diff --git a/src/types/errors/DecryptionError.ts b/src/types/errors/DecryptionError.ts
index 58117ab..05ee071 100644
--- a/src/types/errors/DecryptionError.ts
+++ b/src/types/errors/DecryptionError.ts
@@ -7,7 +7,7 @@ export class DecryptionError extends Error {
     super()
 
     if (inputError.message.toLowerCase().includes('expected')) {
-      this.message = `The decryption key length or format is invalid`
+      this.message = `The decryption key length or format is invalid.`
     } else if (inputError.message.includes('The JWK "alg" member was inconsistent')) {
       this.message = `The decryption key is invalid.`
     } else {