First, call GET /get_pow_challenge which will return something like this:
{
"nonce": "<16 byte hex string>",
"difficulty": <0 to 255>
}This will only fail if you call it over IPv6, where it will respond with a 503 SERVICE UNAVAILABLE code.
As the client, you are challenged to then find a solution where:
// b"alpen labs faucet 2024"
let salt = 0x616c70656e206c616273206661756365742032303234;
// nonce is the 16 decoded bytes from the API
// solution is a 8 byte array
// `|` is representing concatenation
return count_leading_zeros(sha256(salt | nonce | solution)) >= difficulty;
fn count_leading_zeros(data: &[u8]) -> u8 {
let mut leading_zeros = 0;
for byte in data {
if *byte == 0 {
leading_zeros += 8;
} else {
leading_zeros += byte.leading_zeros() as u8;
break;
}
}
leading_zeros
}For those who are compiler challenged, there are 0-dependency JavaScript and Python implementations of solvers in the utils directory. You can easily run the JS solver in your browser by running just html-solver and then navigating to http://localhost:3001.
Once you find a solution, hex encode it and use it in a claim for either L1 or L2 funds:
GET /claim_l1/<solution_as_hex>/<l1_address>
Where l1_address is the address that you want to receive funds on.
If successful, this will return a 200 OK with the hex-encoded txid in the body.
If not, it will return a status code and a raw error message string in the body.
GET /claim_l2/<solution_as_hex>/<l2_address>
Where l2_address is the address that you want to receive funds on.
If successful, this will return a 200 OK with the hex-encoded txid in the body.
If not, it will return a status code and a raw error message string in the body.
This work is dual-licensed under MIT and Apache 2.0. You can choose between one of them if you use this work.