Use of legacy providers

[harhan]

This code uses the legacy provider for requesting keys. While many MS CS services are configured to use this provider one should move to Microsoft Software Key Storage Provider (KSP) for all new deployments.

I suggest to add the KSP provider as default and add a "-legacy" switch.

https://www.pkisolutions.com/understanding-microsoft-crypto-providers/ - PKI Solutions have a nice overview of the various providers available.