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Cross Device Implementation

Methods to enable Criteo Cross Device

To provide the most flexibility possible to clients, Criteo offers two methods to handle the user’s email addresses, hashed or plain text.

Please use the setEmail event if you are passing the plain text email and the setHashedEmail event if you are passing the MD5 hashed email.

Before hashing or when passing plain text, all users’ email addresses need to be:

  • Trimmed (removing all spaces before and after the user's email address).
  • Converted to lowercase.
  • Encoded in UTF-8.

Cross Device parameters 

We recommend you send an email address that has already been hashed via a dedicated function (using an MD5 algorithm). Here is an example of the MD5 hashed email sent in the setHashedEmail event:

{ event: "setHashedEmail", email: "b58996c504c5638798eb6b511e6f49af" },

In the event that an unhashed email address is sent, Criteo will then encrypt the user's email address automatically before it is saved in our database. Here is an example of the plain-text email sent in the setEmail event:

{ event: "setEmail", email: "user@example.com" },

In the event that you are unable to pass either an unhashed or hashed email address, please simply pass us an empty string:

{ event: "setHashedEmail", email: "" },

Hashing functions

If you are hasing the user's email addresses before it is passed to Criteo, you can use one of the following functions to ensure proper encryption.

Hashing function using PHP

$source_address = "uSèr@example.Com ";
$processed_address = strtolower($source_address); //convert address to lower case
$processed_address = trim($processed_address); //trimming leading and trailing spaces
$processed_address = mb_convert_encoding($processed_address, "UTF-8", "ISO-8859-1"); //conversion from ISO-8859-1 to UTF-8 (replace "ISO-8859-1" with the source encoding of your string)
$processed_address = md5($processed_address); //hash address with MD5 algorithm
echo "Source e-mail: ".$source_address." | Hashed e-mail: ".$processed_address;

Hashing function using C#  

using System; 
 using System.Collections.Generic; using System.Linq;
 using System.Text;
 using System.Security.Cryptography;
 namespace Sample_EmailHashing_code
 {
     public class CriteoHashedEmailFormatter
     {
         private static MD5 _md5;
         private static MD5 Md5
         {
             get { return _md5 ?? (_md5 = MD5.Create()); }
         }
         private static string Md5Encode(string sourceString)
         {
             byte[] inputBytes = Encoding.UTF8.GetBytes(sourceString);
             byte[] hash = Md5.ComputeHash(inputBytes);
             var sb = new StringBuilder(32);
             foreach (byte b in hash)
                 sb.Append(b.ToString("x2"));
             return sb.ToString();
         }
         public static string HashEmail(string sourceEmail)
         {
             String processedEmail;
             processedEmail = sourceEmail.ToLowerInvariant(); //conversion to lower case
             processedEmail = processedEmail.Trim(); //trimming leading and trailing spaces
             //conversion to UTF-8 and hashing with MD5
             processedEmail = Md5Encode(processedEmail);
             return processedEmail;
         }
     }
     class SampleEmailHashing
     {
         static void Main(string[] args)
         {
             String sourceEmail = "   uSèr@example.Com   ";
             String processedEmail =
CriteoHashedEmailFormatter.HashEmail(sourceEmail);
             Console.WriteLine(processedEmail);
             Console.ReadKey();
         }
     }
 }

 

Hashing function using PHP

Click here to expand

 import java.io.*;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class SampleEmailHashing {
     public static void main(String[] args) {          
     String sourceEmail = new String(" uSèr@example.Com ");
        String processedEmail = FormatMail(sourceEmail);
        System.out.println(processedEmail);
     }
     //Method to format the source Email, converting to lower case and removing spaces     private static String FormatMail(String mail) {
         String newMail = new String(mail);
         // conversion to lower case characters
         newMail = newMail.toLowerCase();
         //remove empty spaces
         newMail = newMail.trim();
         newMail = md5Java(newMail);      
            
return newMail;
     }
     
//Method to encrypt email address using MD5
     public static String md5Java(String message) {         String digest = null;         try {
             //conversion to UTF-8 and hashing with MD5             MessageDigest md = MessageDigest.getInstance("MD5");
             byte[] hash = md.digest(message.getBytes("UTF-8"));
             StringBuilder sb = new StringBuilder(2 * hash.length);
             for (byte b : hash) {
                 sb.append(String.format("%02x", b & 0xff));
             }
             digest = sb.toString();
         } catch (UnsupportedEncodingException ex) {
             ex.printStackTrace();
         } catch (NoSuchAlgorithmException ex) {
             ex.printStackTrace();
         }         return digest;
     }
}

