Blob
GUID MFSampleExtension_Encryption_KeyID = {0x76376591,0x795f,0x4da1,{0x86,0xed,0x9d,0x46,0xec,0xa1,0x09,0xa9} }
To get this attribute, call IMFAttributes::GetBlob.
To set this attribute, call IMFAttributes::SetBlob.
Header: Declared in mfapi.h.