one more condition should not start with a digit how can i do this? An example: where 6 and 20 are minimum and maximum length for the password. What's the etiquette for addressing a friend's partner or family in a greeting card? I think it would be easier to break your regex down and do it one bit at a time. Learn to dig a level deeper. Regular Expression for alphanumeric and underscores. Is the character set ASCII or Unicode, or ?? Although the resulted regex may not be most optimal, it will be easier to maintain and/or change, and the user will have a better control over the result. Use a nonbacktracking expression to match the whole password first, if it has at least 8 characters (this way, there is no combinatorial explosion for long, but invalid passwords): Use lookbehind assertions to check for presence of all required characters (AND-conditions). Regex for password must contain at least eight characters, at least one number and both lower and uppercase letters and special characters, How to use Regular Expressions (Regex) in Microsoft Excel both in-cell and loops. Strong passwords should not contain personal information. I'm using this template (?=(?:.*? How can I perform validation on a secure password. Validate a username and password against Active Directory? Stack Overflow for Teams is a private, secure spot for you and In your life as a programmer you will asked to do many things that do not make sense. Extended the immediate above, much less so. As an example how this could be done with a readable/maintainable regex. The question (if it mentioned regular expressions) is wrong. @w0lf: I could not agree more. Is: Chocolate "C" is upper case and the rest is lower case :) The last column shows how the simple password is converted into one that is harder to figure out. Make your password at least 30,000 times stronger by using a combination of mixed-case letters, numbers and special characters compared to a password consisting of only lowercase letters. Questions: I want a regular expression to check that a password must be eight characters including one uppercase letter, one special character and alphanumeric characters. In simple words the position of checking resets to the original position after each condition of lookahead is met. On CPU-wise string operations for checking the criteria/validation is much cheaper and faster than regex! 839. Do far-right parties get a disproportionate amount of media coverage, and why? The table below shows examples of a simple password that is progressively made more complex. On the example above it is missing a Capital Letter and a symbol(*&^..etc). One trick that is not suggested is replacing characters with common number and special character replacements in dictionary words, like this: tr1ck0rteat. a password must be eight characters including one uppercase letter, one special character and alphanumeric characters. Regular expression to check if password is “8 characters including 1 uppercase letter, 1 special character, alphanumeric characters” (7) As an example how this could be done with a readable/maintainable regex. If anything matches that, then it's an invalid password. If you need only one upper case and special character then this should work: The regular expression you was looking for is: /^(?=.*[a-z])(?=.*[A-Z])(?=.*[0-9])(?=.*[! It might take a bit more to do, but I am pretty sure that maintaining it and debugging it would be easier. Lowercase and upper case letters refer to how a letter is written - as a capital letter ("A" for example) or as a small, lowercase, letter ("a" for example). This means that, for example, typing the letter B is not the same as typing the letter b and will result in your password being rejected if … Pseudocode (been switching between too many languages, of late): Bet you read and understood the above code almost instantly. The more people you work with, the more code needs to be readable although some regexp implementation I saw as answers are quite clear. Are broiler chickens injected with hormones in their left legs? While this code snippet may solve the problem, it doesn't explain why or how it answers the question. Best is not using regex for everything. To type in uppercase, you can use either the Caps Lock key or the Shift key on the keyboard. To ensure you are matching entire input string, you can enclose the regex between, If the OP wanted exactly 8 characters, so you'd need to add. I agree. Why did the apple explode when spun very fast? Why was the name of Discovery's most recent episode "Unification III"? Those requirements are very light. By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Service. I would recommend that you break it down like I have specified. For example, a, b, and c is lowercase, and A, B, and C is uppercase. Lowercase and upper case letters refer to how a letter is written - as a capital letter ("A" for example) or as a small, lowercase, letter ("a" for example). The first column lists simple words that are easy to remember and are found in the dictionary. Learning to know when the question is wrong is massively more important than clever answers. @ShilpiJaiswal Either you are using a flag for case-insensitive match, or making a "find" instead of "match". anything with less than 8 characters OR anything with no numbers OR anything with no uppercase OR anything with no special characters.