Hashing function using Perl  

#!/usr/bin/perl
use strict;
use warnings;
use Digest::MD5 qw(md5 md5_hex);
use Encode;
my $original_email  = qw/ uSèr@example.Com /;
my $processed_email = lc($original_email);
    $processed_email =~ s/^\s+//;
    $processed_email =~ s/\s+$//;
    $processed_email = encode_utf8($processed_email);
    $processed_email = md5_hex($processed_email);
print "Original email:\t$original_email\n";
print "Hashed email:\t$processed_email \n";

Hashing function using JavaScript

function utf8_encode(argString) {

  if (argString === null || typeof argString === 'undefined') {
    return '';
  }

  var string = (argString + ''); // .replace(/\r\n/g, "\n").replace(/\r/g, "\n");
  var utftext = '',
    start, end, stringl = 0;

  start = end = 0;
  stringl = string.length;
  for (var n = 0; n < stringl; n++) {
    var c1 = string.charCodeAt(n);
    var enc = null;

    if (c1 < 128) {
      end++;
    } else if (c1 > 127 && c1 < 2048) {
      enc = String.fromCharCode(
        (c1 >> 6) | 192, (c1 & 63) | 128
      );
    } else if ((c1 & 0xF800) != 0xD800) {
      enc = String.fromCharCode(
        (c1 >> 12) | 224, ((c1 >> 6) & 63) | 128, (c1 & 63) | 128
      );
    } else { // surrogate pairs
      if ((c1 & 0xFC00) != 0xD800) {
        throw new RangeError('Unmatched trail surrogate at ' + n);
      }
      var c2 = string.charCodeAt(++n);
      if ((c2 & 0xFC00) != 0xDC00) {
        throw new RangeError('Unmatched lead surrogate at ' + (n - 1));
      }
      c1 = ((c1 & 0x3FF) << 10) + (c2 & 0x3FF) + 0x10000;
      enc = String.fromCharCode(
        (c1 >> 18) | 240, ((c1 >> 12) & 63) | 128, ((c1 >> 6) & 63) | 128, (c1 & 63) | 128
      );
    }
    if (enc !== null) {
      if (end > start) {
        utftext += string.slice(start, end);
      }
      utftext += enc;
      start = end = n + 1;
    }
  }

  if (end > start) {
    utftext += string.slice(start, stringl);
  }

  return utftext;
}


function md5(str) {

  var str = str.toLowerCase();
  var xl;

  var rotateLeft = function(lValue, iShiftBits) {
    return (lValue << iShiftBits) | (lValue >>> (32 - iShiftBits));
  };

  var addUnsigned = function(lX, lY) {
    var lX4, lY4, lX8, lY8, lResult;
    lX8 = (lX & 0x80000000);
    lY8 = (lY & 0x80000000);
    lX4 = (lX & 0x40000000);
    lY4 = (lY & 0x40000000);
    lResult = (lX & 0x3FFFFFFF) + (lY & 0x3FFFFFFF);
    if (lX4 & lY4) {
      return (lResult ^ 0x80000000 ^ lX8 ^ lY8);
    }
    if (lX4 | lY4) {
      if (lResult & 0x40000000) {
        return (lResult ^ 0xC0000000 ^ lX8 ^ lY8);
      } else {
        return (lResult ^ 0x40000000 ^ lX8 ^ lY8);
      }
    } else {
      return (lResult ^ lX8 ^ lY8);
    }
  };

  var _F = function(x, y, z) {
    return (x & y) | ((~x) & z);
  };
  var _G = function(x, y, z) {
    return (x & z) | (y & (~z));
  };
  var _H = function(x, y, z) {
    return (x ^ y ^ z);
  };
  var _I = function(x, y, z) {
    return (y ^ (x | (~z)));
  };

  var _FF = function(a, b, c, d, x, s, ac) {
    a = addUnsigned(a, addUnsigned(addUnsigned(_F(b, c, d), x), ac));
    return addUnsigned(rotateLeft(a, s), b);
  };

  var _GG = function(a, b, c, d, x, s, ac) {
    a = addUnsigned(a, addUnsigned(addUnsigned(_G(b, c, d), x), ac));
    return addUnsigned(rotateLeft(a, s), b);
  };

  var _HH = function(a, b, c, d, x, s, ac) {
    a = addUnsigned(a, addUnsigned(addUnsigned(_H(b, c, d), x), ac));
    return addUnsigned(rotateLeft(a, s), b);
  };

