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DUKPT Explained with examples – Cryptography & Payments

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It&#8217;ll then increment the value of its KSN and discard the future key it used.</li> <li>At this point you&#8217;ll probably have an encrypted track along with the KSN the swiper used to encrypt it.</li> <li>It&#8217;s your responsibility to determine what BDK was used to initialize this device, and from there you&#8217;ll use the BDK and KSN to rederive the IPEK, which is used to rederive the Session Key, which is finally used to decrypt the message.</li> </ol> <p>There&#8217;s a lot of technical information to be said about key management, but this isn&#8217;t the place for that. In some cases your provider/manufacturer (e.g. MagTek) will supply you with swipers that need to be initialized with an IPEK, and your supplier will usually have a manual that walks you through that process. If you&#8217;re doing encryption/decryption through a third party who also supplies swipers, they may have already loaded the devices with that information; what&#8217;s more is they may not even given you the BDK that belongs to your device in order to reduce the risk of security threats.</p> <hr /> <p><strong>Note:</strong> Key management is beyond the scope of this explanation. Whatever you do with your keys, just make sure it&#8217;s secure.</p> <hr /> <p>One methodology I&#8217;ve seen that&#8217;ll allow you to associate a particular KSN to a BDK is to take the current KSN you&#8217;ve been given, mask it to retrieve the Initial Key Serial Number (IKSN), and look up the BDK in a table that maps IKSNs to BDKs:</p> <p>Example:</p> <pre><code>ksn = FFFF9876543210E00008 iksn = ksn &amp; FFFFFFFFFFFFFFE00000 // FFFF9876543210E00000 </code></pre> <p>You&#8217;d then have a table that looks like:</p> <table> <thead> <tr> <th align="center">IKSN</th> <th align="center">BDK</th> </tr> </thead> <tbody> <tr> <td align="center">0xFFFF9876543210E00000</td> <td align="center">0123456789ABCDEFFEDCBA9876543210</td> </tr> <tr> <td align="center">&#8230;</td> <td align="center">&#8230;</td> </tr> </tbody> </table> <p>From which you could easily grab the BDK <code>0123456789ABCDEFFEDCBA9876543210</code>.</p> <h2><a id="user-content-algorithm" class="anchor" href="#algorithm"></a>Algorithm</h2> <hr /> <p><strong>Note:</strong> Assume that all numeric values are hexadecimal numbers, or the representation of a sequence of bytes as a hexadecimal number.</p> <hr /> <p>The following are the BDK, KSN, and encrypted track message (cryptogram) we&#8217;ve been given:</p> <pre><code>bdk = 0123456789ABCDEFFEDCBA9876543210 ksn = FFFF9876543210E00008 cryptogram = C25C1D1197D31CAA87285D59A892047426D9182EC11353C051ADD6D0F072A6CB3436560B3071FC1FD11D9F7E74886742D9BEE0CFD1EA1064C213BB55278B2F12 </code></pre> <p>Here&#8217;s an example of the unencrypted track 1 data (cryptogram above), and below that is its value in hex; this is what we&#8217;ll get after successfully decrypting the cryptogram:</p> <pre><code>%B5452300551227189^HOGAN/PAUL ^08043210000000725000000? 2542353435323330303535313232373138395E484F47414E2F5041554C2020202020205E30383034333231303030303030303732353030303030303F00000000 </code></pre> <hr /> <p><strong>Note:</strong> As you&#8217;re probably already aware, this algorithm is best described using big numbers, which can&#8217;t be represented as literals in some programming languages (like Java or C#). However, many languages have classes that allow you to represent big numbers in other ways (e.g., java.math.BigInteger, System.Numerics.BigInteger). It&#8217;s your job to adapt this algorithm so that it can be represented in your language of choice. Two small problems I encountered were ensuring the correct endianness and signedness were being used (this algorithm requires the byte order to be big endian and that unsigned integers are used). I made a utility class called BigInt to do this for me.</p> <hr /> <p>First, let&#8217;s define a few standard functions:</p> <ul> <li><a href="http://en.wikipedia.org/wiki/Data_Encryption_Standard">DES</a> and <a href="http://en.wikipedia.org/wiki/Triple_DES">Triple DES</a> refer to their respective cryptographic algorithms. Most programming languages have access to some implementation of these ciphers either through OpenSSL or Bouncy Castle. These ciphers are initialized with a zeroed out IV of 8 bytes, they&#8217;re zero-padded, and use Cipher-Block Chaining (CBC). Let&#8217;s define the signatures for these standard functions that&#8217;ll be used throughout this algorithm: <ul> <li><code>DesEncrypt(key, message) -&gt; returns cryptogram</code></li> <li><code>DesDecrypt(key, cryptogram) -&gt; returns message</code></li> <li><code>TripleDesEncrypt(key, message) -&gt; returns cryptogram</code></li> <li><code>TripleDesDecrypt(key, cryptogram) -&gt; returns message</code></li> </ul> </li> </ul> <p>First we must create the IPEK given then KSN and BDK:</p> <pre><code>CreateIpek(ksn, bdk) { return TripleDesEncrypt(bdk, (ksn &amp; KsnMask) &gt;&gt; 16) &lt;&lt; 64 | TripleDesEncrypt(bdk ^ KeyMask, (ksn &amp; KsnMask) &gt;&gt; 16) } </code></pre> <p>Now we can get the IPEK:</p> <pre><code>ipek = CreateIpek(ksn, bdk) = CreateIpek(FFFF9876543210E00008, 0123456789ABCDEFFEDCBA9876543210) = 6AC292FAA1315B4D858AB3A3D7D5933A </code></pre> <p>After that we need a way to get the Session Key (this one is more complicated):</p> <pre><code>CreateSessionKey(ipek, ksn) { return DeriveKey(ipek, ksn) ^ FF00000000000000FF } </code></pre> <p>The DeriveKey method finds the IKSN and generates session keys until it gets to the one that corresponds to the current KSN. We define this method as:</p> <pre><code>DeriveKey(ipek, ksn) { ksnReg = ksn &amp; FFFFFFFFFFE00000 curKey = ipek for (shiftReg = 0x100000; shiftReg &gt; 0; shiftReg &gt;&gt;= 1) if ((shiftReg &amp; ksn &amp; 1FFFFF) &gt; 0) curKey = GenerateKey(curKey, ksnReg |= shiftReg) return curKey } </code></pre> <p>Where the GenerateKey method looks like:</p> <pre><code>GenerateKey(key, ksn) { return EncryptRegister(key ^ KeyMask, ksn) &lt;&lt; 64 | EncryptRegister(key, ksn) } </code></pre> <p>And EncryptRegister looks like:</p> <pre><code>EncryptRegister(key, reg) { return (key &amp; FFFFFFFFFFFFFFFF) ^ DesEncrypt((key &amp; FFFFFFFFFFFFFFFF0000000000000000) &gt;&gt; 64, key &amp; FFFFFFFFFFFFFFFF ^ reg) } </code></pre> <p>Then you can generate the Session Key given the IPEK and KSN:</p> <pre><code>key = CreateSessionKey(ipek, ksn) = CreateSessionKey(6AC292FAA1315B4D858AB3A3D7D5933A, FFFF9876543210E00008) = 27F66D5244FF621EAA6F6120EDEB427F </code></pre> <p>Which can be used to decrypt the cryptogram:</p> <pre><code>message = TripleDesDecrypt(key, cryptogram) = TripleDesDecrypt(27F66D5244FF621EAA6F6120EDEB427F, C25C1D1197D31CAA87285D59A892047426D9182EC11353C051ADD6D0F072A6CB3436560B3071FC1FD11D9F7E74886742D9BEE0CFD1EA1064C213BB55278B2F12) = 2542353435323330303535313232373138395E484F47414E2F5041554C2020202020205E30383034333231303030303030303732353030303030303F00000000 = %B5452300551227189^HOGAN/PAUL ^08043210000000725000000? </code></pre> <p>That&#8217;s it, you&#8217;re done!</p> <span id="wordads-inline-marker" style="display: none;"></span><div id="atatags-702045275-67475fc8781ad"> <script type="text/javascript"> __ATA.cmd.push(function() { __ATA.initVideoSlot('atatags-702045275-67475fc8781ad', { sectionId: '702045275', format: 'inread' }); }); </script> </div> <div id="atatags-702045271-67475fc878203"></div> <script> __ATA.cmd.push(function() { __ATA.initDynamicSlot({ id: 'atatags-702045271-67475fc878203', location: 120, formFactor: '001', label: { text: 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class="screen-reader-text">Post navigation</h2> <div class="nav-links"><div class="nav-previous"><a href="https://arthurvandermerwe.com/2015/05/28/eftpos-initialisation-using-rsa-cryptography/" rel="prev"><span class="meta-nav" aria-hidden="true">Previous Post</span> <span class="screen-reader-text">Previous post:</span> <br/><span class="post-title">EFTPOS Initialisation using RSA&nbsp;Cryptography</span></a></div><div class="nav-next"><a href="https://arthurvandermerwe.com/2015/07/31/the-refund-vulnerability-of-as2805-and-eftpos/" rel="next"><span class="meta-nav" aria-hidden="true">Next Post</span> <span class="screen-reader-text">Next post:</span> <br/><span class="post-title">The Refund vulnerability of AS2805 and&nbsp;EFTPOS</span></a></div></div> </nav> <div id="comments" class="comments-area default-max-width"> <h2 class="comments-title"> 18 Comments </h2><!-- .comments-title --> <ol class="comment-list commentlist"> <li class="comment even thread-even depth-1 parent" id="comment-321"> <div id="div-comment-321" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://0.gravatar.com/avatar/920c40cd110715d8777307c88f5652f1a26743e392a6961629dcc7937926321b?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://0.gravatar.com/avatar/920c40cd110715d8777307c88f5652f1a26743e392a6961629dcc7937926321b?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://0.gravatar.com/avatar/920c40cd110715d8777307c88f5652f1a26743e392a6961629dcc7937926321b?s=63&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://0.gravatar.com/avatar/920c40cd110715d8777307c88f5652f1a26743e392a6961629dcc7937926321b?s=84&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://0.gravatar.com/avatar/920c40cd110715d8777307c88f5652f1a26743e392a6961629dcc7937926321b?s=126&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://0.gravatar.com/avatar/920c40cd110715d8777307c88f5652f1a26743e392a6961629dcc7937926321b?s=168&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn"><a href="http://n/a" class="url" rel="ugc external nofollow">Niall</a></cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-321">December 5, 2016 at 10:08 am</a> </div> <p>Arthur, first off: incredible article, thank you.</p> <p>Two questions:<br /> 1. You supply a single key to the TripleDesEncrypt &#8211; can you provide any insight into how the 3 (or 2?) keys for the three-part DES encryption are generated? do i need to care?<br /> 2. What&#8217;s the value of the KeyMask you use to xor against the BDK during one of the TripleDesEncrypt steps?