Android Billing-in App version 3 verify in server - php

Question

I build Android app with billing-in app(version 3). I want verify purchase in my server PHP with openssl_verify().
I neet four values:
$data, $signature, $public_key and $SIGNATURE_ALGORITHM. I found a solution here, but it not understand to me in what form should be $data?
I get responseData in Android app:
'{
"orderId":"12999763169054705758.1371079406387615",
"packageName":"com.example.app",
"productId":"exampleSku",
"purchaseTime":1345678900000,
"purchaseState":0,
"developerPayload":"bGoa+V7g/yqDXvKRqq+JTFn4uQZbPiQJo4pf9RzJ",
"purchaseToken":"rojeslcdyyiapnqcynkjyyjh"
}'
I have signature from app.
How do I need to convert string so I can use it in the function php openssl_verify()?
Thanks.

Answer 1

I use in my project
public function verifySignatureTransaction($signed_data, $signature, $public_key_base64) {
$key = "-----BEGIN PUBLIC KEY-----\n" .
chunk_split($public_key_base64, 64, "\n") .
'-----END PUBLIC KEY-----';
//using PHP to create an RSA key
$key = openssl_pkey_get_public($key);
if ($key === false) {
throw new \InvalidArgumentException("Public key not valid");
}
$signature = base64_decode($signature);
//using PHP's native support to verify the signature
$result = openssl_verify(
$signed_data,
$signature,
$key,
OPENSSL_ALGO_SHA1
);
if (0 === $result) {
return false;
} else {
if (1 !== $result) {
return false;
} else {
return true;
}
}
}
And $signed_data its json string without formatting