You could have invented PEM encoding

I saw the phrase "Certificate only, PEM encoded" in an e-mail about an SSL certificate and assumed PEM must be some complicated cryptography standard. No. It's literally two lines of ASCII wrapping a base64 literal: -----BEGIN {something}-----, followed by an arbitrary number of base64 literal lines, followed by -----END {something}-----. It stands for Privacy-Enhanced Mail.

This seems similar to the OpenSSH private key format, which looks like (for example):

-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: AES-128-CBC,8BB746DE158D4DDFCFD723C901F093D6

... base64 ...
-----END RSA PRIVATE KEY-----

The OpenSSH private key format seems slightly more complicated in that it has these metadata fields that look sort of like HTTP headers. But it's still pretty simple.