How to determine RSA block size for decryption A message coded with RSA is broken up into blocks, then padded/transformed prior to encryption via modular exponentiation with the public key.  However, the encryption result for each block is not necessarily a fixed length of bits, octets or characters. What are the accepted protocols for delimiting these encrypted blocks so that they can be decrypted with the private key?
Nobody (at least, nobody who does crypto seriously) splits up data into blocks to be independently encrypted with RSA. Not only is this inefficient, in CPU and in network bandwidth (because asymmetric encryption necessarily implies data enlargement), but we do not really know how "safe" it is. This is a little-studied question, so there is no accepted protocol for that.

Real-life protocols that use asymmetric encryption (e.g. CMS or OpenPGP) use hybrid encryption: the asymmetric algorithm is used to convey a symmetric key, which is then used with a symmetric encryption algorithm to process the bulk of the data. This has the extra advantage of also working with key exchange algorithms (like Diffie-Hellman) which are not asymmetric encryption algorithms (in a way, DH can be seen as an asymmetric encryption algorithm where you do not choose what you encrypt).

RSA-encrypting data "directly" is encountered mostly in protocols that must live under strict bandwidth constraints (e.g. in smart cards), where every single byte counts; but in that case, messages are very short, and there is no question of splitting messages into blocks.