diff --git a/EnvelopeGenerator.API/Controllers/CacheController.cs b/EnvelopeGenerator.API/Controllers/CacheController.cs
index 8b15dc46..8379d4eb 100644
--- a/EnvelopeGenerator.API/Controllers/CacheController.cs
+++ b/EnvelopeGenerator.API/Controllers/CacheController.cs
@@ -31,7 +31,7 @@ public class CacheController(
         [FromBody] SignatureCacheRequest request,
         CancellationToken cancel)
     {
-        var cacheKey = $"{SignatureCacheKeyPrefix}{User.ReceiverSignature}";
+        var cacheKey = $"{SignatureCacheKeyPrefix}{User.ReceiverSignature()}";
         var json = JsonSerializer.Serialize(request);
         
         var options = cacheOptions.Value.SignatureCacheExpiration.HasValue
@@ -50,7 +50,7 @@ public class CacheController(
     [HttpGet("SignatureCapture/{envelopeKey}")]
     public async Task<IActionResult> GetSignature([FromRoute] string envelopeKey, CancellationToken cancel)
     {
-        var cacheKey = $"{SignatureCacheKeyPrefix}{User.ReceiverSignature}";
+        var cacheKey = $"{SignatureCacheKeyPrefix}{User.ReceiverSignature()}";
         var json = await cache.GetStringAsync(cacheKey, cancel);
 
         if (json is null)
@@ -67,7 +67,7 @@ public class CacheController(
     [HttpDelete("SignatureCapture/{envelopeKey}")]
     public async Task<IActionResult> DeleteSignature([FromRoute] string envelopeKey, CancellationToken cancel)
     {
-        var cacheKey = $"{SignatureCacheKeyPrefix}{User.ReceiverSignature}";
+        var cacheKey = $"{SignatureCacheKeyPrefix}{User.ReceiverSignature()}";
         await cache.RemoveAsync(cacheKey, cancel);
 
         return Ok();