Loren Kohnfelder
More info
- Affiliation
- MIT, Microsoft, Google
- Known for
- The certificate concept (1978), STRIDE (1999)
Invented the certificate in a 1978 undergraduate thesis, then handed Microsoft STRIDE two decades later.
Diffie and Hellman had proposed a public directory of keys in 1976. Kohnfelder, then an MIT student, pointed out in his thesis Towards a Practical Public-key Cryptosystem that a central directory is both a bottleneck and a target, and that it is enough for a trusted party to sign the binding between a name and a key. He called that signed record a certificate. X.509 and the whole of modern PKI rest on the idea.
At Microsoft in 1999 he and Praerit Garg wrote the internal paper that introduced STRIDE, still the default starting point for threat modeling. He later wrote Designing Secure Software (2021). Two load-bearing pillars of the field, and hardly anyone outside it knows the name.