Thread safety with RSA Cipher

Question

As the titles says, i would like to know how to best use Cipher instance in multi threaded environment given the RSA algorithm.

I have read a couple of questions on the

Answer 1

In case somebody else reads this, there shouldn't be need to reinitialize cipher for every call with RSA. Although, pool of ciphers could be used for performance boost.

I have written quick load test to verify this.

It seems that it is enough to synchronize on cipher.doInit() and use single Cipher instance for decryption.

private static Queue results = new ConcurrentLinkedQueue();

@Test
public void test() throws InterruptedException {

    String plainText = "some text to verify data integrity";

    String encryptedText = Encrypt.encrypt(plainText);


    for (int i = 0; i < 5000; i++) {

        new Thread( () -> { results.add(Decrypt.decrypt(encryptedText)); })
        .start();;          
    }

    Thread.sleep(5000);

    assertTrue(results.size() == 5000);

    while(!results.isEmpty()) {

        assertTrue(results.poll().equals(plainText));
    }
}