Feature #10849: Adding an alphanumeric function to SecureRandom

• Status: Closed
• Assignee: [e-mail] (Andrew Butterfield)
• Target version: -

[[e-mail] (Andrew Butterfield)]

It would be handy to have a method that produces a random alphanumeric string.

[[e-mail] (Andrew Butterfield)]

• File securerandom.txt securerandom.txt added

[[e-mail] (Andrew Butterfield)]

• File securerandom.patch securerandom.patch added

[nobu (Nobuyoshi Nakada)]

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

I don't like this interface.

  def self.choose(source, length)
    size = source.size
    length.times.map {source[random_number(size)]}.join('')
  end

  GRAPH = [*'!'..'~']
  def self.graph(length)
    choose(GRAPH, length)
  end

  ALPHANUMERIC = [*'A'..'Z', *'a'..'z', *'0'..'9']
  # SecureRandom.alphanumeric generates a random alphanumeric string.
  #
  # The argument _n_ specifies the length of the random number to be
  # generated.
  #
  # The result may contain A-Z, a-z and 0-9.
  #
  #   p SecureRandom.alphanumeric #=> "2BuBuLf3WfSKyQbRccA"
  #   p SecureRandom.alphanumeric #=> "6BbW0pxO0YENxn38HMUbcQ"
  #
  # If a secure random number generator is not available,
  # +NotImplementedError+ is raised.
  def self.alphanumeric(length)
    choose(ALPHANUMERIC, length)
  end

[[e-mail] (Andrew Butterfield)]

• File securerandom.patch securerandom.patch added
• File test_securerandom.patch test_securerandom.patch added

This is a fantastic interface and I really like the choose method.

[recursive-madman (Recursive Madman)]

Suggestion: Rename graph to printable and possibly add an :allow_space option?

[kosaki (Motohiro KOSAKI)]

This proposal doesn't contain a use-case nor proposal justification. So, nobody can judge this is good interface or not.

[f3ndot (Justin Bull)]

As an end user of Ruby, I'd like to be able to generate all sorts of cryptographically secure random characters. There's value in having only alphabetical or alphanumeric chars as they are slightly more human readable.

My use case is offline recovery codes that I expect individuals to write down.

[akr (Akira Tanaka)]

• Status changed from Open to Closed

Applied in changeset trunk|r60297.

---

SecureRandom.alphanumeric implemented.

[ruby-core:68098] [Feature #10849] proposed by Andrew Butterfield.

SecureRandom.choose and SecureRandom.graph is not included.
(The implementation has SecureRandom.choose but it is private.)

I feel the method name, SecureRandom.choose, doesn't represent
the behavior well.

The actual use cases of SecureRandom.graph is not obvious.

[nobu (Nobuyoshi Nakada)]

• Related to Feature #18183: make SecureRandom.choose public added