- re-add private key base58 init needed for torus

Sources/KukaiCryptoSwift/PrivateKey.swift

@@ -47,6 +47,27 @@ public struct PrivateKey: Codable {
 		self.signingCurve = signingCurve
 	}
 
+	/**
+	 Initialize a key with the given base58check encoded string.
+	 - parameter string: A base58check encoded string.
+	 - parameter signingCurve: The elliptical curve to use for the key. Defaults to ed25519.
+	 */
+	public init?(_ string: String, signingCurve: EllipticalCurve = .ed25519) {
+		switch signingCurve {
+			case .ed25519:
+				guard let bytes = Base58Check.decode(string: string, prefix: Prefix.Keys.Ed25519.secret) else {
+					return nil
+				}
+				self.init(bytes)
+
+			case .secp256k1:
+				guard let bytes = Base58Check.decode(string: string, prefix: Prefix.Keys.Secp256k1.secret) else {
+					return nil
+				}
+				self.init(bytes, signingCurve: .secp256k1)
+		}
+	}
+
 
 
 	// MARK: - Utils