PHP SHA256WithRSA签名和验签

//生成 sha256WithRSA 签名
function getSign($content, $privateKey){
    $privateKey = "-----BEGIN RSA PRIVATE KEY-----\n" .
        wordwrap($privateKey, 64, "\n", true) .
        "\n-----END RSA PRIVATE KEY-----";

    $key = openssl_get_privatekey($privateKey);
    openssl_sign($content, $signature, $key, "SHA256");
    openssl_free_key($key);
    $sign = base64_encode($signature);
    return $sign;
}

//验证 sha256WithRSA 签名
function verify($content, $sign, $publicKey){
    $publicKey = "-----BEGIN PUBLIC KEY-----\n" .
        wordwrap($publicKey, 64, "\n", true) .
        "\n-----END PUBLIC KEY-----";

    $key = openssl_get_publickey($publicKey);
    $ok = openssl_verify($content,base64_decode($sign), $key, 'SHA256');
    openssl_free_key($key);
    return $ok;
}

语法是这样的:
openssl_sign(“您要签名的数据”,”签名后返回来的数据”,”签名的钥匙/可以是公钥签名也可以是私钥签名,一般是私钥加密,公钥解密”)