</p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=321#respond" data-commentid="321" data-postid="138" data-belowelement="div-comment-321" data-respondelement="respond" data-replyto="Reply to Niall" aria-label="Reply to Niall">Reply</a></div> </div> <ol class="children"> <li class="comment byuser comment-author-arthurvdmerwe bypostauthor odd alt depth-2" id="comment-322"> <div id="div-comment-322" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=63&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=84&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=126&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=168&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn"><a href="http://arthurvandermerwe.com" class="url" rel="ugc">arthurvdmerwe</a></cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-322">December 5, 2016 at 10:29 am</a> </div> <p>Hi Niall, here is the C# example for the article. Mask is hardcoded and TDES function is used from the Microsoft crypto library.<br /> <code><br /> using System;<br /> using System.Linq;<br /> using System.Numerics;<br /> using System.Security.Cryptography;</p> <p> public static class Dukpt<br /> {<br /> private static readonly BigInteger Reg3Mask = BigInt.FromHex("1FFFFF");<br /> private static readonly BigInteger ShiftRegMask = BigInt.FromHex("100000");<br /> private static readonly BigInteger Reg8Mask = BigInt.FromHex("FFFFFFFFFFE00000");<br /> private static readonly BigInteger Ls16Mask = BigInt.FromHex("FFFFFFFFFFFFFFFF");<br /> private static readonly BigInteger Ms16Mask = BigInt.FromHex("FFFFFFFFFFFFFFFF0000000000000000");<br /> private static readonly BigInteger KeyMask = BigInt.FromHex("C0C0C0C000000000C0C0C0C000000000");<br /> private static readonly BigInteger PekMask = BigInt.FromHex("FF00000000000000FF");<br /> private static readonly BigInteger KsnMask = BigInt.FromHex("FFFFFFFFFFFFFFE00000");<br /> private static readonly BigInteger DekMask = BigInt.FromHex("0000000000FF00000000000000FF0000"); </p> <p> public static BigInteger CreateBdk(BigInteger key1, BigInteger key2)<br /> {<br /> return key1 ^ key2;<br /> }</p> <p> public static BigInteger CreateIpek(BigInteger ksn, BigInteger bdk)<br /> {<br /> return Transform("TripleDES", true, bdk, (ksn &amp; KsnMask) &gt;&gt; 16) &lt;&gt; 16);<br /> }</p> <p> public static BigInteger CreateSessionKey(BigInteger ipek, BigInteger ksn)<br /> {<br /> return DeriveKey(ipek, ksn) ^ PekMask;<br /> }</p> <p> // Added in the handling for decrypting IDTech tracks<br /> public static BigInteger CreateSessionKeyIdTech(BigInteger ipek, BigInteger ksn) {<br /> var key = DeriveKey(ipek, ksn) ^ DekMask;<br /> return Transform("TripleDES", true, key, (key &amp; Ms16Mask) &gt;&gt; 64) &lt; 0; shiftReg &gt;&gt;= 1)<br /> if ((shiftReg &amp; ksn &amp; Reg3Mask) &gt; 0)<br /> curKey = GenerateKey(curKey, ksnReg |= shiftReg);<br /> return curKey;<br /> }</p> <p> public static BigInteger GenerateKey(BigInteger key, BigInteger ksn)<br /> {<br /> return EncryptRegister(key ^ KeyMask, ksn) &lt;&gt; 64, (curKey &amp; Ls16Mask ^ reg8));<br /> }</p> <p> public static BigInteger Transform(string name, bool encrypt, BigInteger key, BigInteger message)<br /> {<br /> using (var cipher = SymmetricAlgorithm.Create(name))<br /> {<br /> var k = key.GetBytes();</p> <p> // gets the next multiple of 8<br /> cipher.Key = new byte[Math.Max(0, GetNearestWholeMultiple(k.Length, 8) - k.Length)].Concat(key.GetBytes()).ToArray();<br /> cipher.IV = new byte[8];<br /> cipher.Mode = CipherMode.CBC;<br /> cipher.Padding = PaddingMode.Zeros;<br /> using (var crypto = encrypt ? cipher.CreateEncryptor() : cipher.CreateDecryptor())<br /> {<br /> var data = message.GetBytes();<br /> // Added the GetNearestWholeMultiple here.<br /> data = new byte[Math.Max(0, GetNearestWholeMultiple(data.Length, 8) - data.Length)].Concat(message.GetBytes()).ToArray();<br /> return BigInt.FromBytes(crypto.TransformFinalBlock(data, 0, data.Length));<br /> }<br /> }<br /> }</p> <p> // Gets the next multiple of 8<br /> // Works with both scenarios, getting 7 bytes instead of 8 and works when expecting 16 bytes and getting 15.<br /> private static int GetNearestWholeMultiple(decimal input, int multiple)<br /> {<br /> var output = Math.Round(input / multiple);<br /> if (output == 0 &amp;&amp; input &gt; 0) output += 1;<br /> output *= multiple;<br /> return (int)output;<br /> }</p> <p> public static byte[] Encrypt(string bdk, string ksn, byte[] track)<br /> {<br /> return Transform("TripleDES", true, CreateSessionKey(CreateIpek(<br /> BigInt.FromHex(ksn), BigInt.FromHex(bdk)), BigInt.FromHex(ksn)), BigInt.FromBytes(track)).GetBytes();<br /> }</p> <p> public static byte[] Decrypt(string bdk, string ksn, byte[] track)<br /> {<br /> return Transform("TripleDES", false, CreateSessionKey(CreateIpek(<br /> BigInt.FromHex(ksn), BigInt.FromHex(bdk)), BigInt.FromHex(ksn)), BigInt.FromBytes(track)).GetBytes();<br /> }</p> <p> public static byte[] DecryptIdTech(string bdk, string ksn, byte[] track)<br /> {<br /> return Transform("TripleDES", false, CreateSessionKeyIdTech(CreateIpek(<br /> BigInt.FromHex(ksn), BigInt.FromHex(bdk)), BigInt.FromHex(ksn)), BigInt.FromBytes(track)).GetBytes();<br /> }<br /> }<br /> public static class BigInt<br /> {</p> <p> public static BigInteger FromHex(string hex)<br /> {<br /> return BigInteger.Parse("00" + hex, System.Globalization.NumberStyles.HexNumber);<br /> }</p> <p> public static BigInteger FromBytes(byte[] bytes)<br /> {<br /> return new BigInteger(bytes.Reverse().Concat(new byte[] { 0 }).ToArray());<br /> }</p> <p> public static byte[] GetBytes(this BigInteger number)<br /> {<br /> return number.ToByteArray().Reverse().SkipWhile(b =&gt; b == 0).ToArray();<br /> }<br /> }<br /> }</code></p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=322#respond" data-commentid="322" data-postid="138" data-belowelement="div-comment-322" data-respondelement="respond" data-replyto="Reply to arthurvdmerwe" aria-label="Reply to arthurvdmerwe">Reply</a></div> </div> </li><!