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  • mcrypt_generic_init()

    (PHP 4 >= 4.0.2, PHP 5, PHP 7 < 7.2.0, PECL mcrypt >= 1.0.0)

    初始化加密所需的缓冲区

    Warning

    This function has beenDEPRECATEDas of PHP 7.1.0. Relying on this functionis highly discouraged.

    说明

    mcrypt_generic_init(resource $td,string $key,string $iv): int

    在每次调用mcrypt_generic()或mdecrypt_generic()函数之前必须调用本函数。

    参数

    $td

    加密描述符。

    $key

    调用mcrypt_enc_get_key_size()函数获得的密钥最大长度。小于最大长度的数值都被视为非法参数。

    $iv

    通常情况下,向量大小等于算法的分组大小,但是你应该通过mcrypt_enc_get_iv_size()函数来获得这个值。在 ECB 模式下,初始向量会被忽略,在 CFB,CBC,STREAM,nOFB 和 OFB 模式下,必须提供初始向量。初始向量要求是随机的,并且是唯一的(不需要是安全的)。加密和解密必须使用相同的初始向量。如果你不想使用初始向量,请将其设置为全 0 值,但是不建议你这么做。

    返回值

    如果发生错误,将会返回负数:-3 表示密钥长度有误,-4 表示内存分配失败,其他值表示未知错误,同时会显示对应的警告信息。如果传入参数不正确,返回FALSE

    参见

    The mcrypt implementation of RC2 algorithm supports an effective key length of 1024 bits only.
    It is however possible to use an effective key length in 1..1024 bits, by transforming the key before use as follows:
    <?php
    function transformKey($key, $effKeyLen)
    {
      $pitable = array(
        0xD9, 0x78, 0xF9, 0xC4, 0x19, 0xDD, 0xB5, 0xED, 0x28, 0xE9, 0xFD, 0x79, 0x4A, 0xA0, 0xD8, 0x9D,
        0xC6, 0x7E, 0x37, 0x83, 0x2B, 0x76, 0x53, 0x8E, 0x62, 0x4C, 0x64, 0x88, 0x44, 0x8B, 0xFB, 0xA2,
        0x17, 0x9A, 0x59, 0xF5, 0x87, 0xB3, 0x4F, 0x13, 0x61, 0x45, 0x6D, 0x8D, 0x09, 0x81, 0x7D, 0x32,
        0xBD, 0x8F, 0x40, 0xEB, 0x86, 0xB7, 0x7B, 0x0B, 0xF0, 0x95, 0x21, 0x22, 0x5C, 0x6B, 0x4E, 0x82,
        0x54, 0xD6, 0x65, 0x93, 0xCE, 0x60, 0xB2, 0x1C, 0x73, 0x56, 0xC0, 0x14, 0xA7, 0x8C, 0xF1, 0xDC,
        0x12, 0x75, 0xCA, 0x1F, 0x3B, 0xBE, 0xE4, 0xD1, 0x42, 0x3D, 0xD4, 0x30, 0xA3, 0x3C, 0xB6, 0x26,
        0x6F, 0xBF, 0x0E, 0xDA, 0x46, 0x69, 0x07, 0x57, 0x27, 0xF2, 0x1D, 0x9B, 0xBC, 0x94, 0x43, 0x03,
        0xF8, 0x11, 0xC7, 0xF6, 0x90, 0xEF, 0x3E, 0xE7, 0x06, 0xC3, 0xD5, 0x2F, 0xC8, 0x66, 0x1E, 0xD7,
        0x08, 0xE8, 0xEA, 0xDE, 0x80, 0x52, 0xEE, 0xF7, 0x84, 0xAA, 0x72, 0xAC, 0x35, 0x4D, 0x6A, 0x2A,
        0x96, 0x1A, 0xD2, 0x71, 0x5A, 0x15, 0x49, 0x74, 0x4B, 0x9F, 0xD0, 0x5E, 0x04, 0x18, 0xA4, 0xEC,
        0xC2, 0xE0, 0x41, 0x6E, 0x0F, 0x51, 0xCB, 0xCC, 0x24, 0x91, 0xAF, 0x50, 0xA1, 0xF4, 0x70, 0x39,
        0x99, 0x7C, 0x3A, 0x85, 0x23, 0xB8, 0xB4, 0x7A, 0xFC, 0x02, 0x36, 0x5B, 0x25, 0x55, 0x97, 0x31,
        0x2D, 0x5D, 0xFA, 0x98, 0xE3, 0x8A, 0x92, 0xAE, 0x05, 0xDF, 0x29, 0x10, 0x67, 0x6C, 0xBA, 0xC9,
        0xD3, 0x00, 0xE6, 0xCF, 0xE1, 0x9E, 0xA8, 0x2C, 0x63, 0x16, 0x01, 0x3F, 0x58, 0xE2, 0x89, 0xA9,
        0x0D, 0x38, 0x34, 0x1B, 0xAB, 0x33, 0xFF, 0xB0, 0xBB, 0x48, 0x0C, 0x5F, 0xB9, 0xB1, 0xCD, 0x2E,
        0xC5, 0xF3, 0xDB, 0x47, 0xE5, 0xA5, 0x9C, 0x77, 0x0A, 0xA6, 0x20, 0x68, 0xFE, 0x7F, 0xC1, 0xAD);
      $invpitable = array_flip($pitable);
      //  Apply the regular RC2 key expansion algorithm.
      $t = strlen($key);
      $key = array_values(unpack('C*C', $key));
      for ($i = $t; $i < 128; $i++)
        $key[$i] = $pitable[($key[$i - 1] + $key[$i - $t]) & 0xFF];
      $t8 = ($effKeyLen + 7) >> 3;
      $tm = 0xFF >> (8 * $t8 - $effKeyLen);
      $i = 128 - $t8;
      $key[$i] = $pitable[$key[$i] & $tm];
      while ($i--)
        $key[$i] = $pitable[$key[$i + 1] ^ $key[$i + $t8]];
      //  Map the first byte: this operation will be undone by
      //    mcrypt internals.
      $key[0] = $invpitable[$key[0]];
      //  Return the transformed key as a string.
      array_unshift($key, 'C*');
      return call_user_func_array('pack', $key);
    }
    //  Usage example
    $r = mcrypt_module_open(MCRYPT_RC2, $algoDir, $mode, $modeDir);
    mcrypt_generic_init($r, transformKey($originalKey, $effectiveKeyLength), $iv);
    ?>