Added conversion from hex string to hex array for the private key.

Trust/EtherClient/EtherKeystore.swift

@@ -207,7 +207,7 @@ class EtherKeystore: Keystore {
     }
 
     func convertPrivateKeyToKeystoreFile(privateKey: String) -> Result<[String: Any], KeyStoreError> {
-        let password: [UInt8] = Array(privateKey.utf8)
+        let password: [UInt8] = Array(Data(fromHexEncodedString: privateKey)!)
         let numberOfIterations = 262144
         do {
             // derive key
@@ -268,3 +268,37 @@ extension Account {
         )
     }
 }
+
+extension Data {
+    init?(fromHexEncodedString string: String) {
+        // Convert 0 ... 9, a ... f, A ...F to their decimal value,
+        // return nil for all other input characters
+        func decodeNibble(u: UInt16) -> UInt8? {
+            switch(u) {
+            case 0x30 ... 0x39:
+                return UInt8(u - 0x30)
+            case 0x41 ... 0x46:
+                return UInt8(u - 0x41 + 10)
+            case 0x61 ... 0x66:
+                return UInt8(u - 0x61 + 10)
+            default:
+                return nil
+            }
+        }
+        
+        self.init(capacity: string.utf16.count/2)
+        var even = true
+        var byte: UInt8 = 0
+        for c in string.utf16 {
+            guard let val = decodeNibble(u: c) else { return nil }
+            if even {
+                byte = val << 4
+            } else {
+                byte += val
+                self.append(byte)
+            }
+            even = !even
+        }
+        guard even else { return nil }
+    }
+}