diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6166bcc..da22c93 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 - Secret keys are now restricted to 128 bits (16 bytes) or 256 bits (32 bytes)
+- The local part cannot contain the separator
 
 ## [0.2.0] - 2023-08-11
 
diff --git a/src/locales/en.json b/src/locales/en.json
index 9a5ba50..843a77d 100644
--- a/src/locales/en.json
+++ b/src/locales/en.json
@@ -43,6 +43,7 @@
 			"cameraNotReadable": "Camera not accessible (potentially already in use).",
 			"cameraOverconstrained": "Installed cameras are not suitable.",
 			"cameraStreamApiNotSupported": "Stream API is not supported in this browser.",
+			"localPartSeparator": "The local part cannot contain the separator.",
 			"unknown": "Unknown error."
 		}
 	},
diff --git a/src/locales/fr.json b/src/locales/fr.json
index db9cf68..90cdcd4 100644
--- a/src/locales/fr.json
+++ b/src/locales/fr.json
@@ -43,6 +43,7 @@
 			"cameraNotReadable": "Caméra inaccessible (potentiellement déjà utilisée).",
 			"cameraOverconstrained": "Les caméras détectées ne sont pas compatibles.",
 			"cameraStreamApiNotSupported": "L'API du flux de données vidéo n'est pas supportée par ce navigateur.",
+			"localPartSeparator": "La partie locale ne peut pas contenir le séparateur.",
 			"unknown": "Erreur inconnue."
 		}
 	},
diff --git a/src/views/AddAccountView.vue b/src/views/AddAccountView.vue
index da11f2b..6355aa6 100644
--- a/src/views/AddAccountView.vue
+++ b/src/views/AddAccountView.vue
@@ -47,6 +47,9 @@ const addAccount = () => {
 			if (separator.value.length != 1) {
 				throw new Error('addAccount.error.invalidSeparator');
 			}
+			if (localPart.value.includes(separator.value)) {
+				throw new Error('addAccount.error.localPartSeparator');
+			}
 			const key = base64Decode(privateKey.value);
 			if (!authorizedKeyLengths.includes(key.length)) {
 				throw new Error('addAccount.error.invalidKeyLength');