Implement the ChaCha20 and ChaCha20-Poly1305 ciphers as specified in RFC 7539. ChaCha20 is a newer stream cipher that can replace the older, insecure RC4 stream cipher.

Those wishing to obtain an instance of the ChaCha20 stream cipher may use the algorithm string "ChaCha20" with the `Cipher.getInstance` method. Those wishing to use ChaCha20 in AEAD mode with the Poly1305 authenticator may use the algorithm string "ChaCha20-Poly1305". See the "Java Security Standard Algorithm Names" document for more details.