(PHP 7 >= 7.2.0, PHP 8)
sodium_crypto_secretbox_open — Authenticated shared-key decryption
sodium_crypto_secretbox_open(string $ciphertext, string $nonce, #[\SensitiveParameter] string $key): string|false
Decrypt an encrypted message with a symmetric (shared) key.
ciphertextMust be in the format provided by sodium_crypto_secretbox() (ciphertext and tag, concatenated).
nonceA 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()).
keyEncryption key (256-bit).
The decrypted string on success or false on failure.
nonce has a length of bytes different than SODIUM_CRYPTO_SECRETBOX_NONCEBYTES (24 bytes), a SodiumException will be thrown. key has a length of bytes different than SODIUM_CRYPTO_SECRETBOX_KEYBYTES (32 bytes), a SodiumException will be thrown. Example #1 sodium_crypto_secretbox_open() example
<?php
// The $key must be kept confidential
$key = random_bytes(SODIUM_CRYPTO_SECRETBOX_KEYBYTES);
// Do not reuse $nonce with the same key
$nonce = random_bytes(SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);
$ciphertext = sodium_crypto_secretbox('message to be encrypted', $nonce, $key);
// The same nonce and key are required to decrypt the $ciphertext
$plaintext = sodium_crypto_secretbox_open($ciphertext, $nonce, $key);
if ($plaintext !== false) {
echo $plaintext . PHP_EOL;
}
?> The above example will output:
message to be encrypted
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https://www.php.net/manual/en/function.sodium-crypto-secretbox-open.php