Password validation in UITextField in iOS

Question

I have 1 UITextfield for password in my iPhone application.

I want to validate this textfield with the following validation.

• Must be at le

Answer 1

Condition: Password should contain atleast 8 characters, 1 uppercase and 1 number

Solution in Swift 3

you can write String Extension like this,

extension String {
    func isValidPassword() -> Bool {
        let regularExpression = "^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)(?=.*[$@$!%*?&])[A-Za-z\\d$@$!%*?&]{8,}"
        let passwordValidation = NSPredicate.init(format: "SELF MATCHES %@", regularExpression)

        return passwordValidation.evaluate(with: self)
    }
}

//Example 1

var password = "@Abcdef011" //string from UITextField (Password)
password.isValidPassword() // -> true

//Example 2

var password = "Abcdef011" //string from UITextField 
password.isValidPassword() // -> false

or you can write function like this,

func validate(password: String) -> Bool
{
    let regularExpression = "^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)(?=.*[$@$!%*?&])[A-Za-z\\d$@$!%*?&]{8,}"

    let passwordValidation = NSPredicate.init(format: "SELF MATCHES %@", regularExpression)

    return passwordValidation.evaluate(with: password)
}

this will give you the same result.

Answer 2

Swift 3

check if password is strong ?

1. length more than or equal 8
2. lowercase
3. uppercase
4. decimal Digits

5. special characters like !@#$%^&*()_-+ is optional

   Why i not use regular expression ?

   Because it's difficult to support reserved characters in regular expression syntax.

---

 func isValidated(_ password: String) -> Bool {
     var lowerCaseLetter: Bool = false
     var upperCaseLetter: Bool = false
     var digit: Bool = false
     var specialCharacter: Bool = false

     if password.characters.count  >= 8 {
         for char in password.unicodeScalars {
             if !lowerCaseLetter {
                 lowerCaseLetter = CharacterSet.lowercaseLetters.contains(char)
             }
             if !upperCaseLetter {
                 upperCaseLetter = CharacterSet.uppercaseLetters.contains(char)
             }
             if !digit {
                 digit = CharacterSet.decimalDigits.contains(char)
             }
             if !specialCharacter {
                 specialCharacter = CharacterSet.punctuationCharacters.contains(char)
             }
         }
         if specialCharacter || (digit && lowerCaseLetter && upperCaseLetter) {
             //do what u want
             return true
         }
         else {
             return false
         }
     }
     return false
 }
 let isVaildPass:Bool = isValidated("Test**00+-")
 print(isVaildPass)

Answer 3

I have this elegant solution for Forms (like sign-up) where you have a lot of validation

I have in my custom UITextField the outlet:

@IBInspectable var regexpValidation: String? = nil

In storyboard I can access it through attribute inspector and put regexp string like that (for email):

[a-z0-9!#$%&'*+/=?^_{|}~-]+(?:.[a-z0-9!#$%&'*+/=?^_{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?

then in my subclass I have this computed var:

@IBInspectable var regexpValidation: String? = nil // Optional, Set this in InterfaceBuilder

var inputIsValid: Bool {
    get {
        if let expr = regexpValidation {
           return (text.rangeOfString(expr, options: NSStringCompareOptions.RegularExpressionSearch, range: nil, locale: nil) != nil)
        } else {
            return true
        }

    }
}

which could be used like this:

   override func resignFirstResponder() -> Bool {
        if (inputIsValid) {
            return super.resignFirstResponder()
        }
        else {
            text = ""
            return false
        }
    }

Answer 4

for me Best way was to use NSPredicate and regex. this is regex for your case: ^(?=.{10,})(?=.*[0-9])(?=.*[a-zA-Z])([@#$%^&=a-zA-Z0-9_-]+)$

objective C code:

NSString *regex = @"^(?=.{10,})(?=.*[0-9])(?=.*[a-zA-Z])([@#$%^&=a-zA-Z0-9_-]+)$";

NSPredicate *passwordTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];

BOOL isValid = [passwordTest evaluateWithObject:yourTextfield.text];

Answer 5

You can also do this by using Regex. Here are few example I am providing for you:

// *** Validation for Password ***

    // "^(?=.*[A-Za-z])(?=.*\\d)[A-Za-z\\d]{8,}$" --> (Minimum 8 characters at least 1 Alphabet and 1 Number)
    // "^(?=.*[A-Za-z])(?=.*\\d)(?=.*[$@$!%*#?&])[A-Za-z\\d$@$!%*#?&]{8,16}$" --> (Minimum 8 and Maximum 16 characters at least 1 Alphabet, 1 Number and 1 Special Character)
    // "^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)[a-zA-Z\\d]{8,}$" --> (Minimum 8 characters at least 1 Uppercase Alphabet, 1 Lowercase Alphabet and 1 Number)
    // "^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)(?=.*[$@$!%*?&])[A-Za-z\\d$@$!%*?&]{8,}" --> (Minimum 8 characters at least 1 Uppercase Alphabet, 1 Lowercase Alphabet, 1 Number and 1 Special Character)
    // "^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)(?=.*[$@$!%*?&])[A-Za-z\\d$@$!%*?&]{8,10}" --> (Minimum 8 and Maximum 10 characters at least 1 Uppercase Alphabet, 1 Lowercase Alphabet, 1 Number and 1 Special Character)

Fourth from the list is your case, following code snippet shows how to use it:

-(BOOL)isValidPassword:(NSString *)passwordString
{
    NSString *stricterFilterString = @"^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)(?=.*[$@$!%*?&])[A-Za-z\\d$@$!%*?&]{10,}";
    NSPredicate *passwordTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", stricterFilterString];
    return [passwordTest evaluateWithObject:passwordString];
}

Using the method:

if(![self isValidPassword:txtPassword.text]) {
    /* Show alert: "Password must be minimum 10 characters,
       at least 1 Uppercase Alphabet, 1 Lowercase Alphabet, 
       1 Number and 1 Special Character" */
}
else {
    // Password is valid
}