signing.pub

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAmKdQSV+JwuIQF+t1iISu
kHNffIDWMcr6v8L9CI1U+9LOF1xNPw7IlhubU+nLWUqGxKnFfadkB7lQCthoK+lb
wbVCUmUXx3vao8N61BWwWLJtlvZdp5Pz2oMQzadzIU4swzIZtTg3uPHtx+p3y5Yc
EKkDk3hMcEPWLzvIxSmgDTlI8HSehX7QCM29hXUpl9iXXnAAcipXQtOktmWaU731
X4SMs93XIFlW2ujyde7zvd3/XTmQWTwYPQhk+OyYIBRFWijOrXGp9q5Vbz5Z+XHY
1esaH64xfiZZON6xLAWqh3AadqXSEJy0gqmg2MOu0CD1RgPT+mAiVXbayHWe3GnY
bwIDAQAB
-----END PUBLIC KEY-----

verify_signature.php

<?php

//signed data
$data      = 's3://my-bucket-name/path/a/b/c.csv';
// signed signature generated from private key
$signature = "JRcF4pkIHDSiALk/wulQaomLjSX95hrhke7Edcce8vXBxQuwpoXUw/tf0tIWAs+bMU+8LTgB7eQIWhKDj8A49FOd2C8Ez+2bSozWZdrGpYVJ1d5BmwYfKMMLmLZm/wnXwNomuuCQTsB+vSDuWj4Yq4j8d3bU8A7+KERJpQM2ZdWu2XBs/vmpjSG4JYcwf2OcZuduDCsIBTR0tAiqr2hOZnsSIDYQ9v6Fs950hmCTBraCxbPqgcrMFcTgQPCR/ZEQ/oUjuZLN/kteF+1XbmMmKnJ/0fs/542TkKU02nMJUaYqFKtr2CIYVMvpQbjO3JOC+hmwKW8mekfaekkoAf+Mhw==";

// read public key from local storage
$c              = file_get_contents("signing.pub");
$public_key_res = openssl_pkey_get_public($c);


// verify signature is signed for the $data 
$ok = openssl_verify($data, $signature, $public_key_res, OPENSSL_ALGO_SHA1);
if ($ok == 1) {
    echo "the data is from legit sender";
} elseif ($ok == 0) {
    echo "someone try to hijack";
} else {
    echo "error: " . openssl_error_string();
}