Password must have at least one character without alpha

Question

I need a regex for the password. Password must contain at least 8 characters. At least one character must be a number or a special character (not a letter).

[StringLength(100, ErrorMessage = "The {0} must be at least {2} characters long.", MinimumLength = 8)] [RegularExpression(@"(?=.*\W)?(?=.*\d)", ErrorMessage = "Error message")] [DataType(DataType.Password)] [Display(Name = "Password")] public string Password { get; set; } 

I have a length check, but I need help with a regular expression that checks if the password contains at least one number or a special character.

Valid passwords examples:

 testtest85* testtes* testtes1 test1234*+ 

Examples of invalid passwords:

 testtest testabc 

Answer 1

Use regex pattern ^(?=.{8})(?=.*[^a-zA-Z])

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Explanation:

 ^(?=.{8})(?=.*[^a-zA-Z]) │└──┬───┘└──────┬──────┘ │ │ │ │ │ └ string contains some non-letter character │ │ │ └ string contains at least 8 characters │ └ begining of line/string 

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If you want to limit also the maximum length (say 16), use a regex pattern:

 ^(?=.{8,16}$)(?=.*[^a-zA-Z]) 

Answer 2

Run it through a fairly simple regular expression: [^a-zA-Z]

And then check the length separately:

 if(string.Length > 7) 

Answer 3

A simple method would be:

 Match match1 = Regex.Match(<input_string>, @"(?=.{7})"); 

match1.Success guarantees that there are at least 8 characters.

 Match match2 = Regex.Match(<input_string>, [^a-zA-Z]); 

match2.Success ensures that there is at least one special character or number in the string.

 So, match1.Success && match2.Success guarantees will get what you want. 

Answer 4

I tried the Omega example, but it did not work with my C # code. I recommend using this instead:

 [RegularExpression(@"^(?=[^\d_].*?\d)\w(\w|[ !@ #$%]){7,20}", ErrorMessage = @"Error. Password must have one capital, one special character and one numerical character. It can not start with a special character or a digit.")] 

Answer 5

An expression like:

 [a-zA-Z]*[0-9\+\*][a-zA-Z0-9\+\*]* 

should work fine (obviously, insert any additional special characters you want to allow or use the ^ operator to match anything other than letters / numbers); no need to use complex images. This approach makes sense if you only want to allow a specific subset of special characters that you know are “safe” and prohibit everyone else.

If you want to include all special characters except certain ones that you know are “unsafe,” then it makes sense to use something like:

 \w[^\\]*[^a-zA-Z\\][^\\]* 

In this case, you explicitly prohibit the backslash in your password and allow any combination with at least one non-alphabetic character.

The above expression will match any string containing letters and at least one number or +, *. Regarding the requirement of “length 8”, there really is no reason to verify that using regular expression.

Answer 6

  function randomPassword(length) { var chars = "abcdefghijklmnopqrstuvwxyz#$%ABCDEFGHIJKLMNOP1234567890"; var pass = ""; for (var x = 0; x < length; x++) { var i = Math.floor(Math.random() * chars.length); pass += chars.charAt(i); } var pattern = false; var passwordpattern = new RegExp("[^a-zA-Z0-9+]+[0-9+]+[A-Z+]+[a-z+]"); pattern = passwordpattern.test(pass); if (pattern == true) { alert(pass); } else { randomPassword(length); } } 

try creating a random password with at least one special character