Explicit String as NSString

Sources/CryptoSwift/Foundation/AES+Foundation.swift

@@ -10,7 +10,7 @@ import Foundation
 
 extension AES {
     convenience public init(key:String, iv:String, blockMode:CipherBlockMode = .CBC) throws {
-        guard let kkey = key.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)?.arrayOfBytes(), let iiv = iv.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)?.arrayOfBytes() else {
+        guard let kkey = (key as NSString).dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)?.arrayOfBytes(), let iiv = (iv as NSString).dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)?.arrayOfBytes() else {
             throw Error.InvalidKeyOrInitializationVector
         }
         

Sources/CryptoSwift/Foundation/ChaCha20+Foundation.swift

@@ -10,7 +10,7 @@ import Foundation
 
 extension ChaCha20 {
     convenience public init?(key:String, iv:String) {
-        guard let kkey = key.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)?.arrayOfBytes(), let iiv = iv.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)?.arrayOfBytes() else {
+        guard let kkey = (key as NSString).dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)?.arrayOfBytes(), let iiv = (iv as NSString).dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)?.arrayOfBytes() else {
             return nil
         }
         self.init(key: kkey, iv: iiv)

Sources/CryptoSwift/Foundation/Rabbit+Foundation.swift

@@ -10,7 +10,7 @@ import Foundation
 
 extension Rabbit {
     convenience public init?(key: String) {
-        guard let kkey = key.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)?.arrayOfBytes() else {
+        guard let kkey = (key as NSString).dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)?.arrayOfBytes() else {
             return nil
         }
         self.init(key: kkey)
@@ -18,8 +18,8 @@ extension Rabbit {
     }
     
     convenience public init?(key: String, iv: String) {
-        guard let kkey = key.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)?.arrayOfBytes(),
-            let iiv = iv.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)?.arrayOfBytes()
+        guard let kkey = (key as NSString).dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)?.arrayOfBytes(),
+            let iiv = (iv as NSString).dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)?.arrayOfBytes()
             else {
                 return nil
         }