Java language demo

import cn.hutool.core.util.HexUtil;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.text.SimpleDateFormat;
import java.time.LocalDateTime;
import java.util.Date;
import java.util.TimeZone;

public class SignatureDemo {

    private final static String PARTNER_CODE = "AKIDz8krbsJ5yKBZQpn74WFkmLPx3*******";
    private final static String PARTNER_TOKEN = "Gu5t9xGARNpq86cd98joQYCN3*******";
    private final static Charset UTF8 = StandardCharsets.UTF_8;
    private final static String SECRET_ID = PARTNER_CODE;
    private final static String SECRET_KEY = PARTNER_TOKEN;

    // prod
//    private final static String HOST = "api.klavi.ai";

    // dev
    private final static String HOST = "api-testing.klavi.ai";

    public static void main(String[] args) throws Exception {
//        buildGetInstitutionListSignature();
        buildSubmitCredentialsSignature();
//        buildCheckStatusSignature();
//        buildSubmitMFAInfoSignature();
//        buildUpdateProductsSignature();
//        buildDeleteAccountSignature();
    }

    private static void buildGetInstitutionListSignature() throws Exception {
        String httpRequestMethod = "GET";
        String canonicalUri = "/link/external/v2/getInstitutionList";
        String canonicalQueryString = "";
        String canonicalHeaders = "content-type:application/x-www-form-urlencoded\n" + "host:" + HOST + "\n";
        String signedHeaders = "content-type;host";
        String payload = "";
        String timestamp = getTimestamp();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
        String date = sdf.format(new Date(Long.valueOf(timestamp + "000")));

        buildSignature(httpRequestMethod, canonicalUri, canonicalQueryString, canonicalHeaders, signedHeaders,
                payload, date, timestamp);
    }

    private static void buildSubmitCredentialsSignature() throws Exception {
        String httpRequestMethod = "POST";
        String canonicalUri = "/link/external/v2/submitCredentials";
        String canonicalQueryString = "";
        String canonicalHeaders = "content-type:application/json;charset=UTF-8\n" + "host:" + HOST + "\n";
        String signedHeaders = "content-type;host";
        String payload = "{\"cpf\":\"aw/6B0KMZRVbBIdUp0uB/pZz97ZJfJgO4LaBRm7bBvRTo25HNwW0GkcELlFuMuw0krXDQO9gLqat49LA" +
                "/tgofERQrOJe0saTJt0bgue3FLSgjPP06HLdCHMgY2ApwUlIO/1otGuNYMa+m7zeT7+Cs3zEscPfwU3bC4pz39zLwNM=\"," +
                "\"agency\":\"DvZXoz6wMQHfys81ak4GHK+A2/F3ClQ7rV2JxXEGDDBjenQG3rb/MvX" +
                "+PKTLaUCiL92ym2bEkfEzvkzJTvdQuZV1dXwyVjbsSByFA" +
                "+JbOcRdn0LtyFxcJzYLmPUwnwAVarWhKiwguE2cNbKqpdxmxkGVAN6g2ghnC4zNPpXFsYA=\"," +
                "\"account\":\"evltwIAmaE12SPDKwKspH9D9PDA9HbAXq1xkaMShZflWPCIwODyXZx6alFAz7U443ZZX0wfuMc" +
                "+IHcFBKYvjDFoVds0NfQjVfBvx2lcj/WXx9ZQpUjkUsOfbZnfUg2SW79Y5Y7PEaPFxsKgYXb1yZNRQwvmLLrbRZyDDxNnDnIA" +
                "=\",\"password\":\"XfGzloZbejN+S/4+be31aJr8HWdImYuMUZkn1nudYHwVvzvM4se6CH89gekXOUFvn1w" +
                "/VFWHu1JHBEIoiP57Qc3eJ1YbnddKl0Px1QqwVVW/+9shxbPmNoM36WY6Uebn/kxB0iGlsyhNytyBwVPyjow298" +
                "/UMuNw0PRe7esZKSo=\",\"institutionCode\":\"237\"," +
                "\"accountLevel\":\"VmWC5cxnerhoiEAD4sYNEmjEmG87XYymV6f1MSULPY8ETnRN" +
                "+SQM3eUAKUshL6k05JGtkkKfou52RsCYa7Mtec8ZurRdx6k6C1+dRNyZmsrVl9OtQBtvwxgtdlENgzRaombKH" +
                "/18kxnDPEBXCBf3FV7dtRaXL7j6CXFq3O86a4g=\"}\n";
        String timestamp = getTimestamp();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
        String date = sdf.format(new Date(Long.valueOf(timestamp + "000")));

        buildSignature(httpRequestMethod, canonicalUri, canonicalQueryString, canonicalHeaders, signedHeaders,
                payload, date, timestamp);
    }

    private static void buildCheckStatusSignature() throws Exception {
        String httpRequestMethod = "GET";
        String canonicalUri = "/link/external/v2/checkStatus";
        String canonicalQueryString = "traceId=kJuktDQkvHezWtYyiPYOKwxr2ddByeb8";
        String canonicalHeaders = "content-type:application/x-www-form-urlencoded\n" + "host:" + HOST + "\n";
        String signedHeaders = "content-type;host";
        String payload = "";
        String timestamp = getTimestamp();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
        String date = sdf.format(new Date(Long.valueOf(timestamp + "000")));

        buildSignature(httpRequestMethod, canonicalUri, canonicalQueryString, canonicalHeaders, signedHeaders,
                payload, date, timestamp);
    }

