How Zeek Can Help With Post-Quantum Cryptography

Hi,

I’m a cryptography enthusiast, so I’m interested in the impact of PQC (Post-Quantum Cryptography). Naturally, I wondered what Zeek could contribute in this regard. Quite simply, it can help identify the protocols a company’s servers are using in order to target those that aren’t yet using protocols considered secure against this threat (more on this soonly). It would be surprising if someone hadn’t already had this idea, and precisely. A quick Google search led me to github, which does exactly that.

Here is the “pqc.log” file

#separator \x09
#set_separator  ,
#empty_field    (empty)
#unset_field    -
#path   pqc
#open   2026-09-22-11-01-05
#fields uid     host    is_client       is_hybrid       service pqc_algs
#types  string  addr    bool    bool    string  vector[string]
Cu2Bqp1FpldVSUwNHe      162.212.157.188 T       T       ssh     mlkem768x25519-sha256,sntrup761x25519-sha512,sntrup761x25519-sha512@openssh.com
CoKuZmm3tQvNN33s5       162.212.157.188 T       T       ssl     X25519MLKEM768
CoKuZmm3tQvNN33s5       8.8.8.8 F       T       ssl     X25519MLKEM768
CMFAcJ1AHkURD4hISh      162.212.157.188 T       T       ssl     X25519MLKEM768
CMFAcJ1AHkURD4hISh      8.8.4.4 F       T       ssl     X25519MLKEM768
aGYwInglsyPm2OWi        2.57.122.53     T       T       ssh     mlkem768x25519-sha256
C0lVlltX7eMBCVpQk       162.212.157.188 F       T       ssh     mlkem768x25519-sha256,sntrup761x25519-sha512@openssh.com
C0lVlltX7eMBCVpQk       93.123.109.192  T       T       ssh     mlkem768x25519-sha256

It is then easy to sort out who uses what. A great example of the tool’s contribution.

Cheers.