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diff --git a/examples/redis-unstable/modules/vector-sets/mixer.h b/examples/redis-unstable/modules/vector-sets/mixer.h
new file mode 100644
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+++ b/examples/redis-unstable/modules/vector-sets/mixer.h
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+/* Redis implementation for vector sets. The data structure itself
+ * is implemented in hnsw.c.
+ *
+ * Copyright (c) 2009-Present, Redis Ltd.
+ * All rights reserved.
+ *
+ * Licensed under your choice of (a) the Redis Source Available License 2.0
+ * (RSALv2); or (b) the Server Side Public License v1 (SSPLv1); or (c) the
+ * GNU Affero General Public License v3 (AGPLv3).
+ * Originally authored by: Salvatore Sanfilippo.
+ *
+ * =============================================================================
+ *
+ * Mixing function for HNSW link integrity verification
+ * Designed to resist collision attacks when salts are unknown.
+ */
+
+#include <stdint.h>
+#include <string.h>
+
+static inline uint64_t ROTL64(uint64_t x, int r) {
+    return (x << r) | (x >> (64 - r));
+}
+
+// Use more rounds and stronger constants
+#define MIX_PRIME_1 0xFF51AFD7ED558CCDULL
+#define MIX_PRIME_2 0xC4CEB9FE1A85EC53ULL
+#define MIX_PRIME_3 0x9E3779B97F4A7C15ULL
+#define MIX_PRIME_4 0xBF58476D1CE4E5B9ULL
+#define MIX_PRIME_5 0x94D049BB133111EBULL
+#define MIX_PRIME_6 0x2B7E151628AED2A7ULL
+
+/* Mixer design goals:
+ * 1. Thorough mixing of the level parameter.
+ * 2. Enough rounds of mixing.
+ * 3. Cross-influence between h1 and h2.
+ * 4. Domain separation to prevent related-key attacks.
+ */
+void secure_pair_mixer_128(uint64_t salt0, uint64_t salt1,
+                          uint64_t id1_in, uint64_t id2_in, uint64_t level,
+                          uint64_t* out_h1, uint64_t* out_h2) {
+    // Order independence (A -> B links should hash as B -> A links).
+    uint64_t id_a = (id1_in < id2_in) ? id1_in : id2_in;
+    uint64_t id_b = (id1_in < id2_in) ? id2_in : id1_in;
+
+    // Domain separation: mix salts with a constant to prevent
+    // related-key attacks.
+    uint64_t h1 = salt0 ^ 0xDEADBEEFDEADBEEFULL;
+    uint64_t h2 = salt1 ^ 0xCAFEBABECAFEBABEULL;
+
+    // First, thoroughly mix the level into both accumulators
+    // This prevents predictable level values from being a weakness
+    uint64_t level_mix = level;
+    level_mix *= MIX_PRIME_5;
+    level_mix ^= level_mix >> 32;
+    level_mix *= MIX_PRIME_6;
+
+    h1 ^= level_mix;
+    h2 ^= ROTL64(level_mix, 31);
+
+    // Mix in id_a with strong diffusion.
+    h1 ^= id_a;
+    h1 *= MIX_PRIME_1;
+    h1 = ROTL64(h1, 23);
+    h1 *= MIX_PRIME_2;
+
+    // Mix in id_b.
+    h2 ^= id_b;
+    h2 *= MIX_PRIME_3;
+    h2 = ROTL64(h2, 29);
+    h2 *= MIX_PRIME_4;
+
+    // Three rounds of cross-mixing for better security.
+    for (int i = 0; i < 3; i++) {
+        // Cross-influence.
+        uint64_t tmp = h1;
+        h1 += h2;
+        h2 += tmp;
+
+        // Mix h1.
+        h1 ^= ROTL64(h1, 31);
+        h1 *= MIX_PRIME_1;
+        h1 ^= salt0;
+
+        // Mix h2.
+        h2 ^= ROTL64(h2, 37);
+        h2 *= MIX_PRIME_2;
+        h2 ^= salt1;
+    }
+
+    // Finalization with avalanche rounds.
+    h1 ^= h1 >> 33;
+    h1 *= MIX_PRIME_3;
+    h1 ^= h1 >> 29;
+    h1 *= MIX_PRIME_4;
+    h1 ^= h1 >> 32;
+
+    h2 ^= h2 >> 33;
+    h2 *= MIX_PRIME_5;
+    h2 ^= h2 >> 29;
+    h2 *= MIX_PRIME_6;
+    h2 ^= h2 >> 32;
+
+    *out_h1 = h1;
+    *out_h2 = h2;
+}