From 317eabc4eb6052d8447f0ce6a61a1c39b00671dc Mon Sep 17 00:00:00 2001
From: Ginger <ginger@gingershaped.computer>
Date: Fri, 23 Jan 2026 14:18:19 -0500
Subject: [PATCH] feat: Add arbit utility module

---
 Cargo.lock              |  7 +++++++
 Cargo.toml              |  4 ++++
 src/core/Cargo.toml     |  1 +
 src/core/utils/arbit.rs | 13 +++++++++++++
 src/core/utils/mod.rs   |  1 +
 5 files changed, 26 insertions(+)
 create mode 100644 src/core/utils/arbit.rs

diff --git a/Cargo.lock b/Cargo.lock
index 34847a6f2..62dc11413 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1123,6 +1123,7 @@ dependencies = [
  "ctor",
  "cyborgtime",
  "either",
+ "fastrand",
  "figment",
  "futures",
  "hardened_malloc-rs",
@@ -1921,6 +1922,12 @@ dependencies = [
  "zune-inflate",
 ]
 
+[[package]]
+name = "fastrand"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37909eebbb50d72f9059c3b6d82c0463f2ff062c9e95845c43a6c9c0355411be"
+
 [[package]]
 name = "fax"
 version = "0.2.6"
diff --git a/Cargo.toml b/Cargo.toml
index 30e110948..fc4143d42 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -70,6 +70,10 @@ version = "0.1.3"
 [workspace.dependencies.rand]
 version = "0.8.5"
 
+# used for stamps
+[workspace.dependencies.fastrand]
+version = "2.3.0"
+
 # Used for the http request / response body type for Ruma endpoints used with reqwest
 [workspace.dependencies.bytes]
 version = "1.10.1"
diff --git a/src/core/Cargo.toml b/src/core/Cargo.toml
index 8139f2d3e..4c75f5af2 100644
--- a/src/core/Cargo.toml
+++ b/src/core/Cargo.toml
@@ -71,6 +71,7 @@ core_affinity.workspace = true
 ctor.workspace = true
 cyborgtime.workspace = true
 either.workspace = true
+fastrand.workspace = true
 figment.workspace = true
 futures.workspace = true
 http-body-util.workspace = true
diff --git a/src/core/utils/arbit.rs b/src/core/utils/arbit.rs
new file mode 100644
index 000000000..36ef28c63
--- /dev/null
+++ b/src/core/utils/arbit.rs
@@ -0,0 +1,13 @@
+pub const ARBIT_LENGTH: usize = 32;
+/// An arbit is an opaque, random 32-byte identifier.
+/// They are useful as unique, unordered database keys with no particular
+/// semantics except uniqueness.
+pub type Arbit = [u8; ARBIT_LENGTH];
+
+#[must_use]
+#[inline]
+pub fn arbit() -> Arbit {
+	let mut arbit = [0; ARBIT_LENGTH];
+	fastrand::fill(&mut arbit);
+	arbit
+}
diff --git a/src/core/utils/mod.rs b/src/core/utils/mod.rs
index be7ccb19a..377347d1b 100644
--- a/src/core/utils/mod.rs
+++ b/src/core/utils/mod.rs
@@ -1,3 +1,4 @@
+pub mod arbit;
 pub mod arrayvec;
 pub mod bool;
 pub mod bytes;