feat(ext/crypto): initial support for p521 in generateKey and `impo…

…rtKey` (#21815)

Part 1 of a potential 3 part series. Ref #13449 

The current implementation passes key material back and forth RustCrypto
group of crates and ring. ring does not implement p521 yet.

This PR adds support for P521 named curve in `generateKey` and
`importKey` where we use RustCrypto. Other parts should be moved over to
the RustGroup group of crates for consistency.

cli/tests/unit/webcrypto_test.ts

@@ -2006,3 +2006,42 @@ Deno.test(async function testHmacJwkImport() {
     ["sign", "verify"],
   );
 });
+
+Deno.test(async function p521Import() {
+  const jwk = {
+    "crv": "P-521",
+    "ext": true,
+    "key_ops": [
+      "verify",
+    ],
+    "kty": "EC",
+    "x":
+      "AXkSI8nfkc6bu3fifXGuKKbu08g5LKPfxUNQJJYzzPgmN8XLDzx0C9Sdeejl1XoWGrheKPHl0k4tUmHw0cdInpfj",
+    "y":
+      "AT4vjsO0bzVRlN3Wthv9DewncDXS2tlTob5QojV8WX1GzOAikRfWFEP3nspoSv88U447acZAsk5IvgGJuVjgMDlx",
+  };
+  const algorithm = { name: "ECDSA", namedCurve: "P-521" };
+
+  const key = await crypto.subtle.importKey(
+    "jwk",
+    jwk,
+    algorithm,
+    true,
+    ["verify"],
+  );
+
+  assert(key instanceof CryptoKey);
+});
+
+Deno.test(async function p521Generate() {
+  const algorithm = { name: "ECDSA", namedCurve: "P-521" };
+
+  const key = await crypto.subtle.generateKey(
+    algorithm,
+    true,
+    ["sign", "verify"],
+  );
+
+  assert(key.privateKey instanceof CryptoKey);
+  assert(key.publicKey instanceof CryptoKey);
+});

ext/crypto/00_crypto.js

@@ -63,8 +63,7 @@ const {
   isDataView,
 } = core;
 
-// P-521 is not yet supported.
-const supportedNamedCurves = ["P-256", "P-384"];
+const supportedNamedCurves = ["P-256", "P-384", "P-521"];
 const recognisedUsages = [
   "encrypt",
   "decrypt",

ext/crypto/Cargo.toml

@@ -30,6 +30,7 @@ num-traits = "0.2.14"
 once_cell.workspace = true
 p256 = { version = "0.13.2", features = ["ecdh"] }
 p384 = "0.13.0"
+p521 = "0.13.3"
 rand.workspace = true
 ring = { workspace = true, features = ["std"] }
 rsa.workspace = true

ext/crypto/generate_key.rs

@@ -84,11 +84,17 @@ fn generate_key_rsa(
   Ok(private_key.as_bytes().to_vec())
 }
 
+fn generate_key_ec_p521() -> Vec<u8> {
+  let mut rng = OsRng;
+  let key = p521::SecretKey::random(&mut rng);
+  key.to_nonzero_scalar().to_bytes().to_vec()
+}
+
 fn generate_key_ec(named_curve: EcNamedCurve) -> Result<Vec<u8>, AnyError> {
   let curve = match named_curve {
     EcNamedCurve::P256 => &ring::signature::ECDSA_P256_SHA256_FIXED_SIGNING,
     EcNamedCurve::P384 => &ring::signature::ECDSA_P384_SHA384_FIXED_SIGNING,
-    _ => return Err(not_supported_error("Unsupported named curve")),
+    EcNamedCurve::P521 => return Ok(generate_key_ec_p521()),
   };
 
   let rng = ring::rand::SystemRandom::new();

ext/crypto/import_key.rs

@@ -520,7 +520,12 @@ fn import_key_ec_jwk_to_point(
 
       p384::EncodedPoint::from_affine_coordinates(&x, &y, false).to_bytes()
     }
-    _ => return Err(not_supported_error("Unsupported named curve")),
+    EcNamedCurve::P521 => {
+      let x = decode_b64url_to_field_bytes::<p521::NistP521>(&x)?;
+      let y = decode_b64url_to_field_bytes::<p521::NistP521>(&y)?;
+
+      p521::EncodedPoint::from_affine_coordinates(&x, &y, false).to_bytes()
+    }
   };
 
   Ok(point_bytes.to_vec())
@@ -629,7 +634,15 @@ fn import_key_ec(
             return Err(data_error("invalid P-384 elliptic curve point"));
           }
         }
-        _ => return Err(not_supported_error("Unsupported named curve")),
+        EcNamedCurve::P521 => {
+          // 1-2.
+          let point = p521::EncodedPoint::from_bytes(&data)
+            .map_err(|_| data_error("invalid P-521 elliptic curve point"))?;
+          // 3.
+          if point.is_identity() {
+            return Err(data_error("invalid P-521 elliptic curve point"));
+          }
+        }
       };
       Ok(ImportKeyResult::Ec {
         raw_data: RustRawKeyData::Public(data.to_vec().into()),
@@ -755,7 +768,18 @@ fn import_key_ec(
 
             point.as_bytes().len()
           }
-          _ => return Err(not_supported_error("Unsupported named curve")),
+          EcNamedCurve::P521 => {
+            let point =
+              p521::EncodedPoint::from_bytes(&*encoded_key).map_err(|_| {
+                data_error("invalid P-521 elliptic curve SPKI data")
+              })?;
+
+            if point.is_identity() {
+              return Err(data_error("invalid P-521 elliptic curve point"));
+            }
+
+            point.as_bytes().len()
+          }
         };
 
         if bytes_consumed != pk_info.subject_public_key.raw_bytes().len() {