> For the complete documentation index, see [llms.txt](https://dev.fatpay.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dev.fatpay.org/appendix/demo/widget-signature-demo.md).

# Widget Signature Demo

Demo for \[[Widget Signature](/reference/integration-tutorial/widget-signature.md)]

{% tabs %}
{% tab title="Java" %}
{% hint style="success" %}
Please fill in your own info in the following codes.
{% endhint %}

```java
package onramp.widgetsign;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.security.*;
import java.util.*;

/**
 * SignUtil
 *
 * @author FaTPay
 */
public class SignUtil {

    private static final Logger LOG = LoggerFactory.getLogger(SignUtil.class);

    /**
     * secretKey
     */
    private static final String SECRET_KEY = "<YOUR SECRET KEY>";

    /**
     * partnerId
     */
    private static final String PARTNERID = "<YOUR PARTNER ID>";

    /**
     * walletAddress
     */
    private static final String WALLETADDRESS = "<YOUR WALLET ADDRESS>";

    /**
     * Converts parameters into ordered strings
     *
     * @param params
     * @return
     */
    private static String paramsToStr(Map<String, String> params) {
        StringBuilder param = new StringBuilder();
        List<String> keys = new ArrayList(params.keySet());
        // Sorts the specified keys
        Collections.sort(keys);
        int index = 0;
        Iterator<String> iterator = keys.iterator();
        while (iterator.hasNext()) {
            String key = iterator.next();
            String value = params.get(key);
            // Filter out null and empty values
            if ("x-fp-signature".equals(key) || "signature".equals(key) || "sign".equals(key) || StringUtils.isBlank(value)) {
                continue;
            }
            param.append(index == 0 ? "" : "&").append(key).append("=").append(value);
            index++;
        }
        return param.toString();
    }

    /**
     * Generates the HmacSHA256 signature
     *
     * @param secretKey
     * @param params
     * @return
     * @throws InvalidKeyException
     * @throws NoSuchAlgorithmException
     * @throws UnsupportedEncodingException
     */
    public static String generateSignature(String secretKey, Map<String, String> params) throws InvalidKeyException, NoSuchAlgorithmException, UnsupportedEncodingException {
        String signature = "";
        if (StringUtils.isBlank(params.get("partnerId")) || StringUtils.isBlank(params.get("walletAddress")) || StringUtils.isBlank(params.get("timestamp")) || StringUtils.isBlank(params.get("nonce")) || StringUtils.isBlank(secretKey)) {
            return signature;
        }
        String baseParamString = paramsToStr(params);

        Mac sha256Mac = Mac.getInstance("HmacSHA256");
        sha256Mac.init(new SecretKeySpec(secretKey.getBytes(), "HmacSHA256"));
        byte[] bytes = sha256Mac.doFinal(baseParamString.getBytes());
        signature = Base64.encodeBase64String(bytes);
        signature = urlEncode(signature);
        LOG.info("base:{} secretKey:{} sha256:{} base64:{}", baseParamString, secretKey, bytes.toString(), signature);
        return signature;
    }

    /**
     * urlEncode
     *
     * @param string
     * @return
     * @throws UnsupportedEncodingException
     */
    private static String urlEncode(String string) throws UnsupportedEncodingException {
        String encoded = URLEncoder.encode(string, "UTF-8").replace("+", "%20");
        return encoded;
    }

    // ******************** WIDGET SIGNATURE DEMO START ********************//
    public static void widgetDemo() {
        // Parameters to be signed
        Map<String, String> shaParamMap = new HashMap<>();
        shaParamMap.put("timestamp", "1661425554");
        shaParamMap.put("nonce", "166142");
        shaParamMap.put("partnerId", PARTNERID);
        shaParamMap.put("walletAddress", WALLETADDRESS);
        shaParamMap.put("walletAddressLocked", "1");
        shaParamMap.put("walletAddressHidden", "1");
        shaParamMap.put("ext", "ext");

        String hmacSHA256 = "";
        try {
            hmacSHA256 = SignUtil.generateSignature(SECRET_KEY, shaParamMap);
        } catch (Exception e) {
            LOG.error("sign error, exception:{}", e);
        }
        LOG.info(hmacSHA256);
    }
    // ******************** WIDGET SIGNATURE DEMO END ********************//
}


```

{% endtab %}

{% tab title="Node.js" %}

```javascript
const crypto = require('crypto');

var text = "original text to be signed";
var secretkey = "private key to generate sign";

// generate signature
var signature = crypto.createHmac('sha256', secretkey).update(text).digest("base64");
console.info("signature: " + signature);
```

{% endtab %}
{% endtabs %}


---

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