Vlastimil Klíma

{{Short description|Czech cryptologist and computer security expert (born 1957)}}

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File:Vlastimil Klima (cropped).jpg

Vlastimil Klíma (born 19 February 1957 in Benešov) is a cryptographer,{{Cite news |last=Glanz |first=James |date=21 March 2021 |title=Cryptologists Discover Flaw In E-Mail Security Program |url=https://www.nytimes.com/2001/03/21/us/cryptologists-discover-flaw-in-e-mail-security-program.html |access-date=11 November 2024 |work=The New York Times|quote=Cryptologists Vlastimil Klima and Tomas Rosa find flaw in PGP, most widely used program for sending encrypted e-mail messages...}} computer security expert, and white hat hacker.{{Citation needed|date=November 2024}}

As an academic, he taught Applied Cryptography at the Faculty of Mathematics and Physics at Charles University in Prague. He is the author of several works in the field of cryptographic hash functions and digital signatures. Klíma received his doctorate from the Faculty of Mathematics and Physics at Charles University in 1984.

Klíma is the former Head of the research and development group at the Federal Ministry of Defense of the Czech Republic and the Czech National Security Authority.

Klíma authored the world's first on-the-fly encryption system, Windows 95 (98/NT/2000). As an ethical hacker, he successfully broke SSL protocol.

He currently works in the digital security sector.