Module: Sysrandom

Defined in:
lib/sysrandom.rb,
lib/sysrandom/version.rb,
ext/sysrandom/sysrandom_ext.c

Overview

Secure random number generation using system RNG facilities

Constant Summary collapse

DEFAULT_LENGTH =

For some reason SecureRandom defaults to 16 bytes

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VERSION = 
"1.0.4".freeze

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.__random_uint32 ⇒ Object 



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# File 'ext/sysrandom/sysrandom_ext.c', line 9

static VALUE Sysrandom_random_uint32(VALUE self);

.base64(n = nil) ⇒ Object 



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# File 'lib/sysrandom.rb', line 53

def base64(n = nil)
  Base64.encode64(random_bytes(n)).chomp
end

.hex(n = nil) ⇒ Object 



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# File 'lib/sysrandom.rb', line 62

def hex(n = nil)
  random_bytes(n).unpack("h*").first
end

.random_bytes ⇒ Object 



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# File 'ext/sysrandom/sysrandom_ext.c', line 10

static VALUE Sysrandom_random_bytes(int argc, VALUE *argv, VALUE self);

.random_number(n = 0) ⇒ Object 



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# File 'lib/sysrandom.rb', line 42

def random_number(n = 0)
  result = __random_uint32 / (2**32).to_f

  if n <= 0
    result
  else
    result *= n
    n.is_a?(Fixnum) ? result.floor : result
  end
end

.urlsafe_base64(n = nil, padding = false) ⇒ Object 



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# File 'lib/sysrandom.rb', line 57

def urlsafe_base64(n = nil, padding = false)
  result = Base64.urlsafe_encode64(random_bytes(n)).chomp
  padding ? result : result.tr("=", "")
end

.uuid ⇒ Object 



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# File 'lib/sysrandom.rb', line 66

def uuid
  values = hex(16).match(/\A(.{8})(.{4})(.)(.{3})(.)(.{3})(.{12})\z/)
  "#{values[1]}-#{values[2]}-4#{values[4]}-#{'89ab'[values[5].ord % 4]}#{values[6]}-#{values[7]}"
end

Instance Method Details

#__random_uint32 ⇒ Object

Random uint32, used by random_number. The C extension provides an equivalent method



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# File 'lib/sysrandom.rb', line 25

def __random_uint32
  @_java_secure_random.nextLong & 0xFFFFFFFF
end

#random_bytes(n = nil) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'ext/sysrandom/sysrandom_ext.c', line 10

def random_bytes(n = nil)
  n ||= DEFAULT_LENGTH
  raise ArgumentError, "negative string size" if n < 0
  return "" if n == 0

  bytes = Java::byte[n].new
  @_java_secure_random.nextBytes(bytes)
  String.from_java_bytes(bytes)
end