# = 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 # # == 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" # ... begin require 'openssl' rescue LoadError end module SecureRandom # 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. # # 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 secure random number generator is not available, # NotImplementedError is raised. def self.random_bytes(n=nil) n = n ? n.to_int : 16 if defined? OpenSSL::Random @pid = 0 if !defined?(@pid) pid = $$ if @pid != pid now = Time.now ary = [now.to_i, now.nsec, @pid, pid] OpenSSL::Random.seed(ary.to_s) @pid = pid end return OpenSSL::Random.random_bytes(n) end if !defined?(@has_urandom) || @has_urandom flags = File::RDONLY flags |= File::NONBLOCK if defined? File::NONBLOCK flags |= File::NOCTTY if defined? File::NOCTTY begin File.open("/dev/urandom", flags) {|f| unless f.stat.chardev? raise Errno::ENOENT end @has_urandom = true ret = f.read(n) if ret.length != n raise NotImplementedError, "Unexpected partial read from random device: only #{ret.length} for #{n} bytes" end return ret } rescue Errno::ENOENT @has_urandom = false end end if !defined?(@has_win32) begin require 'Win32API' crypt_acquire_context = Win32API.new("advapi32", "CryptAcquireContext", 'PPPII', 'L') @crypt_gen_random = Win32API.new("advapi32", "CryptGenRandom", 'VIP', 'L') hProvStr = " " * DL::SIZEOF_VOIDP prov_rsa_full = 1 crypt_verifycontext = 0xF0000000 if crypt_acquire_context.call(hProvStr, nil, nil, prov_rsa_full, crypt_verifycontext) == 0 raise SystemCallError, "CryptAcquireContext failed: #{lastWin32ErrorMessage}" end type = DL::SIZEOF_VOIDP == DL::SIZEOF_LONG_LONG ? 'q' : 'l' @hProv, = hProvStr.unpack(type) @has_win32 = true rescue LoadError @has_win32 = false end end if @has_win32 bytes = " ".force_encoding("ASCII-8BIT") * n if @crypt_gen_random.call(@hProv, bytes.size, bytes) == 0 raise SystemCallError, "CryptGenRandom failed: #{lastWin32ErrorMessage}" end return bytes end raise NotImplementedError, "No random device" end # 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. # # The result may contain 0-9 and a-f. # # p SecureRandom.hex #=> "eb693ec8252cd630102fd0d0fb7c3485" # p SecureRandom.hex #=> "91dc3bfb4de5b11d029d376634589b61" # # If secure random number generator is not available, # NotImplementedError is raised. def self.hex(n=nil) random_bytes(n).unpack("H*")[0] end # 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. # # The result may contain A-Z, a-z, 0-9, "+", "/" and "=". # # p SecureRandom.base64 #=> "/2BuBuLf3+WfSKyQbRcc/A==" # p SecureRandom.base64 #=> "6BbW0pxO0YENxn38HMUbcQ==" # # If secure random number generator is not available, # NotImplementedError is raised. # # See RFC 3548 for the definition of base64. def self.base64(n=nil) [random_bytes(n)].pack("m*").delete("\n") end # SecureRandom.urlsafe_base64 generates a random URL-safe 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. # # 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 secure random number generator is not available, # NotImplementedError is raised. # # See RFC 3548 for the definition of URL-safe base64. def self.urlsafe_base64(n=nil, padding=false) s = [random_bytes(n)].pack("m*") s.delete!("\n") s.tr!("+/", "-_") s.delete!("=") if !padding s end # SecureRandom.random_number generates a random number. # # If a positive integer is given as _n_, # SecureRandom.random_number returns an integer: # 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: # 0.0 <= SecureRandom.random_number() < 1.0. # # p SecureRandom.random_number #=> 0.596506046187744 # p SecureRandom.random_number #=> 0.350621695741409 # def self.random_number(n=0) if 0 < n 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 = SecureRandom.random_bytes(bin.length) rnd[0] = (rnd[0].ord & mask).chr end until rnd < bin rnd.unpack("H*")[0].hex else # assumption: Float::MANT_DIG <= 64 i64 = SecureRandom.random_bytes(8).unpack("Q")[0] Math.ldexp(i64 >> (64-Float::MANT_DIG), -Float::MANT_DIG) end end # SecureRandom.uuid generates a v4 random 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 address, time, etc. # # See RFC 4122 for details of UUID. # def self.uuid ary = self.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 # Following code is based on David Garamond's GUID library for Ruby. def self.lastWin32ErrorMessage # :nodoc: get_last_error = Win32API.new("kernel32", "GetLastError", '', 'L') format_message = Win32API.new("kernel32", "FormatMessageA", 'LPLLPLPPPPPPPP', 'L') format_message_ignore_inserts = 0x00000200 format_message_from_system = 0x00001000 code = get_last_error.call msg = "\0" * 1024 len = format_message.call(format_message_ignore_inserts + format_message_from_system, 0, code, 0, msg, 1024, nil, nil, nil, nil, nil, nil, nil, nil) msg[0, len].force_encoding("filesystem").tr("\r", '').chomp end end

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