-- #comment-## --> </ol><!-- .children --> </li><!-- #comment-## --> <li class="comment byuser comment-author-arthurvdmerwe bypostauthor even thread-odd thread-alt depth-1 parent" id="comment-323"> <div id="div-comment-323" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=63&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=84&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=126&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=168&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn"><a href="http://arthurvandermerwe.com" class="url" rel="ugc">arthurvdmerwe</a></cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-323">December 5, 2016 at 10:33 am</a> </div> <p>example of the usage of the code:<br /> var test = &#8220;%B5452300551227189^HOGAN/PAUL ^08043210000000725000000?\0\0\0\0&#8221;;</p> <p>// Decrypting<br /> var bdk = &#8220;0123456789ABCDEFFEDCBA9876543210&#8221;;<br /> var ksn = &#8220;FFFF9876543210E00008&#8221;;<br /> var track = &#8220;C25C1D1197D31CAA87285D59A892047426D9182EC11353C051ADD6D0F072A6CB3436560B3071FC1FD11D9F7E74886742D9BEE0CFD1EA1064C213BB55278B2F12&#8221;;<br /> var decBytes = Dukpt.Decrypt(bdk, ksn, BigInt.FromHex(track).GetBytes());<br /> var decrypted = Encoding.UTF8.GetString(decBytes);<br /> Console.WriteLine(decrypted == test); // True</p> <p>// Encrypting<br /> var encBytes = Dukpt.Encrypt(bdk, ksn, decBytes);<br /> var encrypted = BitConverter.ToString(encBytes).Replace(&#8220;-&#8220;, &#8220;&#8221;);<br /> Console.WriteLine(encrypted == track); // True</p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=323#respond" data-commentid="323" data-postid="138" data-belowelement="div-comment-323" data-respondelement="respond" data-replyto="Reply to arthurvdmerwe" aria-label="Reply to arthurvdmerwe">Reply</a></div> </div> <ol class="children"> <li class="comment odd alt depth-2" id="comment-324"> <div id="div-comment-324" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://0.gravatar.com/avatar/920c40cd110715d8777307c88f5652f1a26743e392a6961629dcc7937926321b?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://0.gravatar.com/avatar/920c40cd110715d8777307c88f5652f1a26743e392a6961629dcc7937926321b?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://0.gravatar.com/avatar/920c40cd110715d8777307c88f5652f1a26743e392a6961629dcc7937926321b?s=63&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://0.gravatar.com/avatar/920c40cd110715d8777307c88f5652f1a26743e392a6961629dcc7937926321b?s=84&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://0.gravatar.com/avatar/920c40cd110715d8777307c88f5652f1a26743e392a6961629dcc7937926321b?s=126&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://0.gravatar.com/avatar/920c40cd110715d8777307c88f5652f1a26743e392a6961629dcc7937926321b?s=168&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn"><a href="http://n/a" class="url" rel="ugc external nofollow">Niall</a></cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-324">December 5, 2016 at 12:09 pm</a> </div> <p>You complete legend, thank you very much indeed!<br /> epic kupos to you &#8211; this gear is a total head melt but you&#8217;ve explained it incredibly well.</p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=324#respond" data-commentid="324" data-postid="138" data-belowelement="div-comment-324" data-respondelement="respond" data-replyto="Reply to Niall" aria-label="Reply to Niall">Reply</a></div> </div> </li><!-- #comment-## --> </ol><!-- .children --> </li><!-- #comment-## --> <li class="comment byuser comment-author-pankajpatil96 even thread-even depth-1 parent" id="comment-325"> <div id="div-comment-325" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://1.gravatar.com/avatar/dae2f9de57a7c28eab803aab9ac4b1865c46cd1eafe116fb5b9a10e57301ef17?s=42&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://1.gravatar.com/avatar/dae2f9de57a7c28eab803aab9ac4b1865c46cd1eafe116fb5b9a10e57301ef17?s=42&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://1.gravatar.com/avatar/dae2f9de57a7c28eab803aab9ac4b1865c46cd1eafe116fb5b9a10e57301ef17?s=63&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://1.gravatar.com/avatar/dae2f9de57a7c28eab803aab9ac4b1865c46cd1eafe116fb5b9a10e57301ef17?s=84&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://1.gravatar.com/avatar/dae2f9de57a7c28eab803aab9ac4b1865c46cd1eafe116fb5b9a10e57301ef17?s=126&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://1.gravatar.com/avatar/dae2f9de57a7c28eab803aab9ac4b1865c46cd1eafe116fb5b9a10e57301ef17?s=168&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn">Pankaj Patil's Blog</cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-325">December 9, 2016 at 11:26 pm</a> </div> <p>Can you please provide the Java Implementation of the Same.