Support

CryptoPad encrypts short texts with public keys, on iPhone and on Android. It has no account and no server, so your keys and contacts are kept on your phone, not with us, and we cannot see or restore them.

Contact us: info@relcom.com. Please never send us private keys or decrypted messages; we never need them.

Quick start

1. Make a key. Open the Settings tab, type a name for the key and pick its type: on iPhone by tapping RSA, NIST or X25519 under the name, on Android with the arrow next to the button. Then tap the button, which reads Generate RSA Key, Generate NIST Key or Generate X25519 Key.
2. Share your public key. Tap Copy Public Key: on iPhone it is next to the key under Your Keys, on Android in the key's ⋮ menu. Paste it into any messenger or email. It is safe to share: it can only lock messages for you.
3. Add the people you write to. Copy their public key, open the Contacts tab, tap + on iPhone or Add Contact on Android, type a name, paste the key with Paste (iPhone) or Paste from Clipboard (Android), and tap Add.
4. Encrypt. Tap a contact to make it the recipient. On the Pad, type your text, tap Encrypt, then Copy Output, and paste the result into any chat.
5. Decrypt. Copy a message sent to you, tap Paste (iPhone) or Paste Input (Android) on the Pad, then Decrypt.

The same steps with screenshots of each app: Guides.

Common questions

I lost my key (or deleted the app). Can you recover it?

No. The private part of a key is made on your phone and only that phone can use it; nobody else, including us, can open a copy of it. If a key is deleted, messages encrypted for it cannot be opened any more. Make a new key and send your contacts its public part.

Do messages work between iPhone and Android?

Yes. Both apps use the same format: a message encrypted on one opens on the other, and a public key copied from one is accepted as a contact on the other.

Which key type should I choose?

All three work for encrypting and decrypting: RSA (RSA-4096), NIST (P-256) and X25519. X25519 and NIST keys are short and quick to make; RSA keys are longer and take a few seconds. On Android, X25519 keys can be made only on Android 13 or later (on older versions the option shows as “X25519 (Android 13+)” and cannot be chosen). If you or someone you write to uses an older Android phone, use RSA or NIST. You can have several keys.

I have a new phone. Do my keys move with it?

No — on either platform, plan to make new keys on the new phone and send your contacts the new public parts. Messages encrypted for your old keys can be opened only on the old phone, for as long as it still has them.

• iPhone: keys are stored as “this device only” and are never moved to a different iPhone, neither from a backup nor by a data transfer. Your contacts may come along with an iCloud or computer backup.
• Android: a backup or phone-to-phone transfer may copy the app's storage, but your keys in it are encrypted under a key that stays on the old phone, so CryptoPad on the new phone cannot use them. Your contacts may come along, depending on your backup settings.

Why does decryption fail?

CryptoPad tries every key you have. “Decryption failed: no matching key for this message” usually means one of these:

• the message was encrypted for a different key, for example an old key you deleted, or someone else's key;
• the text was cut or changed when copied, for example a missing character at the start or end, or a messenger split it into several messages;
• what you pasted is not a CryptoPad message. On Android this can also show as “Input must be base64-encoded”.

Ask the sender to check which of your public keys they used and to send the message again in one piece.

Why is the Encrypt button grey?

Pick a recipient first: open Contacts and tap a contact, so it shows a checkmark on iPhone or a filled circle on Android. Encrypt also needs some text on the Pad.

How do I delete a key or a contact?

On iPhone, swipe it to the left in Settings (keys) or Contacts (contacts), tap Delete and confirm. On Android, open the ⋮ menu next to it, tap Delete and confirm. What happens when you delete the whole app is in the privacy policy.

Is my data sent anywhere?

No. The app has no network access, no analytics and no account. See the privacy policy.

Reporting a problem

Write to info@relcom.com and tell us:

• your phone model and its iOS or Android version;
• the CryptoPad version: on iPhone in Settings › General › iPhone Storage › CryptoPad, on Android in Settings › Apps › CryptoPad;
• what you did, what you expected and what happened instead, with the exact text of any error;
• the key types involved, and whether the other person uses iPhone or Android.

A screenshot helps, as long as it shows no message you would not want us to read. Never send private keys or decrypted text. We do not need them, and the app never shows a private key anyway.

Reliable Communications s.r.o., Prokopova 2856/10, 130 00 Praha 3, Czech Republic.