PKCS#1 ver 2 padding

pkcs1v2pad.ml

let pkcs1v2pad key msg =
	let blen = key.RSA.size/8
	and mlen = String.length msg
	and zero = char_of_int 0
	and rnd = Random.string Random.secure_rng in
	let padlen = blen - mlen in
	if padlen > 3 then begin
		let res = rnd padlen in
		res.[0] <- (char_of_int 0);
		res.[1] <- (char_of_int 2);
		res.[padlen - 1] <- (char_of_int 0);
		for i = 2 to padlen - 2 do
			while res.[i] = zero do res.[i] <- (rnd 1).[0] done
		done;
		res ^ msg
	end
	else msg
;;