Module | SecureRandom |
In: |
lib/compat/securerandom.rb
|
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.
# File lib/compat/securerandom.rb, line 145 145: def self.base64(n=nil) 146: [random_bytes(n)].pack("m*").delete("\n") 147: 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.
If secure random number generator is not available, NotImplementedError is raised.
# File lib/compat/securerandom.rb, line 131 131: def self.hex(n=nil) 132: random_bytes(n).unpack("H*")[0] 133: end
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.
# File lib/compat/securerandom.rb, line 52 52: def self.random_bytes(n=nil) 53: n ||= 16 54: 55: if defined? OpenSSL::Random 56: return OpenSSL::Random.random_bytes(n) 57: end 58: 59: if !defined?(@has_urandom) || @has_urandom 60: flags = File::RDONLY 61: flags |= File::NONBLOCK if defined? File::NONBLOCK 62: flags |= File::NOCTTY if defined? File::NOCTTY 63: flags |= File::NOFOLLOW if defined? File::NOFOLLOW 64: begin 65: File.open("/dev/urandom", flags) {|f| 66: unless f.stat.chardev? 67: raise Errno::ENOENT 68: end 69: @has_urandom = true 70: ret = f.readpartial(n) 71: if ret.length != n 72: raise NotImplementedError, 73: "Unexpected partial read from random device" 74: end 75: return ret 76: } 77: rescue Errno::ENOENT 78: @has_urandom = false 79: end 80: end 81: 82: if !defined?(@has_win32) 83: begin 84: require 'Win32API' 85: 86: crypt_acquire_context = Win32API.new( 87: "advapi32", "CryptAcquireContext", 'PPPII', 'L' 88: ) 89: @crypt_gen_random = Win32API.new( 90: "advapi32", "CryptGenRandom", 'LIP', 'L' 91: ) 92: 93: hProvStr = " " * 4 94: prov_rsa_full = 1 95: crypt_verifycontext = 0xF0000000 96: 97: if crypt_acquire_context.call( 98: hProvStr, nil, nil, prov_rsa_full, crypt_verifycontext) == 0 99: raise SystemCallError, 100: "CryptAcquireContext failed: #{lastWin32ErrorMessage}" 101: end 102: @hProv, = hProvStr.unpack('L') 103: 104: @has_win32 = true 105: rescue LoadError 106: @has_win32 = false 107: end 108: end 109: if @has_win32 110: bytes = " " * n 111: if @crypt_gen_random.call(@hProv, bytes.size, bytes) == 0 112: raise SystemCallError, 113: "CryptGenRandom failed: #{lastWin32ErrorMessage}" 114: end 115: return bytes 116: end 117: 118: raise NotImplementedError, "No random device" 119: end
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.
# File lib/compat/securerandom.rb, line 158 158: def self.random_number(n=0) 159: if 0 < n 160: hex = n.to_s(16) 161: hex = '0' + hex if (hex.length & 1) == 1 162: bin = [hex].pack("H*") 163: first = bin[0..0] 164: mask = first.respond_to?(:ord) ? first.ord : first.sum(8) 165: mask |= mask >> 1 166: mask |= mask >> 2 167: mask |= mask >> 4 168: begin 169: rnd = SecureRandom.random_bytes(bin.length) 170: first = rnd[0..0] 171: ordinal = first.respond_to?(:ord) ? first.ord : first.sum(8) 172: rnd[0..0] = (ordinal & mask).chr 173: end until rnd < bin 174: rnd.unpack("H*")[0].hex 175: else 176: # assumption: Float::MANT_DIG <= 64 177: i64 = SecureRandom.random_bytes(8).unpack("Q")[0] 178: Math.ldexp(i64 >> (64-Float::MANT_DIG), -Float::MANT_DIG) 179: end 180: end