CAPICOM explained

CAPICOM should not be confused with Capcom.

CAPICOM is a discontinued ActiveX control created by Microsoft to help expose a select set of Microsoft Cryptographic Application Programming Interface (CryptoAPI) functions through Microsoft Component Object Model (COM). It was intended to enable every environment that supports ActiveX to use Microsoft Cryptographic technologies, including web pages that are opened with Microsoft Internet Explorer or any other web browser that supports ActiveX.^[1]

CAPICOM can be used to digitally sign data, inspect, verify and display their digital signature or digital certificate, add or remove certificates to or from the certificate stores, and finally, to encrypt or decrypt data.

CAPICOM Version 2.1.0.3, the latest and last version of CAPICOM, is officially supported on Windows Vista.^{[2] [3] [4]} However, Microsoft has announced that CAPICOM is discontinued and is no longer being developed. Microsoft suggests replacing CAPICOM with .NET Framework's X509 Cryptographic Classes and a number of other alternatives.^[5]

CAPICOM was not included in Windows 7. The linked Microsoft article goes into detail. ^[6]

Notes and References

1. Web site: Introducing CAPICOM . . Microsoft Corporation . March 2001 . 22 April 2011 . John . Lambert.
2. Web site: CAPICOM support on Windows Vista . . Microsoft Corporation . 19 October 2007 . 22 April 2011 . Magencio . Alejandro Campos.
3. Web site: CAPICOM Versions . Microsoft Developer Network . Microsoft Corporation . 19 April 2011 . 22 April 2011.
4. Web site: MS07-028: Vulnerability in CAPICOM could allow remote code execution . Microsoft Support Knowledge Base . Microsoft Corporation . 8 January 2017 . 18 January 2018.
5. Web site: Alternatives to CAPICOM (Windows) . Microsoft Developer Network . Microsoft Corporation . 19 April 2011 . 22 April 2011.
6. Web site: CAPICOM not in Windows 7 . Microsoft Developer Network . Microsoft Corporation . 18 January 2009 . 13 November 2014.