add fuzz target for unhardened key derivation, signing and verification

chia-bls/fuzz/.gitignore

@@ -0,0 +1,3 @@
+target
+corpus
+artifacts

chia-bls/fuzz/Cargo.toml

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+[package]
+name = "chia-bls-fuzz"
+version = "0.0.0"
+authors = ["Automatically generated"]
+publish = false
+edition = "2018"
+
+[package.metadata]
+cargo-fuzz = true
+
+[dependencies]
+libfuzzer-sys = "0.4"
+
+[dependencies.chia-bls]
+path = ".."
+
+# Prevent this from interfering with workspaces
+[workspace]
+members = ["."]
+
+[[bin]]
+name = "derive"
+path = "fuzz_targets/derive.rs"
+test = false
+doc = false

chia-bls/fuzz/fuzz_targets/derive.rs

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+#![no_main]
+use libfuzzer_sys::fuzz_target;
+
+use chia_bls::secret_key::SecretKey;
+use chia_bls::public_key::PublicKey;
+use chia_bls::signature::{sign, verify};
+use chia_bls::derivable_key::DerivableKey;
+
+fuzz_target!(|data: &[u8]| {
+    if data.len() < 32 {
+        return;
+    }
+
+    let sk = SecretKey::from_seed(data);
+    let pk = sk.public_key();
+
+    // round-trip SecretKey
+    let bytes = sk.to_bytes();
+    assert_eq!(sk, SecretKey::from_bytes(&bytes).unwrap());
+
+    // round-trip PublicKey
+    let bytes = pk.to_bytes();
+    assert_eq!(pk, PublicKey::from_bytes(&bytes).unwrap());
+
+    // unhardened derivation
+    let sk1 = sk.derive_unhardened(1337);
+    let pk1 = pk.derive_unhardened(1337);
+
+    let sig = sign(&sk1, b"foobar");
+    assert!(verify(&sig, &pk1, b"foobar"));
+
+});