Answers to common questions about iPGMail and PGP encryption.
PGP Basics
What is PGP?
PGP (Pretty Good Privacy) is an encryption system that lets you send private messages that only the intended recipient can read. It uses two keys:
- Public key — Share this freely. Others use it to encrypt messages to you.
- Private key — Keep this secret. You use it to decrypt messages sent to you.
Think of it like a mailbox: anyone can drop a letter in the slot (encrypt with your public key), but only you have the key to open it (your private key).
What’s the difference between PGP and OpenPGP?
OpenPGP is the open standard (defined in RFC 4880 and RFC 9580) based on the original PGP protocol. iPGMail implements OpenPGP, which means it’s compatible with:
- GPG (GNU Privacy Guard) on Mac, Windows, and Linux
- Mailvelope for webmail
- Other OpenPGP-compliant apps on any platform
In everyday conversation, “PGP” and “OpenPGP” are used interchangeably.
Where can I learn more about PGP?
For background reading, these Wikipedia articles are good starting points:
Compatibility
Does iPGMail work with Gmail, Outlook, or other email providers?
Yes. iPGMail works with any email provider—Gmail, Outlook, Yahoo Mail, iCloud, Fastmail, or your own mail server.
iPGMail encrypts your message before it’s sent. Your email provider only ever sees encrypted text, so it doesn’t matter which service you use.
Does iPGMail work with ProtonMail?
Yes, with some caveats.
ProtonMail uses its own internal encryption for messages between ProtonMail users. For standard PGP compatibility:
- The ProtonMail user needs to export their public key from ProtonMail settings
- They share that key with you (via email or other means)
- You import their key into iPGMail
- Now you can exchange encrypted messages using standard OpenPGP
ProtonMail’s PGP documentation →
Can I use iPGMail for business or HIPAA compliance?
Yes. iPGMail provides strong encryption suitable for:
- Business communications
- HIPAA-compliant healthcare messaging
- Legal and financial correspondence
- Journalist source protection
iPGMail supports RSA keys up to 4096-bit and modern elliptic curve cryptography (ECC), meeting or exceeding industry security standards.
Does iPGMail work on iPad?
Yes. iPGMail is a universal app that runs on both iPhone and iPad. If you enable iCloud sync, your keys are available on all your devices.
Does iPGMail work offline?
Yes. Encryption and decryption happen entirely on your device. You don’t need an internet connection to:
- Decrypt messages
- Encrypt new messages
- Manage your keys
You only need internet access to send emails, search keyservers, or sync with iCloud.
Security
How does iPGMail protect my private keys?
iPGMail uses multiple layers of protection:
| Passphrase encryption | Your private key is encrypted with your passphrase. Without it, the key is useless. |
| Encrypted database | Keys are stored in an encrypted database within the app. |
| iOS sandboxing | Other apps cannot access iPGMail’s data. |
| Device passcode | Your device’s lock screen protects all app data at rest. |
| Optional app PIN | Add a 4-digit PIN for extra protection within the app. |
| Face ID / Touch ID | Use biometrics instead of typing your passphrase each time. |
Are decrypted files secure on my device?
Decrypted files are stored in iPGMail’s sandboxed documents folder, protected by iOS security. Other apps cannot access them.
For maximum security with sensitive files:
- View decrypted content within iPGMail rather than exporting it
- Keep the encrypted original as your permanent copy
- Delete decrypted copies after viewing if the content is highly sensitive
What happens if I lose my device?
Your keys remain protected by multiple layers:
- Your device passcode prevents access to the phone
- Your app PIN (if enabled) prevents access to iPGMail
- Your passphrase protects each private key
If your device is lost or stolen:
- Use Find My iPhone to remotely wipe the device
- Your keys still exist wherever you originally exported them from (your computer)
- Re-import your keys to a new device
How do I backup my keys?
Your private keys should exist in at least two places:
- Your computer (where you originally created or imported them)
- iPGMail on your iOS device
For additional backup:
- Export your private key to an encrypted USB drive
- Store the USB drive in a secure physical location
- Never store unencrypted private keys in cloud storage