</p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=325#respond" data-commentid="325" data-postid="138" data-belowelement="div-comment-325" data-respondelement="respond" data-replyto="Reply to Pankaj Patil&#039;s Blog" aria-label="Reply to Pankaj Patil&#039;s Blog">Reply</a></div> </div> <ol class="children"> <li class="comment odd alt depth-2" id="comment-327"> <div id="div-comment-327" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://1.gravatar.com/avatar/14f0fce6e24ec0917a2b8a67f95d3b0e5b34df0bf0c6e04a6410e8003930dc88?s=42&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://1.gravatar.com/avatar/14f0fce6e24ec0917a2b8a67f95d3b0e5b34df0bf0c6e04a6410e8003930dc88?s=42&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://1.gravatar.com/avatar/14f0fce6e24ec0917a2b8a67f95d3b0e5b34df0bf0c6e04a6410e8003930dc88?s=63&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://1.gravatar.com/avatar/14f0fce6e24ec0917a2b8a67f95d3b0e5b34df0bf0c6e04a6410e8003930dc88?s=84&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://1.gravatar.com/avatar/14f0fce6e24ec0917a2b8a67f95d3b0e5b34df0bf0c6e04a6410e8003930dc88?s=126&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://1.gravatar.com/avatar/14f0fce6e24ec0917a2b8a67f95d3b0e5b34df0bf0c6e04a6410e8003930dc88?s=168&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn"><a href="http://gravatar.com/yashcomplex" class="url" rel="ugc external nofollow">Yash Jain</a></cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-327">December 12, 2016 at 12:32 am</a> </div> <p>Did you get the Java implementation of the same then please share the same.</p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=327#respond" data-commentid="327" data-postid="138" data-belowelement="div-comment-327" data-respondelement="respond" data-replyto="Reply to Yash Jain" aria-label="Reply to Yash Jain">Reply</a></div> </div> </li><!-- #comment-## --> <li class="comment byuser comment-author-yashcomplex even depth-2 parent" id="comment-328"> <div id="div-comment-328" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://1.gravatar.com/avatar/14f0fce6e24ec0917a2b8a67f95d3b0e5b34df0bf0c6e04a6410e8003930dc88?s=42&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://1.gravatar.com/avatar/14f0fce6e24ec0917a2b8a67f95d3b0e5b34df0bf0c6e04a6410e8003930dc88?s=42&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://1.gravatar.com/avatar/14f0fce6e24ec0917a2b8a67f95d3b0e5b34df0bf0c6e04a6410e8003930dc88?s=63&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://1.gravatar.com/avatar/14f0fce6e24ec0917a2b8a67f95d3b0e5b34df0bf0c6e04a6410e8003930dc88?s=84&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://1.gravatar.com/avatar/14f0fce6e24ec0917a2b8a67f95d3b0e5b34df0bf0c6e04a6410e8003930dc88?s=126&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://1.gravatar.com/avatar/14f0fce6e24ec0917a2b8a67f95d3b0e5b34df0bf0c6e04a6410e8003930dc88?s=168&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn"><a href="http://yashcomplex.wordpress.com" class="url" rel="ugc external nofollow">yashcomplex</a></cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-328">December 12, 2016 at 12:33 am</a> </div> <p>In case if you have got the java implementation of the same then please share with me @email <a href="mailto:yashcomplex@gmail.com">yashcomplex@gmail.com</a></p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=328#respond" data-commentid="328" data-postid="138" data-belowelement="div-comment-328" data-respondelement="respond" data-replyto="Reply to yashcomplex" aria-label="Reply to yashcomplex">Reply</a></div> </div> <ol class="children"> <li class="comment byuser comment-author-arthurvdmerwe bypostauthor odd alt depth-3" id="comment-330"> <div id="div-comment-330" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=63&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=84&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=126&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=168&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn"><a href="http://arthurvandermerwe.com" class="url" rel="ugc">arthurvdmerwe</a></cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-330">December 12, 2016 at 10:35 am</a> </div> <p>Sorry, You would need to make your own Java implementation.</p> </div> </li><!-- #comment-## --> </ol><!-- .children --> </li><!-- #comment-## --> <li class="comment even depth-2" id="comment-555"> <div id="div-comment-555" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://1.gravatar.com/avatar/d546f77cb2ee03acd96302994fef65eea1cc00241470b6df8fde88d558c86d1c?s=42&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://1.gravatar.com/avatar/d546f77cb2ee03acd96302994fef65eea1cc00241470b6df8fde88d558c86d1c?s=42&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://1.gravatar.com/avatar/d546f77cb2ee03acd96302994fef65eea1cc00241470b6df8fde88d558c86d1c?s=63&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://1.gravatar.com/avatar/d546f77cb2ee03acd96302994fef65eea1cc00241470b6df8fde88d558c86d1c?s=84&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://1.gravatar.com/avatar/d546f77cb2ee03acd96302994fef65eea1cc00241470b6df8fde88d558c86d1c?s=126&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://1.gravatar.com/avatar/d546f77cb2ee03acd96302994fef65eea1cc00241470b6df8fde88d558c86d1c?s=168&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn">Ashish Kumar</cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-555">March 29, 2018 at 4:20 am</a> </div> <p>brother if u got the implementation of java code of the same .then plz share me.