Class PasswordGenerator

java.lang.Object
de.gustavblass.commons.crypto.PasswordGenerator
public class PasswordGenerator extends Object
A class that generates secure passwords and passphrases. It uses the EFF word list to generate password, which are easy to remember and type, but not as secure as random passwords. The strength of a password can be estimated with the estimatePasswordStrength(char[]) method, which uses the Zxcvbn library.

  • Field Details

    • LOG

      private static final org.apache.logging.log4j.Logger LOG

    • EFF_WORD_LIST

      @NonNull private static final @NonNull List<String> EFF_WORD_LIST
      The EFF word list, a list of 7776 words that can be used to generate passphrases. See EFF word list.

  • Constructor Details

    • PasswordGenerator

      public PasswordGenerator() throws de.gustavblass.commons.exceptions.IllegalStateException
      Loads the EFF word list from the resources. The EFF word list is a list of 7776 words that can be used to generate passphrases. Without it, the generatePassphrase() method will not work.
      Throws:
      de.gustavblass.commons.exceptions.IllegalStateException - If the EFF word list could not be loaded.

  • Method Details

    • generatePassphrase

      public char[] generatePassphrase() throws de.gustavblass.commons.exceptions.IllegalStateException
      Generates a securely random passphrase consisting of 6 words from the EFF word list. The strength of the passphrase is not too high if the attacker knows that it only consists of natural language words. However, it is easy to remember and type, which is why it is suitable for some use cases, e.g. when the user does not have a password manager available.
      Returns:
      A passphrase consisting of 6 words from the EFF word list.
      Throws:
      de.gustavblass.commons.exceptions.IllegalStateException - Should not happen. If it does, it means that the EFF word list could not be loaded.

    • estimatePasswordStrength

      @NonNull public static @NonNull PasswordGenerator.PasswordStrength estimatePasswordStrength(char[] password)
      Uses the Zxcvbn library to check how hard the given passsword is to guess.
      Parameters:
      password - The password to estimate the strength of.
      Returns:
      The estimated strength of the password, according to Zxcvbn.