sodium_crypto_secretbox
Authenticated shared-key encryption
Description
string sodium_crypto_secretbox(#[\SensitiveParameter]string $message, string $nonce, #[\SensitiveParameter]string $key)
Encrypt a message with a symmetric (shared) key.
Parameters
-
message
-
The plaintext message to encrypt.
-
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
-
Encryption key (256-bit).
Return Values
Returns the encrypted string.
Examples
Example #1 sodium_crypto_secretbox example
<?php
// The $key must be kept confidential
$key = sodium_crypto_secretbox_keygen();
// Do not reuse $nonce with the same key
$nonce = random_bytes(SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);
$plaintext = "message to be encrypted";
$ciphertext = sodium_crypto_secretbox($plaintext, $nonce, $key);
var_dump(bin2hex($ciphertext));
// The same nonce and key are required to decrypt the $ciphertext
var_dump(sodium_crypto_secretbox_open($ciphertext, $nonce, $key));
?>
The above example will output
something similar to:
string(78) "3a1fa3e9f7b72ef8be51d40abf8e296c6899c185d07b18b4c93e7f26aa776d24c50852cd6b1076"
string(23) "message to be encrypted"
See Also
- sodium_crypto_secretbox_open
- sodium_crypto_secretbox_keygen
- random_bytes