Here's a quick example on how to use sodium_crypto_sign_detached(); where you have a message that you want to sign, so anyone with the public key can confirm that the message hasn't been tampered with.
This is similar to sodium_crypto_sign(), but the returned string does not contain the original message, it is just a signature.
<?php
// $sign_seed = random_bytes(SODIUM_CRYPTO_SIGN_SEEDBYTES);
// $sign_pair = sodium_crypto_sign_seed_keypair($sign_seed);
$sign_pair = sodium_crypto_sign_keypair();
$sign_secret = sodium_crypto_sign_secretkey($sign_pair);
$sign_public = sodium_crypto_sign_publickey($sign_pair);
//--------------------------------------------------
// Person 1, signing
$message = 'Hello';
$signature = sodium_crypto_sign_detached($message, $sign_secret);
//--------------------------------------------------
// Person 2, verifying
$message_valid = sodium_crypto_sign_verify_detached($signature, $message, $sign_public);
if (!$message_valid) {
exit('Message has been changed.');
}
?>
sodium_crypto_sign_detached
(PHP 7 >= 7.2.0, PHP 8)
sodium_crypto_sign_detached — Sign the message
说明
Sign a message with a secret key, that can be verified by the corresponding public key. This function returns a detached signature.
参数
-
message -
Message to sign.
-
secret_key -
Secret key. See sodium_crypto_sign_secretkey()
返回值
Cryptographic signature.
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User Contributed Notes 2 notes
craig at craigfrancis dot co dot uk ¶
6 years ago
cb at dialogs dot com ¶
4 years ago
For those(like me) confused by sodium_crypto_sign() vs. sodium_crypto_sign_detached()
From the libsodium docs https://libsodium.gitbook.io/doc/public-key_cryptography/public-key_signatures
The crypto_sign() function prepends a signature to a message "Combined mode"
In "detached mode" the signature is stored without attaching a copy of the original message to it.
