Attachments: up to 10 files of 25 MB each
Add, remove and download attachments, how they are encrypted together with the message, and the limits — ten files per message, 25 MB each.
You can attach up to 10 files to one email, each up to 25 MB. Attachments travel inside the message: when the mail is encrypted, the files are encrypted with it, so our server stores and forwards them without being able to open them.
Attach files
- In the composer, click the paperclip (Attach file). A file picker opens; you can select several files at once.
1Attach file2Attached file: name and size3RemoveWeb & desktop 
1231Attach file2Attached file: name and size3RemoveiPhone 1231Attach file2Attached file: name and size3RemoveAndroid - Each file appears as a chip above the toolbar with its name and size. Click ✕ on a chip to remove it.
- With more than one file, a header reads N Files and the total size; the chevron next to it collapses or expands the list.
13 Files and total size2Collapse the list3One attachment: name and size4RemoveWeb & desktop 
123413 Files and total size2Collapse the list3Size — of the 25 MB limit4RemoveiPhone 123413 Files and total size2Collapse the list3Size — of the 25 MB limit4RemoveAndroid - Write the rest of your message and click Send.
You can also drag files from your desktop onto the composer. A Drop files here overlay appears while you hover. Dropped files are added as attachments; images dropped this way are attached as files, not placed in the text — use Add inline image for that (Formatting and inline images).
Tap the paperclip in the composer's top bar. The system file picker opens (Files on iPhone, the document picker on Android). Attachments are shown as cards with a file icon, the name and the size as … of 25 MB; tap ✕ on a card to remove it. To put a photo into the text rather than attach it, open the ⋮ menu and choose Add inline image, which opens your photo library. The first time, the app asks for photo access.
Limits and the messages you may see
| Limit | What happens |
|---|---|
| More than 10 files | The paperclip is disabled once 10 are attached. Selecting more than fit shows You can attach up to 10 files. Only the first … you selected were added. |
| A file over 25 MB | That file is skipped with File … exceeds size limit of 25 MB.; the others are still added. |
| Total draft too large | Drafts are stored encrypted; if the encrypted draft with everything in it would exceed the server's draft size limit (400 MB), saving fails with Total size exceeds 400 mb. |
The 25 MB limit is per file and is the same for images placed inline in the text. Accepted types include images, video, audio, PDF, plain text, CSV, JSON, Word and Excel files, Apple Pages/Numbers/Keynote files, and .asc PGP key files. Anything the picker lets you choose is attached with a generic type.
Attachments are base64-encoded inside the message (about a third larger than the file), then encrypted and stored as text. For larger files use a file-sharing service and send the link by email.
How attachments are encrypted
Files never leave your device in the clear when the mail is encrypted. The composer builds one MIME message — body, inline images and attachments — and then:
- To a Private.Ki recipient: the whole message, files included, is PGP-encrypted to that recipient's public key. One copy per recipient, each encrypted separately.
- To an outside address with Encrypt on: the whole message is PGP-encrypted to the recipient keys you hold (PGP/MIME,
encrypted.asc), so a standard OpenPGP mail client can open the files. - To an outside address with Encrypt off: the message and its files leave as ordinary email.
- While it is still a draft: everything is AES-encrypted on your device before it is saved — see Drafts.
Details of what is encrypted where: What is encrypted where.
Download attachments you receive
Open the message. Under the text, Attached files: N lists each file with its name and size; on a message that was encrypted the size is followed by decrypted, meaning the file was opened on your device.
12341234- Click the download icon on a file to save that file.
- Click the download icon next to Attached files (Download attached files) to save all of them as one
attachments.zip. - Images placed inline in the text can be saved together with Download inline attachments.
Tapping a download icon opens the system share sheet titled Save
What our server sees
Cannot see
- The contents of attachments in an encrypted message, including their file names and types — they are inside the encrypted body
Can see
- The size of the encrypted message as a whole
- Attachments of an outside message sent with Encrypt off — that is plain email
Common questions
Can I attach a folder?
No. Select the files inside it, or zip the folder first (the zip counts as one file and must be under 25 MB).
The paperclip is greyed out.
You already have 10 files attached. Remove one to add another.