File modules/security/Base2n.class.php
Last commit: Wed Dec 6 23:53:14 2017 +0100 Jan Dankert Eigener Namespace für Security-Klassen.
1 <?php 2 namespace security; 3 /** 4 * Binary-to-text PHP Utilities 5 * 6 * @package binary-to-text-php 7 * @link https://github.com/ademarre/binary-to-text-php 8 * @author Andre DeMarre 9 * @copyright 2009-2013 Andre DeMarre 10 * @license http://opensource.org/licenses/MIT MIT 11 */ 12 13 /** 14 * Class for binary-to-text encoding with a base of 2^n 15 * 16 * The Base2n class is for binary-to-text conversion. It employs a 17 * generalization of the algorithms used by many encoding schemes that 18 * use a fixed number of bits to encode each character. In other words, 19 * the base is a power of 2. 20 * 21 * Earlier versions of this class were named 22 * FixedBitNotation and FixedBitEncoding. 23 * 24 * @package binary-to-text-php 25 */ 26 class Base2n 27 { 28 protected $_chars; 29 protected $_bitsPerCharacter; 30 protected $_radix; 31 protected $_rightPadFinalBits; 32 protected $_padFinalGroup; 33 protected $_padCharacter; 34 protected $_caseSensitive; 35 protected $_charmap; 36 37 /** 38 * Constructor 39 * 40 * @param integer $bitsPerCharacter Bits to use for each encoded character 41 * @param string $chars Base character alphabet 42 * @param boolean $caseSensitive To decode in a case-sensitive manner 43 * @param boolean $rightPadFinalBits How to encode last character 44 * @param boolean $padFinalGroup Add padding to end of encoded output 45 * @param string $padCharacter Character to use for padding 46 * 47 * @throws InvalidArgumentException for incompatible parameters 48 */ 49 public function __construct( 50 $bitsPerCharacter, 51 $chars = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-_', 52 $caseSensitive = TRUE, $rightPadFinalBits = FALSE, 53 $padFinalGroup = FALSE, $padCharacter = '=') 54 { 55 // Ensure validity of $chars 56 if (!is_string($chars) || ($charLength = strlen($chars)) < 2) { 57 throw new InvalidArgumentException('$chars must be a string of at least two characters'); 58 } 59 60 // Ensure validity of $padCharacter 61 if ($padFinalGroup) { 62 if (!is_string($padCharacter) || !isset($padCharacter[0])) { 63 throw new InvalidArgumentException('$padCharacter must be a string of one character'); 64 } 65 66 if ($caseSensitive) { 67 $padCharFound = strpos($chars, $padCharacter[0]); 68 } else { 69 $padCharFound = stripos($chars, $padCharacter[0]); 70 } 71 72 if ($padCharFound !== FALSE) { 73 throw new InvalidArgumentException('$padCharacter can not be a member of $chars'); 74 } 75 } 76 77 // Ensure validity of $bitsPerCharacter 78 if (!is_int($bitsPerCharacter)) { 79 throw new InvalidArgumentException('$bitsPerCharacter must be an integer'); 80 } 81 82 if ($bitsPerCharacter < 1) { 83 // $bitsPerCharacter must be at least 1 84 throw new InvalidArgumentException('$bitsPerCharacter can not be less than 1'); 85 86 } elseif ($charLength < 1 << $bitsPerCharacter) { 87 // Character length of $chars is too small for $bitsPerCharacter 88 // Find greatest acceptable value of $bitsPerCharacter 89 $bitsPerCharacter = 1; 90 $radix = 2; 91 92 while ($charLength >= ($radix <<= 1) && $bitsPerCharacter < 8) { 93 $bitsPerCharacter++; 94 } 95 96 $radix >>= 1; 97 throw new InvalidArgumentException( 