  var _II = function(a, b, c, d, x, s, ac) {
    a = addUnsigned(a, addUnsigned(addUnsigned(_I(b, c, d), x), ac));
    return addUnsigned(rotateLeft(a, s), b);
  };

  var convertToWordArray = function(str) {
    var lWordCount;
    var lMessageLength = str.length;
    var lNumberOfWords_temp1 = lMessageLength + 8;
    var lNumberOfWords_temp2 = (lNumberOfWords_temp1 - (lNumberOfWords_temp1 % 64)) / 64;
    var lNumberOfWords = (lNumberOfWords_temp2 + 1) * 16;
    var lWordArray = new Array(lNumberOfWords - 1);
    var lBytePosition = 0;
    var lByteCount = 0;
    while (lByteCount < lMessageLength) {
      lWordCount = (lByteCount - (lByteCount % 4)) / 4;
      lBytePosition = (lByteCount % 4) * 8;
      lWordArray[lWordCount] = (lWordArray[lWordCount] | (str.charCodeAt(lByteCount) << lBytePosition));
      lByteCount++;
    }
    lWordCount = (lByteCount - (lByteCount % 4)) / 4;
    lBytePosition = (lByteCount % 4) * 8;
    lWordArray[lWordCount] = lWordArray[lWordCount] | (0x80 << lBytePosition);
    lWordArray[lNumberOfWords - 2] = lMessageLength << 3;
    lWordArray[lNumberOfWords - 1] = lMessageLength >>> 29;
    return lWordArray;
  };

  var wordToHex = function(lValue) {
    var wordToHexValue = '',
      wordToHexValue_temp = '',
      lByte, lCount;
    for (lCount = 0; lCount <= 3; lCount++) {
      lByte = (lValue >>> (lCount * 8)) & 255;
      wordToHexValue_temp = '0' + lByte.toString(16);
      wordToHexValue = wordToHexValue + wordToHexValue_temp.substr(wordToHexValue_temp.length - 2, 2);
    }
    return wordToHexValue;
  };

  var x = [],
    k, AA, BB, CC, DD, a, b, c, d, S11 = 7,
    S12 = 12,
    S13 = 17,
    S14 = 22,
    S21 = 5,
    S22 = 9,
    S23 = 14,
    S24 = 20,
    S31 = 4,
    S32 = 11,
    S33 = 16,
    S34 = 23,
    S41 = 6,
    S42 = 10,
    S43 = 15,
    S44 = 21;

  str = utf8_encode(str);
  x = convertToWordArray(str);
  a = 0x67452301;
  b = 0xEFCDAB89;
  c = 0x98BADCFE;
  d = 0x10325476;

