ChangeReferenceDataCommand Class

Namespace: Yubico.YubiKey.Piv.Commands Assembly: Yubico.YubiKey.dll

Change the PIN or PUK.

C#
public sealed class ChangeReferenceDataCommand : IYubiKeyCommand<ChangeReferenceDataResponse>
Inheritance object ChangeReferenceDataCommand

Remarks

The partner Response class is ChangeReferenceDataResponse.

The PIN starts out as a default value: "123456", which in ASCII is the 6-byte sequence 0x31 32 33 34 35 36. The PUK (PIN Unblocking Key) starts out as a default value as well: "12345678", which in ASCII is the 8-byte sequence 0x31 32 33 34 35 36 37 38. Generally, the first thing done when a YubiKey is initialized for PIV is to change the PIN and PUK (along with the management key). The PIN and PUK are both allowed to be 6 to 8 characters/bytes. The PIN can be any ASCII character. For YubiKeys with firmware versions prior to 5.7, the PUK is allowed to be any character in the 0x00 - 0xFF range for a total length of 6-8 bytes. For YubiKeys with firmware version 5.7 and above, the PUK is allowed to be any character in the 0x00 - 0x7F range for a total length of 6-8 Unicode code points. Since the PIN and PUK are generally input from a keyboard, they are usually made up of ASCII characters.

When you pass a PIN or PUK to this class (the PIN or PUK to change, along with the new value), the class will copy a reference to the object passed in, it will not copy the value. Because of this, you cannot overwrite the PIN until this object is done with it. It will be safe to overwrite the PIN after calling connection.SendCommand. See the User's Manual entry on sensitive data for more information on this topic.

Example: 

using System.Security.Cryptography;
/* This example assumes the application has a method to collect a
 * PIN/PUK.
 */
byte[] oldPuk;
byte[] newPuk;

IYubiKeyConnection connection = key.Connect(YubiKeyApplication.Piv);
oldPuk = CollectPuk();
newPuk = CollectNewPuk();
var changeReferenceDataCommand =
    new ChangeReferenceDataCommand(PivSlot.Puk, oldPuk, newPuk);
ChangeReferenceDataResponse changeReferenceDataResponse =
    connection.SendCommand(changeReferenceDataCommand);
if (changeReferenceDataResponse.Status != ResponseStatus.Success)
{
  if (resetRetryResponse.Status == ResponseStatus.AuthenticationRequired)
  {
      int retryCount = resetRetryResponse.GetData();
      /* report the retry count */
  }
  else
  {
      // Handle error
  }
}

CryptographicOperations.ZeroMemory(puk);
CryptographicOperations.ZeroMemory(newPuk);

Constructors

Name Description
ChangeReferenceDataCommand(byte, ReadOnlyMemory<byte>, ReadOnlyMemory<byte>)

Build a new Command object to "change reference data", which means to change a PIN or PUK.

Properties

Name Description
Application

Gets the YubiKeyApplication to which this command belongs. For this command it's PIV.
SlotNumber

The slot for the PIN or PUK.

Methods

Name Description
CreateCommandApdu()

Creates a well-formed CommandApdu to send to the YubiKey.
CreateResponseForApdu(ResponseApdu)

Creates the corresponding IYubiKeyResponse implementation for the current command.