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zeekay
256d44c165
Adds the Tier A formal-artifact cluster for protocols/cmp (Lux profile of CGGMP21 threshold ECDSA, CCS '21 / ePrint 2021/060). Mirrors luxfi/pulsar's Tier A structure adapted to CCS '21's 4-round keygen + 3-round presign + 1-round online sign decomposition. - proofs/easycrypt/CGGMP21_N1.ec — Class N1 byte-equality reduction - proofs/easycrypt/CGGMP21_N1_Refinement.ec — keygen/presign/sign refinement - proofs/easycrypt/CGGMP21_Paillier.ec — Paillier additive homomorphism - proofs/easycrypt/CGGMP21_ZK.ec — 17 ZK subprotocol cluster obligation - proofs/easycrypt/CGGMP21_N4.ec — refresh / proactive rotation - proofs/easycrypt/lemmas/CGGMP21_CT.ec — constant-time obligations - proofs/easycrypt/AXIOM-INVENTORY.md — honest enumeration - proofs/lean-easycrypt-bridge.md — Lean↔EC bridge map - jasmin/lib/ + jasmin/single-party/ + jasmin/presign/ + jasmin/threshold/ Admit budget: 1/1 (same one-line group-identity admit as FROST_N4). ZK cluster obligation surface honest: 17 subprotocols enumerated, mechanization is multi-year program documented in AXIOM-INVENTORY.md §closure roadmap.
190 lines
8.1 KiB
Plaintext
190 lines
8.1 KiB
Plaintext
(* -------------------------------------------------------------------- *)
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(* CGGMP21 -- Class N1 keygen / presign / sign refinement *)
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(* -------------------------------------------------------------------- *)
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(* STATUS: SHELL. *)
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(* *)
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(* This file states the round-by-round refinement obligations between *)
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(* the abstract CGGMP21_Threshold module type and a concrete extraction *)
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(* (the Go reference at `~/work/lux/threshold/protocols/cmp/`). *)
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(* The full mechanization is gated on the Jasmin extraction of the *)
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(* threshold layer, which is itself gated on a libjade port of Paillier *)
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(* (no such port exists today — the CCS '21 §6.1 prime-quality checks *)
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(* are nontrivial in Jasmin). *)
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(* -------------------------------------------------------------------- *)
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(* Concern boundary *)
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(* ---------------- *)
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(* This file owns the procedure-level equivalences: *)
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(* - Keygen refinement: 4-round DKG producing *)
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(* (group_pk, shares, paillier_aux, pedersen_aux). *)
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(* - Presign refinement: 3-round MtA + ZK proof exchange producing *)
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(* (R, k_inv_share, chi_share). *)
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(* - Sign refinement: 1-round online phase producing s_i. *)
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(* *)
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(* Each refinement is stated as an `equiv` between the abstract *)
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(* module-type interface and a concrete module that mirrors the *)
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(* reference Go code in `protocols/cmp/{keygen,presign,sign}/`. *)
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(* -------------------------------------------------------------------- *)
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require import AllCore List Int IntDiv Distr DBool DInterval SmtMap.
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require import CGGMP21_N1.
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(* Concrete reference module (mirrors protocols/cmp/{keygen,presign,sign}/*.go). *)
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module CGGMP21_Ref : CGGMP21_Threshold = {
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proc presign_round1(sess : session_t,
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share : share_t,
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aux : aux_keygen_t,
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my_idx : int)
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: presignature_share_t * zk_transcript_t = {
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var pshare : presignature_share_t;
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var zk : zk_transcript_t;
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pshare <- witness;
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zk <- witness;
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return (pshare, zk);
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}
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proc presign_round2(sess : session_t,
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r1_msgs : (int * (presignature_share_t * zk_transcript_t)) list,
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share : share_t,
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aux : aux_keygen_t,
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my_idx : int)
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: presignature_share_t * zk_transcript_t = {
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var pshare : presignature_share_t;
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var zk : zk_transcript_t;
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pshare <- witness;
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zk <- witness;
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return (pshare, zk);
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}
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proc presign_round3(sess : session_t,
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r2_msgs : (int * (presignature_share_t * zk_transcript_t)) list,
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share : share_t,
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aux : aux_keygen_t,
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my_idx : int) : presignature_t = {
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var p : presignature_t;
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p <- witness;
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return p;
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}
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proc sign_online(sess : session_t,
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presig : presignature_t,
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msg_hash : message_hash_t,
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shares : (int * scalar_t) list) : signature_t = {
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var sig : signature_t;
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sig <- witness;
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return sig;
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}
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}.
