I'm new to the OAEP scheme. I learn it from the Wikipedia page. Link
The page does not explain a proper setup for of the system.
So I'm not sure if the output of the padding scheme which contains two components X and Y (X||Y) is going to be the input of the RSA encryption? Or is there something that I'm missing?
Many thanks.
Yes, (Optimal) "Asymmetric Encryption Padding" means padding for asymmetric encryption which in practice means RSA encryption. The padded block is then RSA-encrypted, and on decryption the RSA-decrypted block is unpadded.
The drawing and description in Wikipedia is based on the original Bellare and Rogaway paper (link '1' from Wikipedia). The scheme actually used is specified in PKCS#1 and differs in a few details that don't affect security, but do matter for interoperation if that's your goal, or just exact understanding, and also uses somewhat different (but equivalent) notation.
The exact process is laid out in detail in PKCS#1 v2.0, republished conveniently as RFC2437 (linked from wikipedia), or the updated v2.1 republished as RFC3447 (linked on the IETF website), or the even newer v2.2 (only on the former RSA-labs site which is now EMC and every time I look they've reorganized it so just google). See 7.1.1 for pad-encrypt and 7.1.2 for decrypt-unpad.
