如何在SignatureChecker的verifyMessageSignature方法中提取publicKey属性

Question

我正在写和sns http终点。我必须使用SignatureChecker的verifyMessageSignature方法验证SNS消息。如何从消息中获取publicKey属性。是否有它的util方法。请帮忙。

Answer 1

来自亚马逊的SNS消息包含字段SigningCertURL。将此位置的字节读取为字符串cert，然后从中创建公钥：

/**
 * Build a PublicKey object from a cert
 *
 * @param cert the cert body
 * @return a public key
 */
private PublicKey makePublicKey(String cert) {
    try {
        CertificateFactory fact = CertificateFactory.getInstance("X.509");
        InputStream stream = new ByteArrayInputStream(cert.getBytes(StandardCharsets.UTF_8));
        X509Certificate cer = (X509Certificate) fact.generateCertificate(stream);
        return cer.getPublicKey();
    } catch (Exception e) {
        LOGGER.error("Failed to make a public key from Amazon cert", e);
        return null;
    }
}

然后你可以用它作为第二个参数调用signatureChecker.verifySignature。