3.4.6.1 Signature Creation for GSS_WrapEx()
Section 3.4.2 specifies the algorithm used by GSS_WrapEx() to create the signature. The signature contains the NTLMSSP_MESSAGE_SIGNATURE structure (section 2.2.2.9).
The checksum is computed over the concatenated input buffers using only the input data buffers where sign==TRUE for NTLMv1 and all of the input data buffers for NTLMv2, including the cleartext data buffers.