/// <summary>
/// Reads the selected PCR Index of the TPM.
/// </summary>
/// <param name="pcrIndex">PCR Index 0 - 23</param>
/// <returns>20-byte hex value in a string</returns>
internal string ReadPCR(int pcrIndex)
{
if (pcrIndex < 0 || pcrIndex > 23)
{
throw new ArgumentOutOfRangeException("pcrIndex", "Invalid TPM PCR Index");
}
string cmd = @"00c1" // tag = TPM_TAG_RQU_COMMAND
+ @"0000000e" // paramSize
+ @"00000015" // ordinal = TPM_ORD_PCRRead
+ pcrIndex.ToString("X8");
byte[] res = this.SubmitCommand(HexFormat.StringToByteArray(cmd), 30);
if (res != null)
{
string sRes = HexFormat.ByteArrayToString(res);
//string tag = sRes.Substring(0, 4);
//string paramSize = sRes.Substring(4, 8);
string returnCode = sRes.Substring(12, 8);
string outDigest = sRes.Substring(20, 40);
int rc = Int32.Parse(returnCode, System.Globalization.NumberStyles.HexNumber);
if (rc == 0)
{
return(outDigest);
}
}
return(null);
}
internal string Generate()
{
if (bParamsChanged)
{
string value = null;
StringBuilder sbValues = new StringBuilder();
foreach (WMIQueryObj wmiQuery in this.queryItems)
{
ManagementObjectSearcher oWMI = new ManagementObjectSearcher(wmiQuery.QueryString);
foreach (ManagementObject mo in oWMI.Get())
{
value = (string)mo[wmiQuery.Property];
if (!String.IsNullOrEmpty(value))
{
sbValues.AppendLine(value);
}
}
}
if (MeasureTpm)
{
value = TpmWrapper.Instance.ReadPCR(0);
if (!String.IsNullOrEmpty(value))
{
sbValues.AppendLine(value);
}
else
{
this.bMeasureTpm = false;
}
}
if (MeasureHDDSerialNumber)
{
string logicalDiskId = Path.GetPathRoot(Environment.GetFolderPath(Environment.SpecialFolder.System)).Substring(0, 2);
string deviceSerialNumber = string.Empty;
var query = "ASSOCIATORS OF {Win32_LogicalDisk.DeviceID='" + logicalDiskId + "'} WHERE AssocClass = Win32_LogicalDiskToPartition";
var queryResults = new ManagementObjectSearcher(query);
var partitions = queryResults.Get();
foreach (var partition in partitions)
{
query = "ASSOCIATORS OF {Win32_DiskPartition.DeviceID='" + partition["DeviceID"] + "'} WHERE AssocClass = Win32_DiskDriveToDiskPartition";
queryResults = new ManagementObjectSearcher(query);
var drives = queryResults.Get();
foreach (var drive in drives)
{
deviceSerialNumber = drive["SerialNumber"].ToString();
}
}
if (!String.IsNullOrEmpty(deviceSerialNumber))
{
sbValues.AppendLine(deviceSerialNumber);
}
else
{
this.bMeasureHDDSerialNumber = false;
}
}
ASCIIEncoding asciEncoding = new ASCIIEncoding();
byte[] btAsciEncoded = asciEncoding.GetBytes(sbValues.ToString());
SHA256 sha = new SHA256CryptoServiceProvider();
btAsciEncoded = sha.ComputeHash(btAsciEncoded);
this.result = HexFormat.ByteArrayToString(btAsciEncoded);
}
return(this.result);
}
