diff --git a/src/commons/util/ext_serde.rs b/src/commons/util/ext_serde.rs
index 623fff77..7891eb8e 100644
--- a/src/commons/util/ext_serde.rs
+++ b/src/commons/util/ext_serde.rs
@@ -1,5 +1,5 @@
 //! Defines helper methods for Serializing and Deserializing external types.
-use std::str::FromStr;
+use std::{str::FromStr, sync::atomic::{AtomicU64, Ordering}};
 
 use bytes::Bytes;
 use log::LevelFilter;
@@ -162,3 +162,22 @@ where
     let string = String::deserialize(d)?;
     Facility::from_str(&string).map_err(|_| de::Error::custom(format!("Unsupported syslog_facility: \"{}\"", string)))
 }
+
+//------------- AtomicU64 -----------------------------------------------------
+// Implemented automatically by Serde derive but only for x86_64 architectures,
+// for other architectures (such as armv7 for the Raspberry Pi 4b) it has to be
+// implemented manually.
+
+pub fn de_atomicu64<'de, D>(d: D) -> Result<AtomicU64, D::Error>
+where
+    D: Deserializer<'de>,
+{
+    Ok(AtomicU64::new(u64::deserialize(d)?))
+}
+
+pub fn ser_atomicu64<S>(v: &AtomicU64, s: S) -> Result<S::Ok, S::Error>
+where
+    S: Serializer,
+{
+    s.serialize_u64(v.load(Ordering::SeqCst))
+}
\ No newline at end of file
diff --git a/src/daemon/auth/common/crypt.rs b/src/daemon/auth/common/crypt.rs
index 4d18f3ee..0bb5be36 100644
--- a/src/daemon/auth/common/crypt.rs
+++ b/src/daemon/auth/common/crypt.rs
@@ -27,6 +27,7 @@ use std::{
 use crate::commons::{
     error::{Error, KrillIoError},
     KrillResult,
+    util::ext_serde,
 };
 
 const CHACHA20_KEY_BIT_LEN: usize = 256;
@@ -41,6 +42,11 @@ const UNUSED_AAD: [u8; 0] = [0; 0];
 #[derive(Debug, Deserialize, Serialize)]
 pub struct NonceState {
     sender_unique: [u8; 4], //   32 bits
+
+    #[serde(
+        deserialize_with = "ext_serde::de_atomicu64",
+        serialize_with = "ext_serde::ser_atomicu64"
+    )]
     counter: AtomicU64,     // + 64 bits = 96 bits = CHACHA20_NONCE_BIT_LEN
 }