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ASN.1/DER/BER PHP
2008-02-13 15:15:03 (ID: 74, Parent: 0, Type: post)

Je vous ai parlé dernièrement de ASN.1.  Voici un petit parseur de base en PHP

//Title: Simple PHP BER/DER/ASN.1 basic decoder
//Author: Jean-Luc Cyr
//Date: 2008-02-13
//Desc: Simple BER Printable string dumper
//	read BER data from a file

// Set input filename
$filename = 'o';
// Set max number of tag to parse (0 = no limit)
$limit = 0;

//Open data file
$f = fopen($filename,'rb');
//Set read tag number to 0
$c=0;
//While not end of file
while(!feof($f))
{
    //Read first block data type
    $type = ord(fread($f,1));
    if ($type==0)
      break;
    //Read first len block
    $len = ord(fread($f,1));
    if ($len==0)
      break;
    $le = 0;
    //If first bit of len is set (1)
    //we have a multiple bit len to read
    if (($len&128)==128)
    {
        echo "Big Len ".($len&127)." Bytes\r\n";
        for ($i = 0; $i < ($len&127); $i++)
          $le = $le * 256 + ord(fread($f,1));
        $len = $le;
    }
    //Findout data type (first 2 bits)
    $cl = ($type & (128+64) ) >> 6;
    switch($cl)
    {
     case 0:
        $cla = 'Universal';
        break;
     case 1:
        $cla = 'application';
        break;
     case 2:
        $cla = 'context-specific';
        break;
     case 3:
        $cla = 'private';
        break;
    }
    //Dump some info
    printf("[$cla] Type: %x (%d), len: %d\r\n",$type,$type,$len);
    //Read data chunk
    $data = fread($f,$len);
    //Display data chunk based on type
    switch($type)
    {
     case 2: // integer
        break;
     case 3: // bit string
        break;
     case 4: // octet string
        break;
     case 5: // null
        break;
     case 6: // object identifier
        break;
     case 16: // sequence and sequence of
        break;
     case 17: // set and set of
        break;
     case 19: //string
        printf("Data: $data\r\n");
        break;
     case 20: // t61string
        break;
     case 22: // ia5string
        break;
     case 23: // utctime
        break;
     default:
        #printf("Data: $data\r\n");
        break;
    }
    //increment count
    $c++;
    //check if we reach the number of tag specified
    if (($c>$limit)&&($limit>0)) break;
}

//close our input file
fclose($f);