The document provides a guide on encrypting SMS messages using PGP for improved privacy, requiring an Android smartphone and the APG app. It outlines steps to set up the app, generate or import keys, and encrypt messages to contacts. Additionally, it emphasizes the importance of securely exchanging public keys and keeping passphrases safe.

1. Encrypting SMS with PGP
The reason for this?
Privacy.
What do we need?
●Android smartphone
●APG app (Android Privacy Guard application)
Why APG?
It handles every aspect of PGP encryption, providing a
simple to use interface and seamless integration with
other communication application as email, messaging
and file managers
July 2015, mail@angelparrales.com 1/8

2. Encrypting SMS with PGP
1) Adjust your device settings
so messages are not split every
160 characters, this is an SMS
inherent limitation easy to
override.
July 2015, mail@angelparrales.com 2/8

3. Encrypting SMS with PGP
2) Install APG
https://play.google.com/store/apps/details?id=org.thialfihar.android.apg
3) Create your key, or import if you have them already.
NEVER forget your
passphrase
Save and backup your
keys in a safe place
like USB
July 2015, mail@angelparrales.com 3/8

4. Encrypting SMS with PGP
4) Select a contact you already shared public keys
with. Go to “Encrypt to this contact”
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5. Encrypting SMS with PGP
5) Write the message. Tap “Share with...” and select
your default SMS application, provide your passphrase
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6. DEcrypting SMS with PGP
Copy the whole message text
● Open APG and select “Decrypt”, provide your
passphrase.
July 2015, mail@angelparrales.com 6/8

7. Encrypting SMS with PGP
Remarks:
● Public keys has to be previously exchanged with
your recipient by other means.
● Public keys can be exchanged by mail (unsafe),
downloaded from PGP servers given the key
fingerprint, or in person.
● Secret key is NEVER shared
● Passphrase has to be kept always safe
July 2015, mail@angelparrales.com 7/8

8. Encrypting SMS with PGP
RESOURCES:
Android Privacy Guard application
https://play.google.com/store/apps/details?id=org.thialfihar.android.apg
Android Privacy Guard (APG) project http://www.thialfihar.org/projects/apg/
OpenKeychain: Easy PGP application
https://play.google.com/store/apps/details?id=org.sufficientlysecure.keychain
The Enigmail Project, PC email clients plugin
https://www.enigmail.net/home/index.php
Phil Zimmermann, PGP creator https://www.philzimmermann.com
July 2015, mail@angelparrales.com 8/8