<br /> Thanks in advance.</p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=555#respond" data-commentid="555" data-postid="138" data-belowelement="div-comment-555" data-respondelement="respond" data-replyto="Reply to Ashish Kumar" aria-label="Reply to Ashish Kumar">Reply</a></div> </div> </li><!-- #comment-## --> </ol><!-- .children --> </li><!-- #comment-## --> <li class="comment odd alt thread-odd thread-alt depth-1 parent" id="comment-364"> <div id="div-comment-364" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://1.gravatar.com/avatar/a71d24f62efb65bd71029f161b37e82af7e7a62cf387bc23913fcdd050955d4c?s=42&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://1.gravatar.com/avatar/a71d24f62efb65bd71029f161b37e82af7e7a62cf387bc23913fcdd050955d4c?s=42&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://1.gravatar.com/avatar/a71d24f62efb65bd71029f161b37e82af7e7a62cf387bc23913fcdd050955d4c?s=63&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://1.gravatar.com/avatar/a71d24f62efb65bd71029f161b37e82af7e7a62cf387bc23913fcdd050955d4c?s=84&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://1.gravatar.com/avatar/a71d24f62efb65bd71029f161b37e82af7e7a62cf387bc23913fcdd050955d4c?s=126&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://1.gravatar.com/avatar/a71d24f62efb65bd71029f161b37e82af7e7a62cf387bc23913fcdd050955d4c?s=168&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn"><a href="http://no%20website" class="url" rel="ugc external nofollow">Krishna Telgave</a></cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-364">March 20, 2017 at 1:56 am</a> </div> <p>Great Article.<br /> Can you please help regarding DUKPT PINBLOCK Decryption.</p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=364#respond" data-commentid="364" data-postid="138" data-belowelement="div-comment-364" data-respondelement="respond" data-replyto="Reply to Krishna Telgave" aria-label="Reply to Krishna Telgave">Reply</a></div> </div> <ol class="children"> <li class="comment byuser comment-author-arthurvdmerwe bypostauthor even depth-2 parent" id="comment-365"> <div id="div-comment-365" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=63&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=84&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=126&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=168&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn"><a href="http://arthurvandermerwe.com" class="url" rel="ugc">arthurvdmerwe</a></cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-365">March 21, 2017 at 5:40 pm</a> </div> <p>Hi Krishna, cannot at the moment unfortunately have to much work.</p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=365#respond" data-commentid="365" data-postid="138" data-belowelement="div-comment-365" data-respondelement="respond" data-replyto="Reply to arthurvdmerwe" aria-label="Reply to arthurvdmerwe">Reply</a></div> </div> <ol class="children"> <li class="comment odd alt depth-3" id="comment-366"> <div id="div-comment-366" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://0.gravatar.com/avatar/ad516503a11cd5ca435acc9bb6523536?s=42' srcset='https://0.gravatar.com/avatar/ad516503a11cd5ca435acc9bb6523536?s=42 1x, https://0.gravatar.com/avatar/ad516503a11cd5ca435acc9bb6523536?s=63 1.5x, https://0.gravatar.com/avatar/ad516503a11cd5ca435acc9bb6523536?s=84 2x, https://0.gravatar.com/avatar/ad516503a11cd5ca435acc9bb6523536?s=126 3x, https://0.gravatar.com/avatar/ad516503a11cd5ca435acc9bb6523536?s=168 4x' class='avatar avatar-42 avatar-default' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn">Anonymous</cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-366">March 22, 2017 at 1:17 am</a> </div> <p>Thanks anyway. I have successfully decrypted DUKPT PIN.</p> </div> </li><!-- #comment-## --> <li class="comment even depth-3" id="comment-367"> <div id="div-comment-367" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://1.gravatar.com/avatar/a71d24f62efb65bd71029f161b37e82af7e7a62cf387bc23913fcdd050955d4c?s=42&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://1.gravatar.com/avatar/a71d24f62efb65bd71029f161b37e82af7e7a62cf387bc23913fcdd050955d4c?s=42&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://1.gravatar.com/avatar/a71d24f62efb65bd71029f161b37e82af7e7a62cf387bc23913fcdd050955d4c?s=63&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://1.gravatar.com/avatar/a71d24f62efb65bd71029f161b37e82af7e7a62cf387bc23913fcdd050955d4c?s=84&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://1.gravatar.com/avatar/a71d24f62efb65bd71029f161b37e82af7e7a62cf387bc23913fcdd050955d4c?s=126&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://1.gravatar.com/avatar/a71d24f62efb65bd71029f161b37e82af7e7a62cf387bc23913fcdd050955d4c?s=168&#038;d=https%3A%2F%2F1.