| /* | |
| * qra.h — Discrete Agent Routing Automata (QRA) | |
| * | |
| * Routing alphabet (6 glyphs): | |
| * Π (PI, 0x01) - identity/continuation | |
| * Γ (GAMMA, 0x03) - intermediate state | |
| * Δ (DELTA, 0x04) - transition | |
| * Ω (OMEGA, 0x0A) - absorbing element (termination) | |
| * Λ (LAMBDA, 0xFF) - left identity | |
| * Ψ (PSI, 0x0B) - control element | |
| * | |
| * Routing tensor Q ∈ {0,...,5}^{6×6}: | |
| * Q[current_glyph][previous_glyph] = next_glyph | |
| * | |
| * Key properties: | |
| * - H(next | current, previous) = 0 nats (deterministic) | |
| * - Λ is left identity: Q[Λ][j] = j | |
| * - Ω is absorber: Q[Ω][j] = Ω | |
| * - Token lifetime via algebraic exhaustion (witness → absorption) | |
| */ | |
| extern "C" { | |
| typedef struct RoutingTensor RoutingTensor; | |
| typedef struct { | |
| int glyphs[3]; /* [w0, w1, w2]: current witness state */ | |
| } Witness; | |
| /** | |
| * hk_qra_step — Deterministic routing step | |
| * | |
| * @param current Current glyph | |
| * @param previous Previous glyph | |
| * @param rt Routing tensor | |
| * @return Next glyph | |
| */ | |
| int hk_qra_step(int current, int previous, RoutingTensor *rt); | |
| /** | |
| * hk_qra_evolve_witness — Evolve witness vector | |
| * | |
| * w' = [Q(w0, w1), Q(w1, w2), Q(w2, w0)] | |
| * | |
| * @param w Current witness | |
| * @param rt Routing tensor | |
| * @return Next witness | |
| */ | |
| Witness hk_qra_evolve_witness(Witness w, RoutingTensor *rt); | |
| /** | |
| * hk_qra_is_absorbed — Check if witness has reached absorber | |
| * | |
| * Returns 1 if all three glyphs are Ω (omega). | |
| * | |
| * @param w Witness | |
| * @return 1 if absorbed, 0 otherwise | |
| */ | |
| int hk_qra_is_absorbed(Witness w); | |
| /** | |
| * hk_qra_is_fixed — Check if witness is in fixed-point loop | |
| * | |
| * Returns 1 if all three glyphs are Λ (lambda, left identity). | |
| * Fixed points are INVALID for tokens (no replay resistance). | |
| * | |
| * @param w Witness | |
| * @return 1 if fixed point, 0 otherwise | |
| */ | |
| int hk_qra_is_fixed(Witness w); | |
| /** | |
| * hk_qra_token_lifetime — Compute steps to absorption | |
| * | |
| * Iteratively evolves witness until absorption (or max_steps reached). | |
| * Returns number of evolution steps. Rejects fixed points (returns -1). | |
| * | |
| * Token lifetime defines stateful replay resistance: | |
| * - Token issued with witness w_0 | |
| * - Each use evolves witness: w_i → w_{i+1} | |
| * - After T steps, w_T = [Ω, Ω, Ω] (absorbed, token invalid) | |
| * | |
| * @param initial Initial witness | |
| * @param rt Routing tensor | |
| * @param max_steps Maximum evolution iterations | |
| * @return Steps to absorption, or -1 if invalid/no absorption | |
| */ | |
| int hk_qra_token_lifetime(Witness initial, RoutingTensor *rt, int max_steps); | |
| /** | |
| * Debug output | |
| */ | |
| void hk_qra_print_tensor(RoutingTensor *rt); | |
| void hk_qra_print_witness(Witness w); | |
| } | |