@Override
  public byte[] encrypt(final byte[] plaintext, final byte[] contextInfo)
      throws GeneralSecurityException {
    byte[] ciphertext = noPrefixEncrypt(plaintext, contextInfo);
    if (outputPrefix.length == 0) {
      return ciphertext;
    }
    return com.google.crypto.tink.subtle.Bytes.concat(outputPrefix, ciphertext);
  }
Hybrid Public Key Encryption (HPKE) encryption.

<p>HPKE RFC: https://www.rfc-editor.org/rfc/rfc9180.html
java_src/src/main/java/com/google/crypto/tink/hybrid/internal/HpkeEncrypt.java