EME-OAEP encoding of input message using a Feistel network with SHA-1 hashing within the mask generation function (MGF1) (see problem 44963/below link 7.1.1 page 18). Inputs will include message (M), label (L), a random seed (seed) array of octets of length 20 (needed such that outputs can be compared), and output length (k). Output (EM) array will be an array of octets of length, k. Hash length will always be 20 for SHA-1 (160-20 bytes). The character length of input message will never exceed k-42.

For example:

M = 'I like to swim.';%input
L = 'abcdefghijklmnopqrstuvwxyz';%input
seed = [147,11,108,119,5,16,236,136,93,93,38,38,89,86,200,124,118,33,226,172];%input
k = 100;%input
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];%output

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