One of the big issues with Textook RSA is that it really is what's in most textbooks as being RSA, and then corrected in a later section. For example "Cryptogra

One of the big issues with Textook RSA is that it really is what's in most textbooks as being RSA, and then corrected in a later section. For example "Cryptography Engineering" by Schneier, Ferguson, & Tohno does this, introducing RSA without padding in section 12.4 "RSA Defined" and then spends a page or so correcting the issues in section 12.5 "Pitfalls Using RSA. So of course someone going back to the definition when trying to implement something is going to miss the discussion about padding, as it's 5+ pages away! I feel it would be better to simply define RSA encryption as follows: First, generate key pairs, exchange public keys, etc. Then, apply a padding function to your plaintext. The definition of a padding function can be found in section <Section number>. Then compute c = m^e (mod n). Send the resulting ciphertext c to the other party. The padding discussion can still be located outside the definition of the mathematics, but the need to perform the padding is integral to this definition of RSA encryption.