PGP with stock Android Email Client

Without getting into the innards of what PGP is and who it is for, I will assume that you are here because you straight away want to know how you can use PGP on your android device.

My setup is here, and I hope this works across most android devices, but just in case:

1. Android 4.3
2. Samsung Galaxy Note 3 SM-N900
3. Built-in e-mail client.
4. Assumption: You already have a key pair you wish to import and use.

(If you want to use a separate e-mail client, I highly recomend K-9 mail, which works very beautifully with APG, all available free in the Play Store).

1. Transfer your key pair from wherever you store them, to your device. There are many ways to do this, but i use Dropbox. 
2. On the device, save the key par to /openpgp/export/ on the built in storage. You can export directly from Dropbox to any location on your device.
3. Rename the keys to the following format:

     __0x_Pri.asc

     __0x_Pub.asc 

For the private and public keys respectively. For example, if your email configuration is as follows:

E-Mail address: john@xxxxxxx.net
Name: John XXXXNET
Key ID: 0xABCD1234

Your file names would be:

 john@xxxxxxx.net_John XXXXNET_0xABCD1234_Pri.asc
 john@xxxxxxx.net_John XXXXNET_0xABCD1234_Pub.asc

4. On your device, import the key-pair as follows: Settings - your_email_account - More Settings - Security Options - Private (or Public Keys); then click "Import Keys" on the menu option.
Hope this helps.