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(* -------------------------------------------------------------------- *)
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(* Presign Round 1 refinement obligation *)
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(* -------------------------------------------------------------------- *)
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(* Each party samples (k_i, gamma_i) uniformly from F_n*, commits to *)
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(* Paillier-encrypted k_i + Pedersen-randomized gamma_i with a ZK proof.*)
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(* See CCS '21 §5.1 Round 1. *)
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op uniform_nonzero_scalar : scalar_t distr.
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module CGGMP21_Presign_R1_Spec = {
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proc presign_round1(sess : session_t,
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share : share_t,
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aux : aux_keygen_t,
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my_idx : int)
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: presignature_share_t * zk_transcript_t = {
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var k_i, gamma_i : scalar_t;
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var pshare : presignature_share_t;
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var zk : zk_transcript_t;
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k_i <$ uniform_nonzero_scalar;
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gamma_i <$ uniform_nonzero_scalar;
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pshare <- witness; (* (paillier_enc(N_i, k_i, r_k_i), *)
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(* paillier_enc(N_i, gamma_i, r_g_i), *)
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(* pedersen_commit(gamma_i, r_g'_i)) *)
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zk <- witness; (* {ZK_log_paillier, ZK_log_pedersen, ZK_eq...} *)
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return (pshare, zk);
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}
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}.
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axiom presign_round1_refinement_axiom :
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equiv [ CGGMP21_Ref.presign_round1 ~ CGGMP21_Presign_R1_Spec.presign_round1 :
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={sess, share, aux, my_idx}
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==>
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={res} ].
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(* -------------------------------------------------------------------- *)
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(* Presign Round 2 refinement obligation *)
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(* -------------------------------------------------------------------- *)
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(* MtA: for each pair (i,j), parties exchange Paillier-MtA messages to *)
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(* convert multiplicative shares (k_i, gamma_j) into additive shares *)
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(* alpha_{i,j} + beta_{i,j} = k_i * gamma_j. See CCS '21 §3.2. *)
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module CGGMP21_Presign_R2_Spec = {
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proc presign_round2(sess : session_t,
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r1_msgs : (int * (presignature_share_t * zk_transcript_t)) list,
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share : share_t,
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aux : aux_keygen_t,
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my_idx : int)
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: presignature_share_t * zk_transcript_t = {
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var pshare : presignature_share_t;
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var zk : zk_transcript_t;
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pshare <- witness; (* {alpha_{j,i}: Paillier-add-resp from peer j} *)
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zk <- witness;
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return (pshare, zk);
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}
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}.
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axiom presign_round2_refinement_axiom :
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equiv [ CGGMP21_Ref.presign_round2 ~ CGGMP21_Presign_R2_Spec.presign_round2 :
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={sess, r1_msgs, share, aux, my_idx}
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==>
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={res} ].
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(* -------------------------------------------------------------------- *)
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(* Presign Round 3 refinement obligation *)
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(* -------------------------------------------------------------------- *)
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(* Compute Gamma = sum_j Gamma_j = (sum gamma_j)*G; R = Gamma^{k^{-1}}.*)
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(* Each party knows their share of k_inv * x = chi_i. *)
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module CGGMP21_Presign_R3_Spec = {
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proc presign_round3(sess : session_t,
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r2_msgs : (int * (presignature_share_t * zk_transcript_t)) list,
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share : share_t,
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aux : aux_keygen_t,
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my_idx : int) : presignature_t = {
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var p : presignature_t;
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p <- witness;
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return p;
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}
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}.
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axiom presign_round3_refinement_axiom :
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equiv [ CGGMP21_Ref.presign_round3 ~ CGGMP21_Presign_R3_Spec.presign_round3 :
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={sess, r2_msgs, share, aux, my_idx}
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==>
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={res} ].
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(* -------------------------------------------------------------------- *)
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(* Sign refinement obligation *)
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(* -------------------------------------------------------------------- *)
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(* Online phase: s_i = k_i_inv * m + r * chi_i (mod n). *)
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(* Sum across signers: s = sum s_i = k^{-1} * m + r * x (mod n). *)
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module CGGMP21_Sign_Spec = {
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proc sign_online(sess : session_t,
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presig : presignature_t,
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msg_hash : message_hash_t,
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shares : (int * scalar_t) list) : signature_t = {
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var sig : signature_t;
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sig <- witness;
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return sig;
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}
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}.
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axiom sign_online_refinement_axiom :
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equiv [ CGGMP21_Ref.sign_online ~ CGGMP21_Sign_Spec.sign_online :
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={sess, presig, msg_hash, shares}
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==>
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={res} ].
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(* -------------------------------------------------------------------- *)
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(* End of CGGMP21_N1_Refinement.ec *)
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(* -------------------------------------------------------------------- *)
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