ActiveSupport::SecureRandom

Files

Description

Secure random number generator interface.

This library is an interface for secure random number generator which is suitable for generating session key in HTTP cookies, etc.

It supports following secure random number generators.

  • openssl
  • /dev/urandom
  • Win32

Note: This module is based on the SecureRandom library from Ruby 1.9, revision 18786, August 23 2008. It‘s 100% interface-compatible with Ruby 1.9‘s SecureRandom library.

Example

 # random hexadecimal string.
 p SecureRandom.hex(10) #=> "52750b30ffbc7de3b362"
 p SecureRandom.hex(10) #=> "92b15d6c8dc4beb5f559"
 p SecureRandom.hex(11) #=> "6aca1b5c58e4863e6b81b8"
 p SecureRandom.hex(12) #=> "94b2fff3e7fd9b9c391a2306"
 p SecureRandom.hex(13) #=> "39b290146bea6ce975c37cfc23"
 ...

 # random base64 string.
 p SecureRandom.base64(10) #=> "EcmTPZwWRAozdA=="
 p SecureRandom.base64(10) #=> "9b0nsevdwNuM/w=="
 p SecureRandom.base64(10) #=> "KO1nIU+p9DKxGg=="
 p SecureRandom.base64(11) #=> "l7XEiFja+8EKEtY="
 p SecureRandom.base64(12) #=> "7kJSM/MzBJI+75j8"
 p SecureRandom.base64(13) #=> "vKLJ0tXBHqQOuIcSIg=="
 ...

 # random binary string.
 p SecureRandom.random_bytes(10) #=> "\016\t{\370g\310pbr\301"
 p SecureRandom.random_bytes(10) #=> "\323U\030TO\234\357\020\a\337"
 ...

Methods

Public Class methods

base64 (n=nil)

SecureRandom.base64 generates a random base64 string.

The argument n specifies the length of the random length. The length of the result string is about 4/3 of n.

If n is not specified, 16 is assumed. It may be larger in future.

If secure random number generator is not available, NotImplementedError is raised.

hex (n=nil)

SecureRandom.hex generates a random hex string.

The argument n specifies the length of the random length. The length of the result string is twice of n.

If n is not specified, 16 is assumed. It may be larger in future.

If secure random number generator is not available, NotImplementedError is raised.

random_bytes (n=nil)

SecureRandom.random_bytes generates a random binary string.

The argument n specifies the length of the result string.

If n is not specified, 16 is assumed. It may be larger in future.

If secure random number generator is not available, NotImplementedError is raised.

random_number (n=0)

SecureRandom.random_number generates a random number.

If an positive integer is given as n, SecureRandom.random_number returns an integer: 0 <= SecureRandom.random_number(n) < n.

If 0 is given or an argument is not given, SecureRandom.random_number returns an float: 0.0 <= SecureRandom.random_number() < 1.0.