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IDProjectCategoryView StatusLast Update
0011526GNUnettransport servicepublic2026-06-20 12:26
Reporterschanzen Assigned To 
PrioritynormalSeverityminorReproducibilityhave not tried
Status newResolutionopen 
Target Version1.0.0 
Summary0011526: PQ-secure TCP/UDP encryption
DescriptionWe must update our crypto.
In order to stay true to the steganographic noise requirement (Elligator) we could use a KEM combiner that uses a PQKEM which has ciphertexts that are indistinguishabled from noise.
The choices are:

ML-KEM (the compressed ciphertext is still kind of distinguishable)
NTRU-HRSS
FrodoKEM

FrodoKEM ciphertexts are much larger (10-15x), but it is more common.
PQclear implements both.
TagsNo tags attached.

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child of 0011527 assignedschanzen GNUnet PQ migration meta issue 

Activities

schanzen

2026-06-17 12:01

administrator   ~0028924

Probably sntrup is better than NTRU-HRSS

schanzen

2026-06-20 12:26

administrator   ~0028947

Actually we may also have the option of using https://www.ietf.org/archive/id/draft-veitch-kemeleon-00.html with ML-KEM.

ECC is pretty much set to X25519. So we need to decide on the combiner, and the PQ algorithm taking into accoutn KEM ciphertext size (we have a limitation on UDP datagram size).
The ML-KEM ciphertext is 1,088 bytes. Sntrup are slightly smaller.

Combiner options:
  - X-Wing
  - Chempat (https://www.ietf.org/archive/id/draft-josefsson-chempat-04.html)

PQ KEM:
  - sntrup
  - ML-KEM

libsodium already implements X-Wing with ML-KEM-768 and X25519. Both w/e Elligator and Kemeleon.
Still, it may be possible to retrofit this somehow.
Sntrup would have to be vendored (e.g. from OpenSSH, which ships a single C source file).
Implementing Chempat is trivial I believe, but only really necessary if we want a generic combiner.

Issue History

Date Modified Username Field Change
2026-06-17 11:41 schanzen New Issue
2026-06-17 11:43 schanzen Relationship added child of 0011527
2026-06-17 12:01 schanzen Note Added: 0028924
2026-06-20 12:26 schanzen Note Added: 0028947