RFR: 8325513: Export method for Cipher [v3]

[Weijun Wang]

On Fri, 10 May 2024 14:00:55 GMT, Weijun Wang <weijun at openjdk.org> wrote:

>> Add `Cipher::export` API.
>
> Weijun Wang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   change new method to non final

I don't think it's worth inventing a new cryptographic engine for HPKE and it _is_ a cipher.

        var g = KeyPairGenerator.getInstance("X25519");
        var kp = g.generateKeyPair();
        var sender = Cipher.getInstance("HPKE");
        var params = HPKEParameterSpec.of()
                .info("this_info".getBytes(StandardCharsets.UTF_8));
        sender.init(Cipher.ENCRYPT_MODE, kp.getPublic(), params);
        var receiver = Cipher.getInstance("HPKE");
        receiver.init(Cipher.DECRYPT_MODE, kp.getPrivate(), params.encapsulation(sender.getIV()));
        var msg = "Hello World".getBytes(StandardCharsets.UTF_8);
        var ct = sender.doFinal(msg);
        var pt = receiver.doFinal(ct);

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PR Comment: https://git.openjdk.org/jdk/pull/18409#issuecomment-2111349767