Merge pull request #47 from sigp/sk-0
Reject secret key zero
diff --git a/src/bls381/core.rs b/src/bls381/core.rs
index 16452ba..c851e34 100644
--- a/src/bls381/core.rs
+++ b/src/bls381/core.rs
@@ -94,9 +94,9 @@
let mut secret_key_bytes = [0u8; MODBYTES];
secret_key_bytes[MODBYTES - SECRET_KEY_BYTES..].copy_from_slice(secret_key);
- // Ensure secret key is in the range [0, r-1].
+ // Ensure secret key is in the range [1, r-1].
let secret_key = Big::from_bytes(&secret_key_bytes);
- if secret_key >= Big::new_ints(&CURVE_ORDER) {
+ if secret_key.is_zilch() || secret_key >= Big::new_ints(&CURVE_ORDER) {
return Err(AmclError::InvalidSecretKeyRange);
}
@@ -1004,6 +1004,32 @@
}
#[test]
+ fn test_secret_key_from_bytes() {
+ let bytes = [0u8; 32];
+ let sk = secret_key_from_bytes(&bytes);
+ assert_eq!(sk, Err(AmclError::InvalidSecretKeyRange));
+
+ let bytes = [255u8; 32];
+ let sk = secret_key_from_bytes(&bytes);
+ assert_eq!(sk, Err(AmclError::InvalidSecretKeyRange));
+
+ let mut bytes = [0u8; 32];
+ bytes[31] = 1;
+ let sk = secret_key_from_bytes(&bytes).unwrap();
+ assert!(sk.is_unity());
+
+ let mut bytes = [255u8; 32];
+ bytes[0] = 0;
+ let sk = secret_key_from_bytes(&bytes).unwrap();
+
+ let mut sk_check = Big::new_int(1);
+ sk_check.shl(31 * 8);
+ sk_check.dec(1);
+ sk_check.norm();
+ assert_eq!(sk, sk_check);
+ }
+
+ #[test]
fn test_secret_key_generation() {
let ikm = [1u8; 32];
let sk = key_generate(&ikm, &[]);
