问 我试图从X509Certificate扩展中解码和提取八进制字符串，但是没有得到任何有效的字符串。

EN

我一直试图按照 server?language=objc 中提到的步骤解码八进制字符串。

以下是我尝试过的：

        X509Certificate cert1 = getParentCertificate(new String(decodedCredCert));
        System.out.println(cert1);
        cert1.checkValidity(); // verify against apple app attest root ca
        byte[] ext = cert1.getExtensionValue("1.2.840.113635.100.8.2");
        ASN1InputStream bIn = new ASN1InputStream(ext);
        ASN1Primitive obj = bIn.readObject();
        ASN1OctetString string = (ASN1OctetString) obj;
        byte[] octs = string.getOctets();
        ASN1InputStream dIn = new ASN1InputStream(octs);