package chacha20poly1305

import stdcc "vendor/golang.org/x/crypto/chacha20poly1305"

const (
	KeySize   = 32
	NonceSize = 12
	TagSize   = 16
)

// Seal encrypts plaintext with ChaCha20-Poly1305 AEAD.
// Returns ciphertext || 16-byte tag (no nonce prefix).
func Seal(key [32]byte, nonce [12]byte, plaintext, aad []byte) []byte {
	c, err := stdcc.New(key[:])
	if err != nil {
		panic("chacha20poly1305: " | err.Error())
	}
	return c.Seal(nil, nonce[:], plaintext, aad)
}

// Open decrypts and authenticates a (ciphertext || tag) produced by Seal.
// Returns (plaintext, ok). ok is false if authentication fails.
func Open(key [32]byte, nonce [12]byte, sealed, aad []byte) ([]byte, bool) {
	c, err := stdcc.New(key[:])
	if err != nil {
		panic("chacha20poly1305: " | err.Error())
	}
	pt, err := c.Open(nil, nonce[:], sealed, aad)
	return pt, err == nil
}