ssh-key: introduce SkEcdsaSha2NistP256::new() constructor

ssh-key/src/public/sk.rs

@@ -30,6 +30,15 @@ pub struct SkEcdsaSha2NistP256 {
 
 #[cfg(feature = "ecdsa")]
 impl SkEcdsaSha2NistP256 {
+    /// Construct new instance of SkEcdsaSha2NistP256.
+    #[cfg(feature = "alloc")]
+    pub fn new(ec_point: EcdsaNistP256PublicKey, application: impl Into<String>) -> Self {
+        SkEcdsaSha2NistP256 {
+            ec_point: ec_point,
+            application: application,
+        }
+    }
+
     /// Get the elliptic curve point for this Security Key.
     pub fn ec_point(&self) -> &EcdsaNistP256PublicKey {
         &self.ec_point

ssh-key/tests/public_key.rs

@@ -1,7 +1,9 @@
 //! SSH public key tests.
 
 use hex_literal::hex;
+use sec1::consts::U32;
 use ssh_key::{Algorithm, PublicKey};
+use ssh_key::public::SkEcdsaSha2NistP256;
 use std::collections::HashSet;
 
 #[cfg(feature = "ecdsa")]
@@ -296,6 +298,32 @@ fn decode_sk_ecdsa_p256_openssh() {
     );
 }
 
+#[cfg(feature = "ecdsa")]
+#[test]
+fn new_sk_ecdsa_p256() {
+    const EXAMPLE_EC_POINT: [u8; 65] = [
+        0x04, 0x81, 0x0b, 0x40, 0x9d, 0x83, 0x82, 0xf6,
+        0x97, 0xd7, 0x24, 0x25, 0x28, 0x5a, 0x24, 0x7d,
+        0x63, 0x36, 0xb2, 0xeb, 0x9a, 0x08, 0x52, 0x36,
+        0xaa, 0x9d, 0x1e, 0x26, 0x87, 0x47, 0xca, 0x0e,
+        0x8e, 0xe2, 0x27, 0xf1, 0x73, 0x75, 0xe9, 0x44,
+        0xa7, 0x75, 0x39, 0x2f, 0x1d, 0x35, 0x84, 0x2d,
+        0x13, 0xf6, 0x23, 0x75, 0x74, 0xab, 0x03, 0xe0,
+        0x0e, 0x9c, 0xc1, 0x79, 0x9e, 0xcd, 0x8d, 0x93,
+        0x1e,
+    ];
+
+    let ec_point = sec1::EncodedPoint::<U32>::from_bytes(&EXAMPLE_EC_POINT).unwrap();
+    let sk_key = SkEcdsaSha2NistP256::new(ec_point, "ssh:".to_string());
+    let key = PublicKey::from_openssh(OPENSSH_SK_ECDSA_P256_EXAMPLE).unwrap();
+
+    let ecdsa_key = key.key_data().sk_ecdsa_p256().unwrap();
+    assert_eq!(
+        &sk_key,
+        ecdsa_key
+    );
+}
+
 #[test]
 fn decode_sk_ed25519_openssh() {
     let key = PublicKey::from_openssh(OPENSSH_SK_ED25519_EXAMPLE).unwrap();