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn">Krishna Telgave</cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-367">March 22, 2017 at 1:18 am</a> </div> <p>Thanks anyway. i have successfully decrypted DUKPT Pinblock.</p> </div> </li><!-- #comment-## --> </ol><!-- .children --> </li><!-- #comment-## --> </ol><!-- .children --> </li><!-- #comment-## --> <li class="comment odd alt thread-even depth-1" id="comment-814"> <div id="div-comment-814" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://i0.wp.com/pbs.twimg.com/profile_images/378800000414742385/e11e6436c9b51b27e41a0f139d5a2010_normal.jpeg?resize=42%2C42&#038;ssl=1' srcset='https://i0.wp.com/pbs.twimg.com/profile_images/378800000414742385/e11e6436c9b51b27e41a0f139d5a2010_normal.jpeg?resize=42%2C42&#038;ssl=1 1x, https://i0.wp.com/pbs.twimg.com/profile_images/378800000414742385/e11e6436c9b51b27e41a0f139d5a2010_normal.jpeg?resize=63%2C63&#038;ssl=1 1.5x, https://i0.wp.com/pbs.twimg.com/profile_images/378800000414742385/e11e6436c9b51b27e41a0f139d5a2010_normal.jpeg?resize=84%2C84&#038;ssl=1 2x, https://i0.wp.com/pbs.twimg.com/profile_images/378800000414742385/e11e6436c9b51b27e41a0f139d5a2010_normal.jpeg?resize=126%2C126&#038;ssl=1 3x, https://i0.wp.com/pbs.twimg.com/profile_images/378800000414742385/e11e6436c9b51b27e41a0f139d5a2010_normal.jpeg?resize=168%2C168&#038;ssl=1 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn"><a href="http://twitter.com/kishorekollucse" class="url" rel="ugc external nofollow">kishore.k (@kishorekollucse)</a></cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-814">June 6, 2019 at 5:01 pm</a> </div> <p>Can you please help regarding DUKPT PINBLOCK Decryption.</p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=814#respond" data-commentid="814" data-postid="138" data-belowelement="div-comment-814" data-respondelement="respond" data-replyto="Reply to kishore.k (@kishorekollucse)" aria-label="Reply to kishore.k (@kishorekollucse)">Reply</a></div> </div> </li><!-- #comment-## --> <li class="comment even thread-odd thread-alt depth-1 parent" id="comment-1568"> <div id="div-comment-1568" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://2.gravatar.com/avatar/26b20d19ec05beaa1f57181721e038c4db24d4f7cb77a5d307a5fcf928bfa12b?s=42&#038;d=https%3A%2F%2F2.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://2.gravatar.com/avatar/26b20d19ec05beaa1f57181721e038c4db24d4f7cb77a5d307a5fcf928bfa12b?s=42&#038;d=https%3A%2F%2F2.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://2.gravatar.com/avatar/26b20d19ec05beaa1f57181721e038c4db24d4f7cb77a5d307a5fcf928bfa12b?s=63&#038;d=https%3A%2F%2F2.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://2.gravatar.com/avatar/26b20d19ec05beaa1f57181721e038c4db24d4f7cb77a5d307a5fcf928bfa12b?s=84&#038;d=https%3A%2F%2F2.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://2.gravatar.com/avatar/26b20d19ec05beaa1f57181721e038c4db24d4f7cb77a5d307a5fcf928bfa12b?s=126&#038;d=https%3A%2F%2F2.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://2.gravatar.com/avatar/26b20d19ec05beaa1f57181721e038c4db24d4f7cb77a5d307a5fcf928bfa12b?s=168&#038;d=https%3A%2F%2F2.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn">Do An</cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-1568">August 20, 2021 at 2:48 pm</a> </div> <p>i just got an pay shield 9000 could u show me how i save a BDK to my HSM? Thanks you.</p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=1568#respond" data-commentid="1568" data-postid="138" data-belowelement="div-comment-1568" data-respondelement="respond" data-replyto="Reply to Do An" aria-label="Reply to Do An">Reply</a></div> </div> <ol class="children"> <li class="comment byuser comment-author-arthurvdmerwe bypostauthor odd alt depth-2" id="comment-1706"> <div id="div-comment-1706" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=63&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=84&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=126&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=168&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn"><a href="http://arthurvandermerwe.com" class="url" rel="ugc">arthurvdmerwe</a></cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-1706">March 18, 2022 at 11:11 am</a> </div> <p>You will need to generate a BDK (A0 Command), and export it under the LMK. You do not save it to the HSM.</p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=1706#respond" data-commentid="1706" data-postid="138" data-belowelement="div-comment-1706" data-respondelement="respond" data-replyto="Reply to arthurvdmerwe" aria-label="Reply to arthurvdmerwe">Reply</a></div> </div> </li><!-- #comment-## --> </ol><!-- .children --> </li><!-- #comment-## --> <li class="comment even thread-even depth-1 parent" id="comment-1700"> <div id="div-comment-1700" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://0.gravatar.com/avatar/c29edea55ba13c7514a235276834b68785fb5ab804afe3b95297e33405470b0c?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://0.gravatar.com/avatar/c29edea55ba13c7514a235276834b68785fb5ab804afe3b95297e33405470b0c?