Set this property with AH_MediumCtx_SetUser, get it with AH_MediumCtx_GetUser
Set this property with AH_MediumCtx_SetTokenContext, get it with AH_MediumCtx_GetTokenContext
Set this property with AH_MediumCtx_SetLocalSignKeySpec, get it with AH_MediumCtx_GetLocalSignKeySpec
Set this property with AH_MediumCtx_SetLocalCryptKeySpec, get it with AH_MediumCtx_GetLocalCryptKeySpec
Set this property with AH_MediumCtx_SetRemoteSignKeySpec, get it with AH_MediumCtx_GetRemoteSignKeySpec
Set this property with AH_MediumCtx_SetRemoteCryptKeySpec, get it with AH_MediumCtx_GetRemoteCryptKeySpec