Password strength policy

Stytch offers two different password strength strategies for you to choose from, zxcvbn and Lowercase Uppercase Digits Special Characters (LUDS). On top of these two strategies, we also offer breach detection, powered by HaveIBeenPwned to protect your users from password breaches.

You may choose any mix of these strategies for your Stytch Project. For example, you may choose to use LUDS for password complexity plus breach detection, or zxcvbn without breach detection.

By default, our Passwords product uses zxcvbn for password strength and automatically protects your users against password breaches. If that doesn't fit your needs, you may configure your desired strategy by contacting support@stytch.com.

Passwords at Stytch may contain any UTF8 character, e.g. spaces, emojis, non-English characters, etc. Any of these types of characters may contribute to fulfilling the complexity requirements you choose.

zxcvbn is a password strength estimation library developed originally by Dropbox. It is a complex password strength strategy that checks for the presence of dictionary words, common passwords, and common patterns. It does not explicitly check for lowercase letters, uppercase letters, digits, or special characters.

Some end users find zxcvbn to be too strict, and may be unable to create a password that meets the requirements. If you find that your users are unable to create a password that meets the requirements, you may want to consider using LUDS instead.

You can find examples of zxcvbn passwords and an interactive tool to test passwords at this hosted zxcvbn checker.

If a user provides a commonly used password like, "p@ssword1", the response from our Strength check endpoint will look like the following:

{
  "breach_detection_on_create": true,
  "breached_password": false,
  "feedback": {
    "luds_requirements": null,
    "suggestions": [
      "Add another word or two. Uncommon words are better.",
      "Predictable substitutions like '@' instead of 'a' don't help very much."
    ],
    "warning": "This is a top-100 common password."
  },
  "request_id": "request-id-test-86779128-d4e7-4dd4-a588-88faa570f638",
  "score": 0,
  "status_code": 200,
  "strength_policy": "zxcvbn",
  "valid_password": false
}

You may use the warning and suggestions fields to provide feedback directly to your users to help them craft a stronger password that will pass your requirements.

LUDS stands for Lowercase Uppercase Digits Special Characters. It is a simple password strength strategy that checks for the presence of lowercase letters, uppercase letters, digits, and special characters. It does not check for dictionary words or common passwords.

For this example, we will use the following password strength policy:

• Strength policy: LUDS
• LUDS minimum length: 8
• LUDS complexity: 4

If a user provides a password of, "Lorem1!", the password will be considered invalid. The password contains the necessary complexity, symbols, numbers, and upper and lower case letters, but is not of sufficient length. The response from our Strength check endpoint would look like the following:

{
	"breach_detection_on_create": true,
	"breached_password": false,
	"feedback": {
        "luds_requirements": {
            "has_digit": true,
            "has_lower_case": true,
            "has_symbol": true,
            "has_upper_case": true,
            "missing_characters": 2,
            "missing_complexity": 0
        },
		"suggestions": null,
		"warning": null
	},
	"request_id": "request-id-test-86779128-d4e7-4dd4-a588-88faa570f638",
	"score": 0,
	"status_code": 200,
	"strength_policy": "luds",
	"valid_password": false
}

You may use the missing_characters and missing_complexity fields to provide feedback to your users to help them craft a stronger password that will pass your requirements.

Stytch's Passwords product automatically protects your users against password breaches. We do this by checking the password against a list of known passwords that have been leaked in data breaches from HaveIBeenPwned. If the password is found in this list, we will reject the password and ask the user to choose a different one or reset their password if they have already used it previously.

Protecting your users against password breaches is a critical part of your security strategy. Password breaches are a common attack vector for hackers, and can be used to gain access to your users' accounts and compromise your app.

You may set or update the password strength policy for your Stytch Project via the Passwords tab in the Stytch Dashboard.

• Strength policy type: The type of password validation policy to use – either one of our default zxcvbn policies or a custom policy using LUDS.
• Minimum password length: When using a custom LUDS policy, the minimum number of characters required for a password. We require a minimum of at least 8 characters.
• Number of character types: When using a custom LUDS policy, the minimum number of character types required for a password. Allowable values are 1-4. This value determines how many LUDS checks must be passed – for example, 2 means that a password with a symbol and a number is valid because two of the four LUDS requirements are met. You cannot choose which LUDS requirements are required, only how many.
• Password strength enforcement during authentication: Determines whether or not password strength checks are applied during password authentication. During user migrations from another service with a password policy that is incompatible with Stytch's password strength policy options, you may choose to disable password strength checks during authentication.
• Breach detection: Determines whether passwords are checked against the HaveIBeenPwned dataset during password creation and authentication, during password creation only, or never.