98 '$bitsPerCharacter can not be more than ' . $bitsPerCharacter 99 . ' given $chars length of ' . $charLength 100 . ' (max radix ' . $radix . ')'); 101 102 } elseif ($bitsPerCharacter > 8) { 103 // $bitsPerCharacter must not be greater than 8 104 throw new InvalidArgumentException('$bitsPerCharacter can not be greater than 8'); 105 106 } else { 107 $radix = 1 << $bitsPerCharacter; 108 } 109 110 $this->_chars = $chars; 111 $this->_bitsPerCharacter = $bitsPerCharacter; 112 $this->_radix = $radix; 113 $this->_rightPadFinalBits = $rightPadFinalBits; 114 $this->_padFinalGroup = $padFinalGroup; 115 $this->_padCharacter = $padCharacter[0]; 116 $this->_caseSensitive = $caseSensitive; 117 } 118 119 /** 120 * Encode a string 121 * 122 * @param string $rawString Binary data to encode 123 * @return string 124 */ 125 public function encode($rawString) 126 { 127 // Unpack string into an array of bytes 128 $bytes = unpack('C*', $rawString); 129 $byteCount = count($bytes); 130 131 $encodedString = ''; 132 $byte = array_shift($bytes); 133 $bitsRead = 0; 134 $oldBits = 0; 135 136 $chars = $this->_chars; 137 $bitsPerCharacter = $this->_bitsPerCharacter; 138 $rightPadFinalBits = $this->_rightPadFinalBits; 139 $padFinalGroup = $this->_padFinalGroup; 140 $padCharacter = $this->_padCharacter; 141 142 $charsPerByte = 8 / $bitsPerCharacter; 143 $encodedLength = $byteCount * $charsPerByte; 144 145 // Generate encoded output; each loop produces one encoded character 146 for ($c = 0; $c < $encodedLength; $c++) { 147 148 // Get the bits needed for this encoded character 149 if ($bitsRead + $bitsPerCharacter > 8) { 150 // Not enough bits remain in this byte for the current character 151 // Save the remaining bits before getting the next byte 152 $oldBitCount = 8 - $bitsRead; 153 $oldBits = $byte ^ ($byte >> $oldBitCount << $oldBitCount); 154 $newBitCount = $bitsPerCharacter - $oldBitCount; 155 156 if (!$bytes) { 157 // Last bits; match final character and exit loop 158 if ($rightPadFinalBits) $oldBits <<= $newBitCount; 159 $encodedString .= $chars[$oldBits]; 160 161 if ($padFinalGroup) { 162 // Array of the lowest common multiples of $bitsPerCharacter and 8, divided by 8 163 $lcmMap = array(1 => 1, 2 => 1, 3 => 3, 4 => 1, 5 => 5, 6 => 3, 7 => 7, 8 => 1); 164 $bytesPerGroup = $lcmMap[$bitsPerCharacter]; 165 $pads = $bytesPerGroup * $charsPerByte - ceil((strlen($rawString) % $bytesPerGroup) * $charsPerByte); 166 $encodedString .= str_repeat($padCharacter, $pads); 167 } 168 169 break; 170 } 171 172 // Get next byte 173 $byte = array_shift($bytes); 174 $bitsRead = 0; 175 176 } else { 177 $oldBitCount = 0; 178 $newBitCount = $bitsPerCharacter; 179 } 180 181 // Read only the needed bits from this byte 182 $bits = $byte >> 8 - ($bitsRead + ($newBitCount)); 183 $bits ^= $bits >> $newBitCount << $newBitCount; 184 $bitsRead += $newBitCount; 185 186 if ($oldBitCount) { 187 // Bits come from seperate bytes, add $oldBits to $bits 188 $bits = ($oldBits << $newBitCount) | $bits; 189 } 190 191 $encodedString .= $chars[$bits]; 192 } 193 194 return $encodedString; 195 } 196 197 /** 198 * Decode a string 199 * 200 * @param string $encodedString Data to decode 201 * @param boolean $strict Returns NULL if $encodedString contains an undecodable character 202 * @return string 203 */ 204 public function decode($encodedString, $strict = FALSE) 205 { 206 if (!