Drop From<Keypair> for secp256k1::PublicKey
What the developer wrote
Authored by Mitchell Bagot
Drop From<Keypair> for secp256k1::PublicKey
Generally, we want to avoid allowing users to trivially convert to secp
types from the bitcoin types. In the case of Keypair, the implicit
conversion to a secp PublicKey is only used in a single test case. It
should instead be removed.
Drop From<Keypair> for secp256k1::PublicKey and adjust
public_key_constructors test accordingly.
What changed, and why it matters
This commit removes a convenience conversion that let users turn a Bitcoin-style key pair directly into a lower-level secp256k1 public key. The change is defensive: it makes it slightly harder to accidentally mix the library's own key types with raw secp256k1 types, which can help prevent API misuse. There is no direct bug or exploit being fixed.
No urgent action. Treat as a minor API cleanup. Downstream users relying on `secp256k1::PublicKey::from(keypair)` should replace it with `keypair.to_public_key().to_inner()`.
Security signals we found
Removal of an implicit type conversion between library key types and raw secp256k1 types
Defensive API hardening to discourage mixing of abstraction layers
No memory safety, cryptographic, or authorization flaw is patched
Evidence from the diff
The patch deletes impl From<Keypair> for secp256k1::PublicKey from crypto/src/key.rs. That implementation simply called kp.to_public_key().to_inner(). The only in-tree caller was a test, which now performs those two calls explicitly. The commit message frames this as a design-hardening change to avoid trivial conversions from bitcoin types to secp types.
Changed components
crypto/src/key.rsbitcoin::crypto::key::Keypairsecp256k1::PublicKey conversion traitInspect captured patch +3 / −7
diff --git a/crypto/src/key.rs b/crypto/src/key.rs
index d48b6c87..e51dd2e9 100644
--- a/crypto/src/key.rs
+++ b/crypto/src/key.rs
@@ -558,10 +558,6 @@ impl From<secp256k1::Keypair> for Keypair {
fn from(pk: secp256k1::Keypair) -> Self { Self::from_secp(pk) }
}
-impl From<Keypair> for secp256k1::PublicKey {
- fn from(kp: Keypair) -> Self { kp.to_public_key().to_inner() }
-}
-
impl From<PrivateKey> for Keypair {
fn from(pk: PrivateKey) -> Self { Self::from(&pk) }
}
@@ -2000,10 +1996,10 @@ mod tests {
#[cfg(feature = "rand")]
#[cfg(feature = "std")]
fn public_key_constructors() {
- let kp = Keypair::generate();
+ let pk = Keypair::generate().to_public_key().to_inner();
- let _ = LegacyPublicKey::from_secp(kp.clone());
- let _ = LegacyPublicKey::from_secp_uncompressed(kp);
+ let _ = LegacyPublicKey::from_secp(pk);
+ let _ = LegacyPublicKey::from_secp_uncompressed(pk);
}
#[test]
Why this scored 16/100
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