A modified version of the EMEOAEP module supplied by David J. Sankel (http://www.electronconsulting.com/rsa-haskell).
As the original code is GPL, this has to be. This code is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This code is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this code; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Take a mask generating function, a hash function, a label (which may be null), a random seed, the modulus of the key and the message and returns an encoded message. NB you could pass in the length of the modulus but it seems safer to pass in the modulus itself and calculate the length when required. See ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-1/pkcs-1v2-1.pdf for more details.