Windows7 注册表byte[]密钥解密

注册表位置：

\\HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion

值位置

DigitalProductId

从注册表中获取密钥的byte[]：

RegistryKey hklm = Registry.LocalMachine;
hklm = hklm.OpenSubKey("SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion");
byte[] digitalProductId = hklm.GetValue("DigitalProductId") as byte[];
textBox1.Text = DecodeProductKey(digitalProductId);

核心代码：

public static string DecodeProductKey(byte[] digitalProductId)
{
// Offset of first byte of encoded product key in
// 'DigitalProductIdxxx" REG_BINARY value. Offset = 34H.
const int keyStartIndex = 52;
// Offset of last byte of encoded product key in
// 'DigitalProductIdxxx" REG_BINARY value. Offset = 43H.
const int keyEndIndex = keyStartIndex + 15;
// Possible alpha-numeric characters in product key.
char[] digits = new char[]
{
'B', 'C', 'D', 'F', 'G', 'H', 'J', 'K', 'M', 'P', 'Q', 'R',
'T', 'V', 'W', 'X', 'Y', '2', '3', '4', '6', '7', '8', '9',
};
// Length of decoded product key
const int decodeLength = 29;
// Length of decoded product key in byte-form.
// Each byte represents 2 chars.
const int decodeStringLength = 15;
// Array of containing the decoded product key.
char[] decodedChars = new char[decodeLength];
// Extract byte 52 to 67 inclusive.
ArrayList hexPid = new ArrayList();
for (int i = keyStartIndex; i <= keyEndIndex; i++)
{
hexPid.Add(digitalProductId[i]);
}
for (int i = decodeLength - 1; i >= 0; i--)
{
// Every sixth char is a separator.
if ((i + 1) % 6 == 0)
{
decodedChars[i] = '-';
}
else
{
// Do the actual decoding.
int digitMapIndex = 0;
for (int j = decodeStringLength - 1; j >= 0; j--)
{
int byteValue = (digitMapIndex << 8) | (byte)hexPid[j];
hexPid[j] = (byte)(byteValue / 24);
digitMapIndex = byteValue % 24;
decodedChars[i] = digits[digitMapIndex];
}
}
}
return new string(decodedChars);
}