S/MIME Preferences

1.	Go to Options->S/MIME

2.	Choose your preferred S/MIME engine

internal implementation and Microsoft CryptoAPI are offered

Depending on your choice the settings vary.

The main difference between the two engines is that The Bat!'s does not use any outside code. Thus the internal implementation will run on older Windows systems (like Win9x or NT 3.51). The disadvantage is a lack of flexibility: when it comes to using different third-party algorithms, storage media, or devices that perform certain operations at a hardware level, you will need to use the CryptoAPI engine, but it may work differently or with some limitations under different versions of Microsoft Windows.