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/Ruby 2.4

module Random::Formatter

Public Instance Methods

base64(n=nil) Show source

SecureRandom.base64 generates a random base64 string.

The argument n specifies the length, in bytes, of the random number to be generated. The length of the result string is about 4/3 of n.

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

The result may contain A-Z, a-z, 0-9, “+”, “/” and “=”.

p SecureRandom.base64 #=> "/2BuBuLf3+WfSKyQbRcc/A=="
p SecureRandom.base64 #=> "6BbW0pxO0YENxn38HMUbcQ=="

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

See RFC 3548 for the definition of base64.

# File lib/securerandom.rb, line 139
def base64(n=nil)
  [random_bytes(n)].pack("m0")
end
hex(n=nil) Show source

SecureRandom.hex generates a random hexadecimal string.

The argument n specifies the length, in bytes, of the random number to be generated. The length of the resulting hexadecimal string is twice of n.

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

The result may contain 0-9 and a-f.

p SecureRandom.hex #=> "eb693ec8252cd630102fd0d0fb7c3485"
p SecureRandom.hex #=> "91dc3bfb4de5b11d029d376634589b61"

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

# File lib/securerandom.rb, line 118
def hex(n=nil)
  random_bytes(n).unpack("H*")[0]
end
rand(*args) Show source
static VALUE
rand_random_number(int argc, VALUE *argv, VALUE obj)
{
    rb_random_t *rnd = try_get_rnd(obj);
    VALUE v = rand_random(argc, argv, obj, rnd);
    if (NIL_P(v)) v = rand_random(0, 0, obj, rnd);
    else if (!v) invalid_argument(argv[0]);
    return v;
}
random_bytes(n=nil) Show source

SecureRandom.random_bytes generates a random binary string.

The argument n specifies the length of the result string.

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

The result may contain any byte: “x00” - “xff”.

p SecureRandom.random_bytes #=> "\xD8\\\xE0\xF4\r\xB2\xFC*WM\xFF\x83\x18\xF45\xB6"
p SecureRandom.random_bytes #=> "m\xDC\xFC/\a\x00Uf\xB2\xB2P\xBD\xFF6S\x97"

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

# File lib/securerandom.rb, line 98
def random_bytes(n=nil)
  n = n ? n.to_int : 16
  gen_random(n)
end
random_number(*args) Show source
static VALUE
rand_random_number(int argc, VALUE *argv, VALUE obj)
{
    rb_random_t *rnd = try_get_rnd(obj);
    VALUE v = rand_random(argc, argv, obj, rnd);
    if (NIL_P(v)) v = rand_random(0, 0, obj, rnd);
    else if (!v) invalid_argument(argv[0]);
    return v;
}
urlsafe_base64(n=nil, padding=false) Show source

SecureRandom.urlsafe_base64 generates a random URL-safe base64 string.

The argument n specifies the length, in bytes, of the random number to be generated. The length of the result string is about 4/3 of n.

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

The boolean argument padding specifies the padding. If it is false or nil, padding is not generated. Otherwise padding is generated. By default, padding is not generated because “=” may be used as a URL delimiter.

The result may contain A-Z, a-z, 0-9, “-” and “_”. “=” is also used if padding is true.

p SecureRandom.urlsafe_base64 #=> "b4GOKm4pOYU_-BOXcrUGDg"
p SecureRandom.urlsafe_base64 #=> "UZLdOkzop70Ddx-IJR0ABg"

p SecureRandom.urlsafe_base64(nil, true) #=> "i0XQ-7gglIsHGV2_BNPrdQ=="
p SecureRandom.urlsafe_base64(nil, true) #=> "-M8rLhr7JEpJlqFGUMmOxg=="

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

See RFC 3548 for the definition of URL-safe base64.

# File lib/securerandom.rb, line 169
def urlsafe_base64(n=nil, padding=false)
  s = [random_bytes(n)].pack("m0")
  s.tr!("+/", "-_")
  s.delete!("=") unless padding
  s
end
uuid() Show source
# SecureRandom.random_number generates a random number.
#
# If a positive integer is given as _n_,
# +SecureRandom.random_number+ returns an integer, such that:
# +0 <= SecureRandom.random_number(n) < n+.
#
#   p SecureRandom.random_number(100) #=> 15
#   p SecureRandom.random_number(100) #=> 88
#
# If 0 is given or an argument is not given,
# +SecureRandom.random_number+ returns a float, such that:
# +0.0 <= SecureRandom.random_number() < 1.0+.
#
#   p SecureRandom.random_number #=> 0.596506046187744
#   p SecureRandom.random_number #=> 0.350621695741409
#
def random_number(n=0)
  if 0 < n
    if defined? OpenSSL::BN
      OpenSSL::BN.rand_range(n).to_i
    else
      hex = n.to_s(16)
      hex = '0' + hex if (hex.length & 1) == 1
      bin = [hex].pack("H*")
      mask = bin[0].ord
      mask |= mask >> 1
      mask |= mask >> 2
      mask |= mask >> 4
      begin
        rnd = random_bytes(bin.length)
        rnd[0] = (rnd[0].ord & mask).chr
      end until rnd < bin
      rnd.unpack("H*")[0].hex
    end
  else
    # assumption: Float::MANT_DIG <= 64
    if defined? OpenSSL::BN
      i64 = OpenSSL::BN.rand(64, -1).to_i
    else
      i64 = random_bytes(8).unpack("Q")[0]
    end
    Math.ldexp(i64 >> (64-Float::MANT_DIG), -Float::MANT_DIG)
  end
end

# SecureRandom.uuid generates a random v4 UUID (Universally Unique IDentifier). # # p SecureRandom.uuid #=> “2d931510-d99f-494a-8c67-87feb05e1594” # p SecureRandom.uuid #=> “bad85eb9-0713-4da7-8d36-07a8e4b00eab” # p SecureRandom.uuid #=> “62936e70-1815-439b-bf89-8492855a7e6b” # # The version 4 UUID is purely random (except the version). # It doesn't contain meaningful information such as MAC addresses, timestamps, etc. # # The result contains 122 random bits (15.25 random bytes). # # See RFC 4122 for details of UUID. #

# File lib/securerandom.rb, line 236
def uuid
  ary = random_bytes(16).unpack("NnnnnN")
  ary[2] = (ary[2] & 0x0fff) | 0x4000
  ary[3] = (ary[3] & 0x3fff) | 0x8000
  "%08x-%04x-%04x-%04x-%04x%08x" % ary
end

Private Instance Methods

gen_random(n) Show source
# File lib/securerandom.rb, line 244
def gen_random(n)
  self.bytes(n)
end

Ruby Core © 1993–2017 Yukihiro Matsumoto
Licensed under the Ruby License.
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Licensed under their own licenses.