Kraken offers an end-to-end email encryption option which provides an additional layer of security while communicating with us. Using this feature allows you to make sure that emails were actually sent by Kraken and that they weren’t intercepted or tampered with before you received them.
When the creator of PGP converted it into paid-license code, this resulted in an initiative to offer a free-license alternative which is called GNU Privacy Guard (GPG).
OpenPGP stands for Open-source PGP and became the IETF-approved standard for PGP communication which allows both PGP and GPG software to communicate with each other.
In other words, it doesn’t matter which of the two options you choose unless you are a developer, or make a moral decision to support free and open-source software. For ease of reading, we will use PGP from this point forward to describe both.