diff --git a/src/main.rs b/src/main.rs
index ce66e97..f6c1411 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -126,7 +126,12 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         println!("Contact URI: {}", contact_uri);
 
         let token = match args.token {
-            Some(token) => token,
+            Some(token) => {
+                if token.as_bytes().len() >= MAX_BYTES_PER_TRANSACTION {
+                    return Err("Token is too long".into())
+                }
+                token
+            },
             None => {
                 Uuid::new_v4().to_string()
             }
@@ -185,7 +190,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 
         // create file with token
         let token_accessrights = generate_file_access_rights(FileAccessRights::FREE as u8, 0x00, 0x00, 0x00)?;
-        desfire.create_file_standard(0x03, FileCommunication::PLAIN, token_accessrights, token.as_bytes().len() as u32)?;
+        desfire.create_file_standard(0x03, FileCommunication::PLAIN, token_accessrights, MAX_BYTES_PER_TRANSACTION as u32)?; // Max
         desfire.write_data(0x03, 0x00, token.as_bytes())?;
         println!("created token file");