openssl_pkcs7_sign(): 文件 AppleWWDRCA.cer 中没有证书

openssl_pkcs7_sign(): no certificates in file AppleWWDRCA.cer

我需要创建一个分离的 PKCS7 签名以用于 Apple 钱包通行证。

代码

private function createSignature()
{
    $cert = '/etc/ssl/local.crt';
    $key = '/etc/ssl/local.key';
    $wwdr = '/var/www/app/storage/passes/AppleWWDRCA.cer';
    $headers = [
        'signing-time' => (new DateTime())->format('o-m-d H:i:s'),
    ];

    return openssl_pkcs7_sign("$this->dir/manifest.json", "$this->dir/signature",
        $cert, $key, $headers, PKCS7_DETACHED, $wwdr);
}

错误

openssl_pkcs7_sign(): no certificates in file, /var/www/app/storage/passes/AppleWWDRCA.cer

AppleWWDRCA.cer 是从 https://www.apple.com/certificateauthority/ 下载的。我下载的确切证书是 WWDR Certificate (Expiring 02/07/23)。我查看了该文件并确认它不是空白的。我错过了一步吗?

问题已通过将 AppleWWDR.cer 添加到我的钥匙串并将其作为 .pem 文件从钥匙串中导出来解决。