D-Trust signature and seal cards on your phone
CodeB Wallet signs PDFs with D-Trust cards that have an NFC interface – straight from your Android phone, without a card reader. Fully tested with real cards: qualified signatures and qualified seals with the D-Trust NFC signature and seal cards. CodeB Wallet itself is not certified.
Which D-Trust cards work
D-Trust Card 5.1 – signature card for a person: qualified electronic signature.
D-Trust Card 5.4 – seal card for an organisation: qualified electronic seal.
Both in the Standard (RSA) and Multi (ECC) variants. D-Trust cards of generation 4 have no contactless interface; the app recognises them and tells you that they need a card reader on a computer.
How to sign a PDF with a D-Trust card
- On the home screen tap Sign, then Select document and pick a PDF on your phone.
- Check the document, then tap Sign with signature card.
- Enter the 6-digit card access number (CAN) printed on the card. The app offers the last number that worked.
- Hold the card flat against the back of your phone and leave it there until signing is finished.
- Enter your PIN. The card signs the document, and the app adds a trusted timestamp.
- You see “Document signed”, with the card used and whether its certificate states a qualified electronic signature. Tap Save to phone or Share.
CodeB Wallet never uses the last PIN try. If the card says only one try is left, nothing is sent – use your card issuer’s own software or service, so that a typing error elsewhere cannot block your card.
Qualified signatures and seals
The card creates the signature or seal with the key on its chip – the key never leaves the card. CodeB Wallet reads the card’s certificate and shows whether it is qualified.
Signatures and seals are embedded in the PDF as PAdES (ETSI EN 319 142) with a trusted timestamp. Fully tested with real cards: qualified signatures and qualified seals with the D-Trust NFC signature and seal cards. CodeB Wallet itself is not certified.
PIN and transport PIN
A new D-Trust card comes with a transport PIN. Set your own PIN first with your card issuer’s tools; CodeB Wallet tells you if the card still has its transport PIN and sends nothing.
CodeB Wallet never uses the last PIN try, and a wrong PIN is never retried automatically.
Tips for a stable connection
Hold the card flat against the back of the phone and keep it still until signing is finished. Remove thick phone cases.
On Android 14 and later the app shows where your phone’s NFC antenna is. If the connection drops, the app continues by itself as soon as the card is back – the card access number is not asked again.
Questions about D-Trust cards
Can I sign with my D-Trust card on an Android phone?
Yes, with the D-Trust Card 5.1 and 5.4, which have an NFC interface. Enter the card access number (CAN), hold the card to the phone and enter your PIN – the card signs the PDF. Fully tested with real cards; CodeB Wallet is currently being tested in closed groups.
Can an organisation seal PDFs with the D-Trust seal card?
Yes. With the D-Trust Card 5.4 an organisation applies its qualified electronic seal to PDFs from a phone. Fully tested with real cards: qualified seals with the D-Trust NFC seal card. CodeB Wallet itself is not certified.
My D-Trust card is not recognised – why?
D-Trust cards of generation 4 have no contactless interface and need a card reader on a computer. If a generation 5 card is not found, check the card access number and hold the card still at the phone’s NFC antenna.
Do I need an account or a browser plug-in?
No. The app talks to the card directly over NFC. The PDF stays on your phone; only a fingerprint (hash) of the signature is sent to the CodeB timestamp service for the trusted timestamp.
What about my PIN?
The app shows the remaining tries and never uses the last one. Change a transport PIN or unblock a PIN with your card issuer’s tools.
Install the test version (Google Play) Closed beta: works only for invited testers who are signed in to Google Play with the e-mail address we have on our tester list.