docs: clarify X3DH primitive interfaces and passive-secrecy game#3
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jinxinglim wants to merge 4 commits intomainfrom
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docs: clarify X3DH primitive interfaces and passive-secrecy game#3jinxinglim wants to merge 4 commits intomainfrom
jinxinglim wants to merge 4 commits intomainfrom
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Document current scope (deterministic, no keygen) and what extensions are needed for security proofs (probabilistic encaps, keygen). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Document current scope (deterministic, no nonce) and what extensions are needed for security proofs (nonce parameter, probabilistic encrypt). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Document the lowercase/uppercase private/public key convention and replace ASCII SK_B with SKᵦ for consistency with SKₐ. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
- Expand the game description to list the 5 specific private keys (ikₐ, ekₐ, ikᵦ, spkᵦ, opkᵦ) and note that the random key is sampled from SK (the KDF's output space) - Explain why T is embedded at DH3 specifically: it's the only DH value whose computation needs both secret scalars hidden in the DDH challenge (ekₐ, spkᵦ); the other DH values each involve at least one scalar the reduction samples itself Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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@jinxinglim could you please answer my comment?
| embeds T as DH3, queries the ROM on the resulting DH tuple to | ||
| get a session key, and passes it directly to the adversary. | ||
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| Why DH3? Among the four X3DH DH values, DH3 = ekₐ • SPKᵦ is the |
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Could you revise and elaborate this further?
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Summary
Documentation-only refinements made while reading through the X3DH-related files. Adds future-work notes to the primitive interfaces (KEM, AEAD), documents a notation convention in X3DH.lean, and expands explanations in the passive-secrecy game file.
No code/theorem changes — only comments, doc headers, and one cosmetic subscript fix.
Files changed
PQXDHLean/KEM.leanencaps/decaps, nokeygen(sufficient for correctness proofs)encapsand akeygenoperation, plus a suggested refactor pattern (separateKEMSpecalongsideKEM, mirroring theKDF/KDFOraclesplit)PQXDHLean/AEAD.leanencryptfor IND-CPASecurityDefs.leanPQXDHLean/X3DH/X3DH.leanF), uppercase names denote public keys (group elements inG), subscriptsₐ/ᵦindicate owner (Alice / Bob)SK_B→SKᵦ(matches existingSKₐ)PQXDHLean/X3DH/X3DHPassiveMessageSecrecy.leanSK(the KDF's output space)Tis embedded at DH3 specifically: DH3 =ekₐ • SPKᵦis the only DH value whose computation needs both secret scalars hidden in the DDH challenge; DH1/DH2/DH4 each involve at least one scalar the reduction samples itself