/// <summary>
/// Computes and returns the 8-byte folded MD5 hash of the GUID.
/// </summary>
/// <param name="guid">The GUID.</param>
/// <returns>The 8-byte hash.</returns>
/// <remarks>
/// <para>
/// This works by:
/// </para>
/// <list type="number">
/// <item>Generating the 16-byte MD5 hash of the GUID.</item>
/// <item>Splitting the result in half to two 8-byte arrays.</item>
/// <item>XOR-ing the bytes of the two arrays to form a new 8-byte array.</item>
/// <item>Retuning the result.</item>
/// </list>
/// </remarks>
public static byte[] ToFoldedBytes(this Guid guid)
{
var md5Hash = CryptoHelper.ComputeMD5Bytes(guid.ToByteArray());
var result = new byte[8]; // $note(jefflill): I'm not actually splitting into two arrays.
for (int i = 0; i < 8; i++)
{
result[i] = (byte)(md5Hash[i] ^ md5Hash[i + 8]);
}
return(result);
}
/// <summary>
/// Computes and returns the 16-byte MD5 hash of the GUID.
/// </summary>
/// <param name="guid">The GUID.</param>
/// <returns>The 16-byte hash.</returns>
public static byte[] ToMd5Bytes(this Guid guid)
{
return(CryptoHelper.ComputeMD5Bytes(guid.ToByteArray()));
}