There are two styles of public key, both with Base64 between the boundaries:
-----BEGIN RSA PUBLIC KEY-----
-----END RSA PUBLIC KEY-----
and
-----BEGIN PUBLIC KEY-----
-----END PUBLIC KEY-----
The top answer gives a stellar explanation of internals in response to OP asking how to convert between them.
For the former (older) format, there is this overview in the middle of the post:
> [This is an] PEM DER ASN.1 PKCS#1 RSA Public key
> - PEM: synonym for base64
> - DER: a flavor of ASN.1 encoding
> - ASN.1: the binary encoding scheme used
> - PKCS#1: The formal specification that dictates representing a public key as structure that consists of modulus followed by an exponent
> - RSA public key: the public key algorithm being used
Trivial!
I really appreciated the explanation of all these terms in one place, even if I question that PEM really just means Base64 it is likely a useful simplification.
