31 lines
841 B
Rust
31 lines
841 B
Rust
use crate::pow::challenge::Challenge;
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use sha2::{Digest, Sha256};
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use subtle::ConstantTimeEq;
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const ALLOWED: [u8; 4] = *b"0123";
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pub fn verify(challenge: &mut Challenge, nonce: &str) -> bool {
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if challenge.used {
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return false;
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}
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if challenge.is_expired() {
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return false;
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}
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if nonce.len() > 64 {
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return false;
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}
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let input = format!("{}{}", challenge.challenge_string(), nonce);
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let hash = Sha256::digest(input.as_bytes());
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let hex_hash = hex::encode(hash);
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let d = challenge.difficulty as usize;
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let ok = hex_hash.as_bytes().iter().take(d).all(|c| {
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let r = c.ct_eq(&ALLOWED[0]) | c.ct_eq(&ALLOWED[1]) | c.ct_eq(&ALLOWED[2]) | c.ct_eq(&ALLOWED[3]);
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r.unwrap_u8() == 1
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});
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if !ok {
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return false;
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}
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challenge.used = true;
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true
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}
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