Static vars for keytypes (#639)

* Static inits for keytype.

* Missed

Sources/Packages/Sources/SecretKit/KeychainTypes.swift

@@ -53,12 +53,12 @@ public extension SecretStore {
     ///   - secret: The secret which will be used for signing.
     /// - Returns: The appropriate algorithm.
     func signatureAlgorithm(for secret: SecretType) -> SecKeyAlgorithm? {
-        switch (secret.keyType.algorithm, secret.keyType.size) {
-        case (.ecdsa, 256):
+        switch secret.keyType {
+        case .ecdsa256:
             .ecdsaSignatureMessageX962SHA256
-        case (.ecdsa, 384):
+        case .ecdsa384:
             .ecdsaSignatureMessageX962SHA384
-        case (.rsa, 2048):
+        case .rsa2048:
             .rsaSignatureMessagePKCS1v15SHA512
         default:
             nil

Sources/Packages/Sources/SecretKit/OpenSSH/OpenSSHPublicKeyWriter.swift

@@ -75,16 +75,16 @@ extension OpenSSHPublicKeyWriter {
     ///   - length: The key length of the algorithm.
     /// - Returns: The OpenSSH identifier for the algorithm.
     public func openSSHIdentifier(for keyType: KeyType) -> String {
-        switch (keyType.algorithm, keyType.size) {
-        case (.ecdsa, 256):
+        switch keyType {
+        case .ecdsa256:
             "ecdsa-sha2-nistp256"
-        case (.ecdsa, 384):
+        case .ecdsa384:
             "ecdsa-sha2-nistp384"
-        case (.mldsa, 65):
+        case .mldsa65:
             "ssh-mldsa-65"
-        case (.mldsa, 87):
+        case .mldsa87:
             "ssh-mldsa-87"
-        case (.rsa, _):
+        case .rsa2048:
             "ssh-rsa"
         default:
             "unknown"
@@ -101,8 +101,7 @@ extension OpenSSHPublicKeyWriter {
         // [4 byte prefix][2 byte prefix][n][2 byte prefix][e]
         // Rather than parse out the whole ASN.1 blob, we'll cheat and pull values directly since
         // we only support one key type, and the keychain always gives it in a specific format.
-        let keySize = secret.keyType.size
-        guard secret.keyType.algorithm == .rsa && keySize == 2048 else { fatalError() }
+        guard secret.keyType == .rsa2048 else { fatalError() }
         let length = secret.keyType.size/8
         let data = secret.publicKey
         let n = Data(data[8..<(9+length)])

Sources/Packages/Sources/SecretKit/Types/Secret.swift

@@ -32,7 +32,13 @@ public extension Secret {
 
 /// The type of algorithm the Secret uses.
 public struct KeyType: Hashable, Sendable, Codable, CustomStringConvertible {
-    
+
+    public static let ecdsa256 = KeyType(algorithm: .ecdsa, size: 256)
+    public static let ecdsa384 = KeyType(algorithm: .ecdsa, size: 384)
+    public static let mldsa65 = KeyType(algorithm: .mldsa, size: 65)
+    public static let mldsa87 = KeyType(algorithm: .mldsa, size: 87)
+    public static let rsa2048 = KeyType(algorithm: .rsa, size: 2048)
+
     public enum Algorithm: Hashable, Sendable, Codable {
         case ecdsa
         case mldsa
@@ -41,7 +47,7 @@ public struct KeyType: Hashable, Sendable, Codable, CustomStringConvertible {
 
     public var algorithm: Algorithm
     public var size: Int
-    
+
     public init(algorithm: Algorithm, size: Int) {
         self.algorithm = algorithm
         self.size = size