Function oaep_encrypt 

pub(crate) fn oaep_encrypt<R: CryptoRngCore + ?Sized>(
    rng: &mut R,
    msg: &[u8],
    digest: &mut dyn DynDigest,
    mgf_digest: &mut dyn DynDigest,
    label: Option<String>,
    k: usize,
) -> Result<Zeroizing<Vec<u8>>>

Encrypts the given message with RSA and the padding scheme from PKCS#1 OAEP.

The message must be no longer than the length of the public modulus minus 2 + (2 * hash.size()).