    private static void buildSubmitMFAInfoSignature() throws Exception {
        String httpRequestMethod = "POST";
        String canonicalUri = "/link/external/v2/submitMFAInfo";
        String canonicalQueryString = "";
        String canonicalHeaders = "content-type:application/json;charset=UTF-8\n" + "host:" + HOST + "\n";
        String signedHeaders = "content-type;host";
        String payload = "{\"traceId\":\"kJuktDQkvHezWtYyiPYOKwxr2ddByeb8\"," +
                "\"code\":\"mb6kW19VXYU9ZvRb3TzUJ0jeei2ACETOZkt67J5zBTIbDW" +
                "+7Y3qnq7WI3gHckFCsebGxArhobZ78ZhTVOZpApiJ9fBUXA7AX3b9LK8daCHtAodQquT6TcW0Flt2v305ELB4HGNwLFR3EO9L" +
                "/vX5UU1VjSe3+pGGJFl7y554nwmM=\"}";
        System.out.println(payload);
        String timestamp = getTimestamp();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
        String date = sdf.format(new Date(Long.valueOf(timestamp + "000")));

        buildSignature(httpRequestMethod, canonicalUri, canonicalQueryString, canonicalHeaders, signedHeaders,
                payload, date, timestamp);
    }

    private static void buildUpdateProductsSignature() throws Exception {
        String httpRequestMethod = "POST";
        String canonicalUri = "/link/external/v2/updateProducts";
        String canonicalQueryString = "";
        String canonicalHeaders = "content-type:application/json;charset=UTF-8\n" + "host:" + HOST + "\n";
        String signedHeaders = "content-type;host";
        String payload = "{\"connectionKey\":\"1033b652e0c84acab018a9482cae3176\"}";
        String timestamp = getTimestamp();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
        String date = sdf.format(new Date(Long.valueOf(timestamp + "000")));

        buildSignature(httpRequestMethod, canonicalUri, canonicalQueryString, canonicalHeaders, signedHeaders,
                payload, date, timestamp);
    }

    private static void buildDeleteAccountSignature() throws Exception {
        String httpRequestMethod = "POST";
        String canonicalUri = "/link/external/v2/deleteAccount";
        String canonicalQueryString = "";
        String canonicalHeaders = "content-type:application/json;charset=UTF-8\n" + "host:" + HOST + "\n";
        String signedHeaders = "content-type;host";
        String payload = "{\"connectionKey\":\"1033b652e0c84acab018a9482cae3176\"}";
        String timestamp = getTimestamp();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
        String date = sdf.format(new Date(Long.valueOf(timestamp + "000")));

        buildSignature(httpRequestMethod, canonicalUri, canonicalQueryString, canonicalHeaders, signedHeaders,
                payload, date, timestamp);
    }

    private static void buildSignature(String httpRequestMethod, String canonicalUri, String canonicalQueryString,
                                       String canonicalHeaders,
                                       String signedHeaders, String payload, String date, String timestamp) throws Exception {
        String algorithm = "K1-HMAC-SHA256";
        String service = "cbms";

        // step 1: build canonical request string
        System.out.println(payload);
        String hashedRequestPayload = sha256Hex(payload);
        String canonicalRequest = httpRequestMethod + "\n" + canonicalUri + "\n" + canonicalQueryString + "\n"
                + canonicalHeaders + "\n" + signedHeaders + "\n" + hashedRequestPayload;
        System.out.println("**********canonicalRequest**********");
        System.out.println(canonicalRequest);

        // step 2: build string to sign
        String credentialScope = date + "/" + service + "/" + "k1_request";
        String hashedCanonicalRequest = sha256Hex(canonicalRequest);
        String stringToSign = algorithm + "\n" + timestamp + "\n" + credentialScope + "\n" + hashedCanonicalRequest;
        System.out.println("\n\n**********stringToSign**********");
        System.out.println(stringToSign);

        // step 3: sign string
        byte[] secretDate = hmac256(("K1" + SECRET_KEY).getBytes(UTF8), date);
        System.out.println("secretDate:" + HexUtil.encodeHexStr(secretDate));
        byte[] secretService = hmac256(secretDate, service);
        System.out.println("secretService:" + HexUtil.encodeHexStr(secretService));
        byte[] secretSigning = hmac256(secretService, "k1_request");
        System.out.println("secretSigning:" + HexUtil.encodeHexStr(secretSigning));
        String signature = DatatypeConverter.printHexBinary(hmac256(secretSigning, stringToSign)).toLowerCase();
        System.out.println("\n\n************signature:" + signature);

        // step 4: build authorization
        String authorization = algorithm + " " + "Credential=" + SECRET_ID + "/" + credentialScope + ", "
                + "SignedHeaders=" + signedHeaders + ", " + "Signature=" + signature;
        System.out.println("************authorization:" + authorization);
    }

    private static byte[] hmac256(byte[] key, String msg) throws Exception {
        Mac mac = Mac.getInstance("HmacSHA256");
        SecretKeySpec secretKeySpec = new SecretKeySpec(key, mac.getAlgorithm());
        mac.init(secretKeySpec);
        return mac.doFinal(msg.getBytes(UTF8));
    }

    private static String sha256Hex(String s) throws Exception {
        MessageDigest md = MessageDigest.getInstance("SHA-256");
        byte[] d = md.digest(s.getBytes(UTF8));
        return DatatypeConverter.printHexBinary(d).toLowerCase();
    }

    private static String getTimestamp() {
        return String.valueOf(System.currentTimeMillis() / 1000);
    }

}