Re: Trying to relate PKCS & IETF standards to encoding rules

[Stephen Kent <kent@xxxxxxx>]

Walter,

The ITU-T X.509 and the IETF PKIX specs call for binary encoding of 
the ASN.1 for certs and CRLs, specifically DER, as you noted.

PEM, which is now historical, also called for binary encoding  (DER) 
of the ASN.1, and then specified the base64 encoding of the binary 
representation for "safe" carriage over SMTP.

So the two sets of specs were not in conflict. It's just that PEM 
specified an additional layer of encoding for content transfer 
purposes, which is what MIME does as well, when necessary.

DER to base64 is an easy encoding, because base64 takes any binary 
sytring and says how to encode it as text.

Steve