_hc_CryptProvider() returns a global handle to a Win32 Crypt Provider.
If the global handle is NULL, then a handle is allocated. Unfortunately,
due to a coding mistake the global handle variable, g_cryptprovider, was
never set and a new handle was allocated with each call.
Refactor the function to ensure that the global handle is the value
that is returned. Use NULL instead of 0 for pointer assignment.
Change-Id: If1ef3aa19cbd1d51860370db24c086e86922ff0d
Heimdal can be executed in environments in which the user
account profile is not loaded. In such environments it is
not possible to use PROV_RSA_FULL as it stores required
data within the profile. Instead, fallback to PROV_RNG which
does not store data within the profile and can be used to access
secure random number generator routines.
Change-Id: If600246f39645ed6bf5af0dd237f5adfddcf6c0c
