## External resources

### PGP: An email encryption software

Why and how to use openPGP ?

https://theprivacyguide.org/tutorials/pgp.html

### Signal

### Public-key cryptography (PKC)

Definition and explanation of Public-key Cryptography on Wikipedia

https://en.wikipedia.org/wiki/Public-key_cryptography

### Public key infrastructure

Definition of Public-key infrastructure on Wikipedia

https://en.wikipedia.org/wiki/Public_key_infrastructure

### Cryptography

Definition of Cryptography on Wikipedia

https://en.wikipedia.org/wiki/Cryptography

### History of cryptography

The history of Cryptography on Wikipedia

https://en.wikipedia.org/wiki/History_of_cryptography