Include JS WebCrypto raw format for openssl_get_publicKey

Description

With the inclusion of JS WebCrypto API, I believe it is necessary to support the exported raw format when client sends their own public EC keys to the server.

const { publicKey } = await crypto.subtle.generateKey({
  name : 'ECDH',  
  namedCurve : 'P-256'
}, true, ['deriveBits'])

const exported_key = new Uint8Array(await crypto.subtle.exportKey('raw', publicKey))

fetch('key.php', {
  method : 'post', 
  body :  btoa(String.fromCharCode(...exported_key))
}).then(e=>e.text())

However, openssl_pkey_get_public only accepts PEM formatted string. This would mean a whole lot of concatenating to do before we are able to get the public OpenSSLAsymmetricKey

$raw_format = base64_decode(file_get_content("php://input"));
// This header is only for P-256
$asn_1_header = pack('C*', ...[48, 89, 48, 19, 6, 7, 42, 134, 72, 206, 61, 2, 1, 6, 8, 42, 134, 72, 206, 61, 3, 1, 7, 3, 66, 0]);

var_dump(openssl_get_publicKey("-----BEGIN PUBLIC KEY-----\n".base64_encode($asn_1_header.$raw_format)."\n-----END PUBLIC KEY-----"));

It would be pretty cool to simplify it so that it becomes the following.

openssl_get_publicKey($raw_format);

I think alternatively we can make a new function for openssl to load what JS Web Crypto generated as "raw" type.

Note

I know that WebCrypto API does allow exporting SPKI key but that is besides the point. To add to this, when you subscribe to pushmanager, a p256dh is given in "raw" format as defined by WebCrypto API.

从 openssl_get_publicKey 和 openssl_pkey_get_public 入口开始，检查当前如何接受 OpenSSL 公钥。确定应如何识别和支持原始 WebCrypto EC 公钥输入，包括所述的 P-256 示例；完成的标准是原始输入无需手动进行 ASN.1 或 PEM 封装即可生成 OpenSSLAsymmetricKey。