ScreenFilterMonitorImpl.java 文件源码

private boolean isPlayServices(String pkg) {
    if (!PLAY_SERVICES_PACKAGE.equals(pkg)) return false;
    try {
        PackageInfo sigs = pm.getPackageInfo(pkg, GET_SIGNATURES);
        // The genuine Play Services app should have a single signature
        Signature[] signatures = sigs.signatures;
        if (signatures == null || signatures.length != 1) return false;
        // Extract the public key from the signature
        CertificateFactory certFactory =
                CertificateFactory.getInstance("X509");
        byte[] signatureBytes = signatures[0].toByteArray();
        InputStream in = new ByteArrayInputStream(signatureBytes);
        X509Certificate cert =
                (X509Certificate) certFactory.generateCertificate(in);
        byte[] publicKeyBytes = cert.getPublicKey().getEncoded();
        String publicKey = StringUtils.toHexString(publicKeyBytes);
        return PLAY_SERVICES_PUBLIC_KEY.equals(publicKey);
    } catch (NameNotFoundException | CertificateException e) {
        if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
        return false;
    }
}