sodium_crypto_box

Authenticated public-key encryption

&reftitle.description; `string` `sodium_crypto_box` `string` `message` `string` `nonce` `string` `key_pair`

Encrypt a message using asymmetric (public key) cryptography.

The algorithm used by functions prefixed with `sodium_crypto_box` are Elliptic Curve Diffie-Hellman over the Montgomery curve, Curve25519; usually abbreviated as X25519.

&reftitle.parameters;

`message`

- The message to be encrypted.

`nonce`

- A number that must be only used once, per message. 24 bytes long. This is a large enough bound to generate randomly (i.e. `random_bytes`).

`key_pair`

- See `sodium_crypto_box_keypair_from_secretkey_and_publickey`. This should include the sender's X25519 secret key and the recipient's X25519 public key.

&reftitle.returnvalues;

Returns the encrypted message (ciphertext plus authentication tag). The ciphertext will be 16 bytes longer than the plaintext, and a raw binary string. See `sodium_bin2base64` for safe encoding for storage.