google-cloud-kms PKCS7加密消息语法

Question

是否有人使用Google的HSM和KMS服务实现了加密消息语法？

很难说这个功能是否内置于Tink库中。

没有针对OpenSSL或BoringSSL的谷歌引擎(如果不是这样的话，我希望得到纠正)，并且由于引擎需要用clang编写，我想包括tink.so库是相当困难的？

如果任何人有任何关于在Google的KMS服务上执行这些类型的操作的信息，将不胜感激。

Answer 1

目前，这将需要相当数量的自定义代码，尽管这在技术上是可能的。该功能没有内置到Tink中，也没有适用于OpenSSL或BoringSSL的云KMS引擎。

也许最简单的方法是在Bouncycastle中使用带有CMS支持的Cloud KMS Java客户端，尽管我不确定Java是否适合您的用例。如果你觉得有用的话，我可以写一个例子来说明如何做到这一点。

Answer 2

感谢您的指导@bdhess！

我为那些有兴趣尝试类似功能的人提供了一些代码片段。需要注意的主要类是ContentSignerFactory.java，这是应用程序接口魔术发生的地方。

对于bouncycastle有一个非常有用的pdf：https://www.bouncycastle.org/fips-java/BCFipsIn100.pdf

注意:我不是一名程序员

Cms.java

public class Cms {
    public static byte[] signDataKms(
            String credentialsKeyPath,
            String keyName,
            X509Certificate signingCert,
            byte data[]) throws Exception {

        List<X509Certificate> certList = new ArrayList<>();
        certList.add(signingCert);
        Store certs = new JcaCertStore(certList);

        CMSTypedData cmsData = new CMSProcessableByteArray(data);

        DigestCalculatorProvider digProvider =
                new JcaDigestCalculatorProviderBuilder().setProvider("BC").build();
        JcaSignerInfoGeneratorBuilder signerInfoGeneratorBuilder =
                new JcaSignerInfoGeneratorBuilder(digProvider);

        //SignedHash is a base64-encoded PKCS1 block.
        ContentSigner sha1Signer = ContentSignerFactory.getContentSigner((stream) -> {
            try {
                return Kms.signAsymmetric(credentialsKeyPath, keyName, stream.toByteArray());
            } catch (IOException e) {
                e.printStackTrace();
            } catch (NoSuchAlgorithmException e) {
                e.printStackTrace();
            }
            return new byte[0];
        }, "SHA256WITHRSA");

        CMSSignedDataGenerator gen = new CMSSignedDataGenerator();

        gen.addSignerInfoGenerator(signerInfoGeneratorBuilder.build(sha1Signer, signingCert));
        gen.addCertificates(certs);
        CMSSignedData cms = gen.generate(cmsData, true);

        return cms.toASN1Structure().getEncoded(ASN1Encoding.DER);
    }
}

ContentSignerFactory.java

public class ContentSignerFactory {

    public static ContentSigner getContentSigner(Function<ByteArrayOutputStream, byte[]> lambda, String algorithm) {
        return new ContentSigner() {
            //This is to ensure that signature is created using the right data.
            ByteArrayOutputStream stream = new ByteArrayOutputStream();

            @Override
            public byte[] getSignature() {
                //Calling HSM here instead, the stream is the AttributeMap
                byte[] data = lambda.apply(stream);
                return data;
            }

            //Perhaps called by BouncyCastle library to provide the content
            @Override
            public OutputStream getOutputStream() {
                return stream;
            }

            @Override
            public AlgorithmIdentifier getAlgorithmIdentifier() {
                return new DefaultSignatureAlgorithmIdentifierFinder().find(algorithm);
            }
        };
    }
}

Kms.java

public class Kms {
    public static byte[] signAsymmetric(String credentialsKeyPath, String keyName, byte[] message)
            throws IOException, NoSuchAlgorithmException {
        // Create the Cloud KMS client.
        try (KeyManagementServiceClient client
                     = KeyManagementServiceClient.create(getKeyManagementServiceSettings(credentialsKeyPath))) {

            // Note: some key algorithms will require a different hash function
            // For example, EC_SIGN_P384_SHA384 requires SHA-384
            byte[] messageHash = MessageDigest.getInstance("SHA-256").digest(message);

            AsymmetricSignRequest request = AsymmetricSignRequest.newBuilder()
                    .setName(keyName)
                    .setDigest(Digest.newBuilder().setSha256(ByteString.copyFrom(messageHash)))
                    .build();

            AsymmetricSignResponse response = client.asymmetricSign(request);
            return response.getSignature().toByteArray();
        }
    }
}