$encodedString || !is_string($encodedString)) { 207 // Empty string, nothing to decode 208 return ''; 209 } 210 211 $chars = $this->_chars; 212 $bitsPerCharacter = $this->_bitsPerCharacter; 213 $radix = $this->_radix; 214 $rightPadFinalBits = $this->_rightPadFinalBits; 215 $padFinalGroup = $this->_padFinalGroup; 216 $padCharacter = $this->_padCharacter; 217 $caseSensitive = $this->_caseSensitive; 218 219 // Get index of encoded characters 220 if ($this->_charmap) { 221 $charmap = $this->_charmap; 222 223 } else { 224 $charmap = array(); 225 226 for ($i = 0; $i < $radix; $i++) { 227 $charmap[$chars[$i]] = $i; 228 } 229 230 $this->_charmap = $charmap; 231 } 232 233 // The last encoded character is $encodedString[$lastNotatedIndex] 234 $lastNotatedIndex = strlen($encodedString) - 1; 235 236 // Remove trailing padding characters 237 if ($padFinalGroup) { 238 while ($encodedString[$lastNotatedIndex] === $padCharacter) { 239 $encodedString = substr($encodedString, 0, $lastNotatedIndex); 240 $lastNotatedIndex--; 241 } 242 } 243 244 $rawString = ''; 245 $byte = 0; 246 $bitsWritten = 0; 247 248 // Convert each encoded character to a series of unencoded bits 249 for ($c = 0; $c <= $lastNotatedIndex; $c++) { 250 251 if (!$caseSensitive && !isset($charmap[$encodedString[$c]])) { 252 // Encoded character was not found; try other case 253 if (isset($charmap[$cUpper = strtoupper($encodedString[$c])])) { 254 $charmap[$encodedString[$c]] = $charmap[$cUpper]; 255 256 } elseif (isset($charmap[$cLower = strtolower($encodedString[$c])])) { 257 $charmap[$encodedString[$c]] = $charmap[$cLower]; 258 } 259 } 260 261 if (isset($charmap[$encodedString[$c]])) { 262 $bitsNeeded = 8 - $bitsWritten; 263 $unusedBitCount = $bitsPerCharacter - $bitsNeeded; 264 265 // Get the new bits ready 266 if ($bitsNeeded > $bitsPerCharacter) { 267 // New bits aren't enough to complete a byte; shift them left into position 268 $newBits = $charmap[$encodedString[$c]] << $bitsNeeded - $bitsPerCharacter; 269 $bitsWritten += $bitsPerCharacter; 270 271 } elseif ($c !== $lastNotatedIndex || $rightPadFinalBits) { 272 // Zero or more too many bits to complete a byte; shift right 273 $newBits = $charmap[$encodedString[$c]] >> $unusedBitCount; 274 $bitsWritten = 8; //$bitsWritten += $bitsNeeded; 275 276 } else { 277 // Final bits don't need to be shifted 278 $newBits = $charmap[$encodedString[$c]]; 279 $bitsWritten = 8; 280 } 281 282 $byte |= $newBits; 283 284 if ($bitsWritten === 8 || $c === $lastNotatedIndex) { 285 // Byte is ready to be written 286 $rawString .= pack('C', $byte); 287 288 if ($c !== $lastNotatedIndex) { 289 // Start the next byte 290 $bitsWritten = $unusedBitCount; 291 $byte = ($charmap[$encodedString[$c]] ^ ($newBits << $unusedBitCount)) << 8 - $bitsWritten; 292 } 293 } 294 295 } elseif ($strict) { 296 // Unable to decode character; abort 297 return NULL; 298 } 299 } 300 301 return $rawString; 302 } 303 } 304 ?>
Downloadmodules/security/Base2n.class.php
History Wed, 6 Dec 2017 23:53:14 +0100 Jan Dankert Eigener Namespace für Security-Klassen. Sun, 3 Dec 2017 03:33:57 +0100 Jan Dankert Refactoring: Security-Funktionen in ein eigenes "Modul" ausgelagert.