Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!

• SSH key pairs – encrypt and authenticate remote connections
• PGP key pairs – encrypt e-mails, disks, arbitrary files to securely sign or delete them.
• SSL key pairs – encrypt TCP/IP communications and secure browser-server connections (used for SSL Certificates).

References

https://www.quora.com/What-is-the-difference-between-SSH-key-pairs-PGP-key-pairs-and-SSL-keys-What-is-the-intended-use-of-all-the-three-key-pairs

https://www.quora.com/What-is-the-difference-between-SSL-and-SSH-Are-they-both-just-a-way-to-safely-access-a-remote-computer-through-encryption-Do-they-also-transfer-data/answer/John-Mocan