sgbj / dukpt.net Goto Github PK

Hey @sgbj - This is a question, not an issue, if you have time for it. I'm working to port this library to WinRT so that I can use it in an app I'm creating. WinRT uses a new cryptography API that's different than the one that ships with .Net 4.5. One difference that I've found is that the 3DES implementation in WinRT apparently doesn't support a 16-byte key. Passing a 16-byte key to the function that creates the key throws an ArgumentException, "Value does not fall in expected range." If I expand it to a 24-byte key, padding the extra 8 bytes with zeros, it no longer throws an exception but the encrypted value is larger than the one produced by the 16-byte key and the rest of the algorithm doesn't produce the correct result. Do you have any thoughts/insights that could point me in the right direction? Thanks!

I have use this algorithm for magtek uDynamo and it is working great but now i have magtek mini pro and i am getting blob data after swiping. Could you please tell me what process i need to follow to decrypt that blob data.

Actually, I want to get complete card number. when we swiped card with magtek device . is it possible to get it. so please tell me the whole procedure for that.

Thanks for all the explanation. You made the libraries look pretty simple.

But while testing (No changes made to the code), could not get this program work for inputs which are having both track1 and track 2 information. It may not be related to having both track info, but it is not working for below inputs.

track = "670d1456491444377905ab458d2ad9d900d652d661ae7adbc9847f9f63c681c45a065fb47497a970abdc5ad267fd9c6f341ae8f4fe15514a639a6d3611450a537ceea909a60fbc8ecc7c4a0b50dc58fbb024caa90e3a5f97536524276a749767efc62d8e8bcc03bf2bca8e00c5c3719c3fff1a5819233038"

bdk = "0123456789ABCDEFFEDCBA9876543210"
ksn = "00000415130001e00007"

Encrypted and decrypted results are not matching.

//Expected results:
track1Decrypted = "%B4518341234567894^TEST/CARD ^2507201134160000000000819000000?"

track2Decrypted = ";4518341234567894=25072011341681900000?"

Thanks for the great library. On the previous version, we could use:

BigInt.FromHex(track).GetBytes();

on version 2, it looks like it's changed to:

track.HexToBigInteger().GetBytes();

Can you confirm this is the intended behavior? After upgrading to v2, HexToBigInteger() is not accessible. I think it may be related to StringExtensions is an internal class.

Hi ..

I have successfully done the decrypt and encrypt operation. now i need the CVV number for to disply into the GUI.

How can i get the CVV number for IDTech SecureMag Reader..

Kindly help me

I am using this key: 895250336175515C4120CF45F41ABF1C
and this ksn : 62994901190000000003

this is the encrypted data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

I can't get it to work, please advise

we have magtek device and company provided document for generating key is key component- conveyance form which have key component details, and i want to know how we generate this BDK key with these information.

@sgbj - thanks for your work on this project and for sharing it. It's been one of the most useful things I've found as I've researched DUKPT. Could you add a license to this project so I can use it in my work?

Hi,
Wondering if you could help me, I am trying to add the ability to decrypt the ID tech.
I am following their instructions but cant seem to get it to work.
Here is the excerpt from IDtech:
"The key management scheme is DUKPT. For DUKPT, the key used for encrypting data is called the Data Key. Data Key is generated by first taking the DUKPT Derived Key exclusive or’ed with 0000000000FF00000000000000FF0000 to get the resulting intermediate variant key. The left side of the intermediate variant key is then TDES encrypted with the entire 16-byte variant as the key. After the same steps are preformed for the right side of the key, combine the two key parts to create the Data Key."

The method i am modifying is CreatesessionKey

        public static BigInteger CreateSessionKey(BigInteger ipek, BigInteger ksn, bool IDTECH)
        {
            if (IDTECH)
            {
                var curKey = DeriveKey(ipek, ksn) ^ DEK_MASK;

                return BigInt.FromHex(Transform("TripleDES", true, curKey, ((curKey & Ms16Mask) >> 64)).ToString("x") +
                    Transform("TripleDES", true, curKey, (curKey & Ls16Mask)).ToString("x"));


            }
            else
            {
                return DeriveKey(ipek, ksn) ^ PekMask;
            }
        }

hi
Actually , in my side encryption and decryption of card details or track1 and track2 details is correct.
but after decryption process i am unable to find out which card is swiped . So please give me the resolution for that how i am verify card type from decrypted track1 or track2 details.

Found another issue:
If the enrypted track begins with 00 you get the following error.
Length of the data to decrypt is invalid.
It was getting 39 bytes instead of 40

To Fix the Issue i used the GetNearestWholeMultiple method from issue #5 .

i did the following

public static BigInteger Transform(string name, bool encrypt, BigInteger key, BigInteger message)
        {
            using (var cipher = SymmetricAlgorithm.Create(name))
            {
                var k = key.GetBytes();
                cipher.Key = new byte[Math.Max(0, GetNearestWholeMultiple(k.Length, 8) - k.Length)].Concat(key.GetBytes()).ToArray();
                cipher.IV = new byte[8];
                cipher.Mode = CipherMode.CBC;
                cipher.Padding = PaddingMode.Zeros;
                using (var crypto = encrypt ? cipher.CreateEncryptor() : cipher.CreateDecryptor())
                {
                    var data = message.GetBytes();
//Added the GetNearestWholeMultiple here.
                    data = new byte[Math.Max(0, GetNearestWholeMultiple(data.Length, 8) - data.Length)].Concat(message.GetBytes()).ToArray();
                    return BigInt.FromBytes(crypto.TransformFinalBlock(data, 0, data.Length));
                }
            }
        }

They removed "System.Security.Cryptography" and replaced it with "Windows​.Security​.Cryptography", which has a different API and the data types are all different.

Will you add a NuGet package anytime soon? If you want, I can create the NuSpec & hook it up through MyGet.

var decBytes = Dukpt.Decrypt(bdk, ksn, BigInt.FromHex( TRACK ).GetBytes());

where TRACK data is 70 characters length. and i am getting exception in

public static BigInteger Transform() function.

exactly in this line - return BigInt.FromBytes(crypto.TransformFinalBlock(data, 0, data.Length));

Kindly help me to solve this issue.

I occasionally get the following error "Specified key is not a valid size for this algorithm".
When it happens it occurs on the Transform method the key is getting 7 bytes instead of 8.

I have been trying to use the library, but not even the example works, It says the BigInt.Parse has not been implemented. Could be that possible? Why? What should I do?