  xl = x.length;
  for (k = 0; k < xl; k += 16) {
    AA = a;
    BB = b;
    CC = c;
    DD = d;
    a = _FF(a, b, c, d, x[k + 0], S11, 0xD76AA478);
    d = _FF(d, a, b, c, x[k + 1], S12, 0xE8C7B756);
    c = _FF(c, d, a, b, x[k + 2], S13, 0x242070DB);
    b = _FF(b, c, d, a, x[k + 3], S14, 0xC1BDCEEE);
    a = _FF(a, b, c, d, x[k + 4], S11, 0xF57C0FAF);
    d = _FF(d, a, b, c, x[k + 5], S12, 0x4787C62A);
    c = _FF(c, d, a, b, x[k + 6], S13, 0xA8304613);
    b = _FF(b, c, d, a, x[k + 7], S14, 0xFD469501);
    a = _FF(a, b, c, d, x[k + 8], S11, 0x698098D8);
    d = _FF(d, a, b, c, x[k + 9], S12, 0x8B44F7AF);
    c = _FF(c, d, a, b, x[k + 10], S13, 0xFFFF5BB1);
    b = _FF(b, c, d, a, x[k + 11], S14, 0x895CD7BE);
    a = _FF(a, b, c, d, x[k + 12], S11, 0x6B901122);
    d = _FF(d, a, b, c, x[k + 13], S12, 0xFD987193);
    c = _FF(c, d, a, b, x[k + 14], S13, 0xA679438E);
    b = _FF(b, c, d, a, x[k + 15], S14, 0x49B40821);
    a = _GG(a, b, c, d, x[k + 1], S21, 0xF61E2562);
    d = _GG(d, a, b, c, x[k + 6], S22, 0xC040B340);
    c = _GG(c, d, a, b, x[k + 11], S23, 0x265E5A51);
    b = _GG(b, c, d, a, x[k + 0], S24, 0xE9B6C7AA);
    a = _GG(a, b, c, d, x[k + 5], S21, 0xD62F105D);
    d = _GG(d, a, b, c, x[k + 10], S22, 0x2441453);
    c = _GG(c, d, a, b, x[k + 15], S23, 0xD8A1E681);
    b = _GG(b, c, d, a, x[k + 4], S24, 0xE7D3FBC8);
    a = _GG(a, b, c, d, x[k + 9], S21, 0x21E1CDE6);
    d = _GG(d, a, b, c, x[k + 14], S22, 0xC33707D6);
    c = _GG(c, d, a, b, x[k + 3], S23, 0xF4D50D87);
    b = _GG(b, c, d, a, x[k + 8], S24, 0x455A14ED);
    a = _GG(a, b, c, d, x[k + 13], S21, 0xA9E3E905);
    d = _GG(d, a, b, c, x[k + 2], S22, 0xFCEFA3F8);
    c = _GG(c, d, a, b, x[k + 7], S23, 0x676F02D9);
    b = _GG(b, c, d, a, x[k + 12], S24, 0x8D2A4C8A);
    a = _HH(a, b, c, d, x[k + 5], S31, 0xFFFA3942);
    d = _HH(d, a, b, c, x[k + 8], S32, 0x8771F681);
    c = _HH(c, d, a, b, x[k + 11], S33, 0x6D9D6122);
    b = _HH(b, c, d, a, x[k + 14], S34, 0xFDE5380C);
    a = _HH(a, b, c, d, x[k + 1], S31, 0xA4BEEA44);
    d = _HH(d, a, b, c, x[k + 4], S32, 0x4BDECFA9);
    c = _HH(c, d, a, b, x[k + 7], S33, 0xF6BB4B60);
    b = _HH(b, c, d, a, x[k + 10], S34, 0xBEBFBC70);
    a = _HH(a, b, c, d, x[k + 13], S31, 0x289B7EC6);
    d = _HH(d, a, b, c, x[k + 0], S32, 0xEAA127FA);
    c = _HH(c, d, a, b, x[k + 3], S33, 0xD4EF3085);
    b = _HH(b, c, d, a, x[k + 6], S34, 0x4881D05);
    a = _HH(a, b, c, d, x[k + 9], S31, 0xD9D4D039);
    d = _HH(d, a, b, c, x[k + 12], S32, 0xE6DB99E5);
    c = _HH(c, d, a, b, x[k + 15], S33, 0x1FA27CF8);
    b = _HH(b, c, d, a, x[k + 2], S34, 0xC4AC5665);
    a = _II(a, b, c, d, x[k + 0], S41, 0xF4292244);
    d = _II(d, a, b, c, x[k + 7], S42, 0x432AFF97);
    c = _II(c, d, a, b, x[k + 14], S43, 0xAB9423A7);
    b = _II(b, c, d, a, x[k + 5], S44, 0xFC93A039);
    a = _II(a, b, c, d, x[k + 12], S41, 0x655B59C3);
    d = _II(d, a, b, c, x[k + 3], S42, 0x8F0CCC92);
    c = _II(c, d, a, b, x[k + 10], S43, 0xFFEFF47D);
    b = _II(b, c, d, a, x[k + 1], S44, 0x85845DD1);
    a = _II(a, b, c, d, x[k + 8], S41, 0x6FA87E4F);
    d = _II(d, a, b, c, x[k + 15], S42, 0xFE2CE6E0);
    c = _II(c, d, a, b, x[k + 6], S43, 0xA3014314);
    b = _II(b, c, d, a, x[k + 13], S44, 0x4E0811A1);
    a = _II(a, b, c, d, x[k + 4], S41, 0xF7537E82);
    d = _II(d, a, b, c, x[k + 11], S42, 0xBD3AF235);
    c = _II(c, d, a, b, x[k + 2], S43, 0x2AD7D2BB);
    b = _II(b, c, d, a, x[k + 9], S44, 0xEB86D391);
    a = addUnsigned(a, AA);
    b = addUnsigned(b, BB);
    c = addUnsigned(c, CC);
    d = addUnsigned(d, DD);
  }

  var temp = wordToHex(a) + wordToHex(b) + wordToHex(c) + wordToHex(d);

  return temp.toLowerCase();
}
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