What does the abbreviation CSP mean?

CSP is an acronym that means Cryptographic Service Provider, otherwise a software library-typically used in Microsoft Windows environments - with encoding and decoding functions that applications can use for strong authentication (to access on the software functionality) for e-mail security (encryption of electronic mail messages), Windows Logon, and for SSO in general (otherwise single sign-on, a system that allows independent authentication on systems and applicative  software ).
This feature is available by combining the use of a cryptographic smart card with a smart card reader, and to increase further the security, the authentication can be combined with a PIN request (personal identity number) or with a matching digital fingerprint.