EME-OAEP decoding by reversing the Feistel network using previously determined mask generation function (MGF1) and SHA-1 hashing. A matrix of octets is provided as the input (EM) which is the output of EME-OAEP encoding (see problem 44964/below link 7.1.2 page 21). The label (L) is not provided or checked against the encoded label. No error checks should be conducted. Output should be the character string represented by the octets.

For example:

EM = [0,167,202,74,98,63,234,235,44,82,53,39,70,214,204,79,45,80,35,147,55,32,35,39,45,...
87,180,129,63,219,223,165,72,19,131,160,131,131,107,231,157,238,213,10,237,132,55,...
35,182,202,151,21,82,130,121,35,14,35,75,255,236,72,45,210,0,243,57,43,137,79,9,...
217,83,81,227,171,156,105,168,121,224,201,41,98,84,79,3,247,109,100,214,227,120,...
148,12,50,108,248,32,94];%input
M = 'I like to swim.';%output

https://www.emc.com/collateral/white-papers/h11300-pkcs-1v2-2-rsa-cryptography-standard-wp.pdf