diff --git a/backend/deps.edn b/backend/deps.edn
index 650c8a479..a1c4feac5 100644
--- a/backend/deps.edn
+++ b/backend/deps.edn
@@ -30,6 +30,7 @@
   com.zaxxer/HikariCP {:mvn/version "5.0.1"}
 
   funcool/datoteka {:mvn/version "3.0.64"}
+  io.whitfin/siphash {:mvn/version "2.0.0"}
 
   buddy/buddy-hashers {:mvn/version "1.8.158"}
   buddy/buddy-sign {:mvn/version "3.4.333"}
diff --git a/backend/src/app/db.clj b/backend/src/app/db.clj
index 8785f272e..85dad9b7f 100644
--- a/backend/src/app/db.clj
+++ b/backend/src/app/db.clj
@@ -27,6 +27,8 @@
    com.zaxxer.hikari.HikariConfig
    com.zaxxer.hikari.HikariDataSource
    com.zaxxer.hikari.metrics.prometheus.PrometheusMetricsTrackerFactory
+   io.whitfin.siphash.SipHasher
+   io.whitfin.siphash.SipHasherContainer
    java.io.InputStream
    java.io.OutputStream
    java.lang.AutoCloseable
@@ -431,10 +433,19 @@
 
 ;; --- Locks
 
+(def ^:private siphash-state
+  (SipHasher/container
+   (uuid/get-bytes uuid/zero)))
+
+(defn uuid->hash-code
+  [o]
+  (.hash ^SipHasherContainer siphash-state
+         ^bytes (uuid/get-bytes o)))
+
 (defn- xact-check-param
   [n]
   (cond
-    (uuid? n) (uuid/get-word-high n)
+    (uuid? n) (uuid->hash-code n)
     (int? n)  n
     :else (throw (IllegalArgumentException. "uuid or number allowed"))))
 
diff --git a/common/src/app/common/uuid.cljc b/common/src/app/common/uuid.cljc
index 1a71256ef..011a50b6e 100644
--- a/common/src/app/common/uuid.cljc
+++ b/common/src/app/common/uuid.cljc
@@ -12,7 +12,9 @@
    #?(:clj [clojure.core :as c])
    #?(:cljs [app.common.uuid-impl :as impl])
    #?(:cljs [cljs.core :as c]))
-  #?(:clj (:import java.util.UUID)))
+  #?(:clj (:import
+           java.util.UUID
+           java.nio.ByteBuffer)))
 
 (def zero #uuid "00000000-0000-0000-0000-000000000000")
 
@@ -51,3 +53,11 @@
 
 #?(:clj
    (dm/export impl/get-word-low))
+
+#?(:clj
+   (defn get-bytes
+     [^UUID o]
+     (let [buf (ByteBuffer/allocate 16)]
+       (.putLong buf (.getMostSignificantBits o))
+       (.putLong buf (.getLeastSignificantBits o))
+       (.array buf))))