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://0.gravatar.com/avatar/c29edea55ba13c7514a235276834b68785fb5ab804afe3b95297e33405470b0c?s=63&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://0.gravatar.com/avatar/c29edea55ba13c7514a235276834b68785fb5ab804afe3b95297e33405470b0c?s=84&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://0.gravatar.com/avatar/c29edea55ba13c7514a235276834b68785fb5ab804afe3b95297e33405470b0c?s=126&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://0.gravatar.com/avatar/c29edea55ba13c7514a235276834b68785fb5ab804afe3b95297e33405470b0c?s=168&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn">Harold P</cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-1700">March 4, 2022 at 6:20 am</a> </div> <p>Hi Arthur,<br /> very useful post, thanks. I have a doubt, my boss want to Obtain BDK from a IPEK and KSN, Is it Possible ? Do you have any reference about this? </p> <p>thanks a lot bro.</p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=1700#respond" data-commentid="1700" data-postid="138" data-belowelement="div-comment-1700" data-respondelement="respond" data-replyto="Reply to Harold P" aria-label="Reply to Harold P">Reply</a></div> </div> <ol class="children"> <li class="comment byuser comment-author-arthurvdmerwe bypostauthor odd alt depth-2" id="comment-1704"> <div id="div-comment-1704" class="comment-body"> <div class="comment-author vcard"> <img alt='' src='https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G' srcset='https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=42&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D42&#038;r=G 1x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=63&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D63&#038;r=G 1.5x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=84&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D84&#038;r=G 2x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=126&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D126&#038;r=G 3x, https://0.gravatar.com/avatar/348f4a382f4bf6e3e47950e950b68a777ca8894f20fdde38ad1073656a2f5f63?s=168&#038;d=https%3A%2F%2F0.gravatar.com%2Favatar%2Fad516503a11cd5ca435acc9bb6523536%3Fs%3D168&#038;r=G 4x' class='avatar avatar-42' height='42' width='42' loading='lazy' decoding='async' /> <cite class="fn"><a href="http://arthurvandermerwe.com" class="url" rel="ugc">arthurvdmerwe</a></cite> <span class="says">says:</span> </div> <div class="comment-meta commentmetadata"> <a href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/#comment-1704">March 18, 2022 at 10:51 am</a> </div> <p>This is not possible. The BDK encrypts the KSN; the ciphertext is the IPEK. i.e. $E_{BDK}(KSN) = IPEK$. Retrieving the BDK is equivalent to breaking the encryption scheme and deriving the key. </p> <div class="reply"><a rel="nofollow" class="comment-reply-link" href="https://arthurvandermerwe.com/2015/05/30/dukpt-explained-with-examples/?replytocom=1704#respond" data-commentid="1704" data-postid="138" data-belowelement="div-comment-1704" data-respondelement="respond" data-replyto="Reply to arthurvdmerwe" aria-label="Reply to arthurvdmerwe">Reply</a></div> </div> </li><!-- #comment-## --> </ol><!-- .children --> </li><!-- #comment-## --> </ol><!-- .comment-list --> <div id="respond" class="comment-respond"> <h3 id="reply-title" class="comment-reply-title">Leave a Comment <small><a rel="nofollow" id="cancel-comment-reply-link" href="/2015/05/30/dukpt-explained-with-examples/#respond" style="display:none;">Cancel reply</a></small></h3><form action="https://arthurvandermerwe.com/wp-comments-post.php" method="post" id="commentform" class="comment-form" novalidate> <div id="comment-form__verbum" class="transparent"></div><div class="verbum-form-meta"><input type='hidden' name='comment_post_ID' value='138' id='comment_post_ID' /> <input type='hidden' name='comment_parent' id='comment_parent' value='0' /> <input type="hidden" name="highlander_comment_nonce" id="highlander_comment_nonce" value="b7f90b704e" /> <input type="hidden" name="verbum_show_subscription_modal" value="" /></div><p style="display: none;"><input type="hidden" id="akismet_comment_nonce" name="akismet_comment_nonce" value="79f1d10d4f" /></p><p style="display: none !important;" class="akismet-fields-container" data-prefix="ak_"><label>&#916;<textarea name="ak_hp_textarea" cols="45" rows="8" maxlength="100"></textarea></label><input type="hidden" id="ak_js_1" name="ak_js" value="246"/><script>document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() );</script></p></form> </div><!-- #respond --> </div><!-- #comments --> </main><!-- #main --> </section><!-- #primary --> </div><!-- #content --> <footer id="colophon" class="site-footer default-max-width" role="contentinfo" aria-label="Footer"> <div class="widget-area"> <div class="widget-column footer-widget-1"> <section id="recent-posts-4" class="widget widget_recent_entries"> <h2 class="widget-title">Recent Posts</h2><nav aria-label="Recent Posts"> <ul> <li> <a href="https://arthurvandermerwe.com/2020/02/16/a-brief-comparison-of-as2805-and-key-blocks/">A brief comparison of AS2805 and (TR-31) Key&nbsp;Blocks</a> </li> <li> <a href="https://arthurvandermerwe.com/2020/01/19/what-is-the-random-oracle-model-and-why-should-you-care-part-5-a-few-thoughts-on-cryptographic-engineering/">What is the random oracle model and why should you care? 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