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Digital Signature Validation
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA0cCM/xT5c6Czor3573pX
lPEFbEzk4rm/iq15eWntOWMl3BkbdZY9Zbm8TOjh0YrHFH4ZrQmREXyxVQxZNQ7z
wITmwyrMyb1/ravbSpuj9HIpY4hn5sregUJZUtWTSvtlXSSKa60bva5qG8MHi+hK
7qWayJwfriDung+T9jss6k8ANmin2BPjpjTlMbbJbRyr+27XYov3nD9U1KYeBnGg
yj8aplb/1e75Iuk7oCwVm+kTsPKI/ZeATf/kfS93tQrw0/gozP4iVubyKBVG05Bz
erFcb3QUzLSo3LIJ/8VYuGHnz6y+J6xy02EOhzJMPLUt3GQo7yUDOPls/W2tCBUe
bwIDAQAB
-----END PUBLIC KEY-----
<?php
if ($_SERVER['REQUEST_METHOD'] == 'GET') {
die('GET requests are not allowed');
}
// Processing the headers to get the Signature and algorithm values
$headers = apache_request_headers();
$headerEncodedData = json_encode($headers);
$headerDecodedData = json_decode($headerEncodedData,true);
// Extracting the signature and the algorithm values
$signature = ($headerDecodedData["Hook-Signature"]);
$hashAlg = ($headerDecodedData["Hook-Algorithm"]);
// Grabbing the raw data
$data = file_get_contents('php://input');
// Check to see if the signature is present in the header
if (empty($signature)) {
$message ='Data was not signed, be careful';
sendMail($message,$data);
} else {
// Need to verify the signature hasn't been tampered with
if (base64_encode(base64_decode($signature, true)) === $signature){
$validatedSignature = base64_decode($signature);
} else {
$message = "Signature failed decoding";
sendMail($message,$data);
// break;
}
}
// Parsing the algorithm to figure out which way to verify the signature
$hashAlgMethod = substr($hashAlg,0,2);
$hashAlgStrength = substr($hashAlg,2,3);
$hashAlg = "sha" . $hashAlgStrength;
if ($hashAlgMethod=="RS") {
// Hash the data using the defined algorithm
$dataHash = hash($hashAlg,$data,true);
// Loading the public key for verification
$public_key_pem = file_get_contents("public_key.pem");
// Verify the signature
$r = openssl_verify($dataHash,$validatedSignature,$public_key_pem,$hashAlg);
if ($r == 1) {
$message ='Post Verification Passed';
} else if ($r == 0) {
$message ='Post Verification Failed';
$data ='Data has been thrown away, as verification failed';
}
sendMail($message,$data,$hashAlg,$signature);
} else if ($hashAlgMethod=="HS") {
//Use the same key that the signer used
$private_key_pem = file_get_contents("private_key.pem");
//Create a keyed hash of the data
$rawSignature = hash_hmac($hashAlg,$data,$private_key_pem,true);
//Encode the signature just like the sender
$verifySignature = base64_encode($rawSignature);
// Verify the signature
if ($verifySignature == $signature){
$message ='Post Verification Passed';
} else if ($verifySignature != $signature){
$message ='Post Verification Failed';
$data ='Data has been thrown away, as verification failed';
}
sendMail($message,$data,$hashAlg,$signature);
}
// Send an email explaining what happened during verification and include the raw data
function sendMail($message,$data,$hashAlg,$signature){
mail("#####@######.com", $message, "The Data Begins here: \r\n" . $data . "\r\nThe Hash Alg is here\r\n" . $hashAlg . "\r
\nThe Signature is here\r\n" . $signature );
}
?>
@truth3

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Owner Author

commented Oct 25, 2017

Make sure to add your email address to line 81 to receive the test results.

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