Secure string

This is a cryptographically secure random string generator based on


Create an instance with new SecureString():

SecureString secureString = new SecureString();

Then generate random strings with it:

String randomString = secureString.generate(length: 512);

The length defaults to 1024 if no length is specified.

Custom character lists

To specify a list of allowed characters, use the named parameter charList:

String randomBinaryString = secureString.generate(charList: ["0", "1"]);

The list defaults to hexadecimal characters (0-f).

Insecure string:

To create insecure random strings: use new SecureString(string: false) instead of new SecureString(). You can also specify a seed using new SecureString(string: false, seed: 2) (replacing 2 with your seed).


This library was made in spite of a library already existing due to two reasons:

  • That library did not have functionality for
  • That library was licensed under the BSD 3 clause license.