soveran / stringent

Generate a string with a target entropy

Stringent

Generate a string with a target entropy

Description

Stringent uses SecureRandom to generate a pseudo-random number with a target entropy, and proceeds to encode it with a given table of symbols. The target entropy defaults to 256 bits, and the table of symbols defaults to case sensitive alphanumeric characters. Both values can be passed as parameters.

The entropy parameter means that there are 2^entropy possible outputs for a given call. However, it does not mean that each bit is actually generated using one bit of entropy, since SecureRandom may use /dev/urandom which, while unguessable, may have less than 1 bit of entropy for each bit of output.

Usage

Generate a random string with the default values for target entropy and symbols table:

>> Stringent.generate
=> "kEPcWwph6OkyHIKZtw4DwnWnlJo0Q6QoDp8Iykshrfm"

Generate a random string with a custom target entropy:

>> Stringent.generate(entropy: 32)
=> "Kqd6e0"

Generate a random string with a custom target entropy and a custom table:

>> Stringent.generate(entropy: 16, table: "01")
=> "1000100110000000"

Installation

$ gem install stringent