validation: add CryptoOps trait (#9297)

* validation: add CryptoOps trait

Signed-off-by: William Woodruff <william@trailofbits.com>

* validation: rename: backend -> ops

Signed-off-by: William Woodruff <william@trailofbits.com>

---------

Signed-off-by: William Woodruff <william@trailofbits.com>

Author: woodruffw

src/rust/cryptography-x509-validation/src/lib.rs

@@ -4,4 +4,5 @@
 
 #![forbid(unsafe_code)]
 
+pub mod ops;
 pub mod types;

src/rust/cryptography-x509-validation/src/ops.rs

@@ -0,0 +1,18 @@
+// This file is dual licensed under the terms of the Apache License, Version
+// 2.0, and the BSD License. See the LICENSE file in the root of this repository
+// for complete details.
+
+use cryptography_x509::certificate::Certificate;
+
+pub trait CryptoOps {
+    /// A public key type for this cryptographic backend.
+    type Key;
+
+    /// Extracts the public key from the given `Certificate` in
+    /// a `Key` format known by the cryptographic backend.
+    fn public_key(&self, cert: &Certificate) -> Self::Key;
+
+    /// Verifies the signature on `Certificate` using the given
+    /// `Key`.
+    fn is_signed_by(&self, cert: &Certificate, key: Self::Key) -> bool;
+}