Password validation in UITextField in iOS 10 --> Objective C - ios

Question

I'm having 1 UITextfield for password in my iPhone application.
I want to validate this textfield with the following validation.
Must be at least 6 characters
Must contain at least one english letter, one digit and Remaining all
special characters are make as optional (ie not mandetory)
how can I restrict the UITextField with above requirements. please anyone help me out to do this..

Answer 1

Use this method to validate your password:
-(BOOL) isPasswordValid:(NSString *)password {
NSCharacterSet *upperCaseChars = [NSCharacterSet characterSetWithCharactersInString:#"ABCDEFGHIJKLKMNOPQRSTUVWXYZ"];
NSCharacterSet *lowerCaseChars = [NSCharacterSet characterSetWithCharactersInString:#"abcdefghijklmnopqrstuvwxyz"];
//NSCharacterSet *numbers = [NSCharacterSet characterSetWithCharactersInString:#"0123456789"];
if ( [password length]<7 )
return NO; //too short
NSRange range;
range = [password rangeOfCharacterFromSet:[NSCharacterSet letterCharacterSet]];
if ( !range.length )
return NO; // no letter
range = [password rangeOfCharacterFromSet:[NSCharacterSet decimalDigitCharacterSet]];
if ( !range.length )
return NO; // no number;
range = [password rangeOfCharacterFromSet:upperCaseChars];
if ( !range.length )
return NO; // no uppercase letter;
range = [password rangeOfCharacterFromSet:lowerCaseChars];
if ( !range.length )
return NO; // no lowerCase Chars;
return YES;
}

Answer 2

Below is what I use using RegEx
NSString *passwordRegex = #"^.*(?=.{6,})(?=.*\\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[##$!&]).*$";
NSPredicate *passwordTest = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", passwordRegex];
if (![passwordTest evaluateWithObject:passwordTF.text]) {
// Password must be at least 6 character, containing lowercase letter, one uppercase letter, digits, and special character (!##$&)
}

Answer 3

Try this :
-(BOOL)isValidPasswordWithText:(UITextField *)textfield{
NSString *regex1 = #"^(?=.*[A-Za-z])(?=.*\\d)[A-Za-z\\d$#$!%*#?&]{6,}$";
NSPredicate *test1 = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", regex1];
return [test1 evaluateWithObject:textfield.text] ;
}

Answer 4

Inspired by Vamshi Krishna's answer, I think it could be more simple.
The decimalDigitCharacterSet can match any digital characters. Since the OP's intention didn't mention the upper case issue, so the letterCharacterSet should be enough here.
FYI:
BOOL ValidatePassword(NSString *candidate)
{
if (candidate.length < 6) {
return NO;
}
BOOL foundLetter = [candidate rangeOfCharacterFromSet:NSCharacterSet.letterCharacterSet].location != NSNotFound;
BOOL foundDigit = [candidate rangeOfCharacterFromSet:NSCharacterSet.decimalDigitCharacterSet].location != NSNotFound;
return foundLetter && foundDigit;
}