910380DE"
"Amount": 19770525

Then, the contract that complies with the SNRC-20 standard will inscribe the above input into the L2->L1 Message and emit an event.