ssh-key: introduce SkEd25519::new() constructor

ssh-key/src/public/sk.rs

@@ -132,6 +132,15 @@ pub struct SkEd25519 {
 }
 
 impl SkEd25519 {
+    /// Construct new instance of SkEd25519.
+    #[cfg(feature = "alloc")]
+    pub fn new(public_key: Ed25519PublicKey, application: impl Into<String>) -> Self {
+        SkEd25519 {
+            public_key: public_key,
+            application: application,
+        }
+    }
+
     /// Get the Ed25519 private key for this security key.
     pub fn public_key(&self) -> &Ed25519PublicKey {
         &self.public_key

ssh-key/tests/public_key.rs

@@ -3,7 +3,7 @@
 use hex_literal::hex;
 use sec1::consts::U32;
 use ssh_key::{Algorithm, PublicKey};
-use ssh_key::public::SkEcdsaSha2NistP256;
+use ssh_key::public::{Ed25519PublicKey, SkEcdsaSha2NistP256, SkEd25519};
 use std::collections::HashSet;
 
 #[cfg(feature = "ecdsa")]
@@ -346,6 +346,25 @@ fn decode_sk_ed25519_openssh() {
     );
 }
 
+#[test]
+fn new_sk_ed25519_openssh() {
+    const EXAMPLE_PUBKEY: Ed25519PublicKey = Ed25519PublicKey {0: [
+        0x21, 0x68, 0xfe, 0x4e, 0x4b, 0x53, 0xcf, 0x3a,
+        0xde, 0xee, 0xba, 0x60, 0x2f, 0x5e, 0x50, 0xed,
+        0xb5, 0xef, 0x44, 0x1d, 0xba, 0x88, 0x4f, 0x51,
+        0x19, 0x10, 0x9d, 0xb2, 0xda, 0xfd, 0xd7, 0x33,
+    ]};
+
+    let sk_key = SkEd25519::new(EXAMPLE_PUBKEY, "ssh:".to_string());
+    let key = PublicKey::from_openssh(OPENSSH_SK_ED25519_EXAMPLE).unwrap();
+
+    let ed25519_key = key.key_data().sk_ed25519().unwrap();
+    assert_eq!(
+        &sk_key,
+        ed25519_key
+    );
+}
+
 #[cfg(all(feature = "alloc"))]
 #[test]
 fn decode_custom_algorithm_openssh() {