diff --git a/lib/api/consumers/format-to-legacy-helpers.js b/lib/api/consumers/format-to-legacy-helpers.js
index 9ce41039..45ca8c4e 100644
--- a/lib/api/consumers/format-to-legacy-helpers.js
+++ b/lib/api/consumers/format-to-legacy-helpers.js
@@ -113,7 +113,7 @@ export const formatCommonToponymDataForLegacy = (commonToponym, district, pseudo
     legacyCommonToponymId = `${cog}_${pseudoCodeVoieGenerator.getCode(legacyLabelValue, codeAncienneCommune)}`.toLowerCase()
     // If the pseudo code is already used, we generate a new one with a hash from the common toponym id
     if (commonToponymLegacyIDSet.has(legacyCommonToponymId)) {
-      legacyCommonToponymId = `${cog}_${createHmac('sha256').update(id).digest('hex').slice(0, 5)}`
+      legacyCommonToponymId = `${cog}_${createHmac('sha256', 'ban').update(id).digest('hex').slice(0, 5)}`
     }
   }