vusi 0.2.0

ECDSA signature vulnerability analysis library and CLI
Documentation 
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//! Nonce reuse attack implementation

use super::*;
use crate::math::{recover_nonce, recover_private_key, scalar_to_decimal_string};
use crate::signature::group_by_r_and_pubkey;

pub struct NonceReuseAttack;

impl Attack for NonceReuseAttack {
    fn name(&self) -> &'static str {
        "nonce-reuse"
    }

    fn min_signatures(&self) -> usize {
        2
    }

    fn detect(&self, signatures: &[Signature]) -> Vec<Vulnerability> {
        group_by_r_and_pubkey(signatures)
            .into_iter()
            .filter(|g| g.signatures.len() >= 2)
            .map(|group| Vulnerability {
                attack_type: self.name().to_string(),
                group,
            })
            .collect()
    }

    fn recover(&self, vuln: &Vulnerability) -> Option<RecoveredKey> {
        let sigs = &vuln.group.signatures;
        if sigs.len() < 2 {
            return None;
        }

        for i in 0..sigs.len() {
            for j in (i + 1)..sigs.len() {
                if let Some(key) = try_recover_pair(&sigs[i], &sigs[j], &vuln.group.pubkey) {
                    return Some(key);
                }
            }
        }
        None
    }
}

fn try_recover_pair(
    sig1: &Signature,
    sig2: &Signature,
    pubkey: &Option<String>,
) -> Option<RecoveredKey> {
    let k = recover_nonce(&sig1.z, &sig2.z, &sig1.s, &sig2.s)?;
    let priv_key = recover_private_key(&sig1.r, &sig1.s, &sig1.z, &k)?;

    Some(RecoveredKey {
        private_key: priv_key,
        private_key_decimal: scalar_to_decimal_string(&priv_key),
        pubkey: pubkey.clone(),
    })
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::signature::SignatureInput;

    fn make_test_signatures() -> Vec<Signature> {
        vec![
            Signature::try_from(SignatureInput {
                r: "6819641642398093696120236467967538361543858578256722584730163952555838220871"
                    .into(),
                s: "5111069398017465712735164463809304352000044522184731945150717785434666956473"
                    .into(),
                z: "4834837306435966184874350434501389872155834069808640791394730023708942795899"
                    .into(),
                pubkey: None,
                timestamp: None,
            })
            .unwrap(),
            Signature::try_from(SignatureInput {
                r: "6819641642398093696120236467967538361543858578256722584730163952555838220871"
                    .into(),
                s: "31133511789966193434473156682648022965280901634950536313584626906865295404159"
                    .into(),
                z: "108808786585075507407446857551522706228868950080801424952567576192808212665067"
                    .into(),
                pubkey: None,
                timestamp: None,
            })
            .unwrap(),
        ]
    }

    #[test]
    fn test_nonce_reuse_detection() {
        let sigs = make_test_signatures();
        let attack = NonceReuseAttack;
        let vulns = attack.detect(&sigs);
        assert_eq!(vulns.len(), 1);
        assert_eq!(vulns[0].attack_type, "nonce-reuse");
    }

    #[test]
    fn test_nonce_reuse_recovery_real_tx() {
        let sigs = make_test_signatures();
        let attack = NonceReuseAttack;
        let vulns = attack.detect(&sigs);
        let recovered = attack.recover(&vulns[0]).unwrap();

        let expected =
            "62958994860637178871299877498639209302063112480839791435318431648713002718353";
        assert_eq!(recovered.private_key_decimal, expected);
    }

    #[test]
    fn test_no_false_positives_different_r() {
        let sigs = vec![
            Signature::try_from(SignatureInput {
                r: "123".into(),
                s: "456".into(),
                z: "789".into(),
                pubkey: None,
                timestamp: None,
            })
            .unwrap(),
            Signature::try_from(SignatureInput {
                r: "999".into(),
                s: "111".into(),
                z: "222".into(),
                pubkey: None,
                timestamp: None,
            })
            .unwrap(),
        ];
        let attack = NonceReuseAttack;
        let vulns = attack.detect(&sigs);
        assert!(vulns.is_empty());
    }
}