     /// - parameter password: Password string to be calculated
     ///
     /// - returns: Level of strength in NJOPasswordStrength
-    open class func strength(of password: String) -> NJOPasswordStrength {
-        return NJOPasswordStrength(for: NJOEntropy(for: password))
+    open static func strength(ofPassword password: String) -> PasswordStrength {
+        return passwordStrength(forEntropy: entropy(of: password))
     }
 
     /// Converts NJOPasswordStrength to localized string.

    /// - parameter strength: NJOPasswordStrength to be converted
    ///
    /// - returns: Localized string
    open class func localizedString(for strength: NJOPasswordStrength) -> String {
        switch strength {
        case .veryWeak:
            return NSLocalizedString("NAVAJO_VERY_WEAK", tableName: nil, bundle: Bundle.main, value: "Very Weak", comment: "Navajo - Very weak")

        return log2f(sizeOfCharacterSet) * Float(string.characters.count)
    }

    private static func passwordStrength(forEntropy entropy: Float) -> PasswordStrength {
        if entropy < 28 {
            return .veryWeak
        } else if entropy < 36 {
