Ramp Signature Description

## Signature Parameters
ElementDescriptionRemarks
timestampThirteen-digit timestamp1538054050234
httpMethodRequest Method GET/POSTrequest method must be in uppercase.
requestPathRequest Pathon ramp：/index/rampPageBuy
off ramp:   /index/rampPageSell
bodyStringbodyStringGET：empty
POST：body parameters
## Step 1: Generate An Encrypted String
The signature string is fixed as follows: timestamp + httpMethod + requestPath + bodyString.
For the parameters in requestPath, sort them in dictionary order and remove any empty values.
Finally, encrypt using HMAC SHA256 with the SecretKey and encode it using Base64 to obtain the sign.
### On Ramp Example：
request link：`https://ramptest.alchemypay.org?appId=f83Is2y7L425rxl8&crypto=USDT&network=ETH&showTable=buy&fiat=USD&fiatAmount=30&timestamp=1538054050234&sign=JY9JcOwBosncT19Nn9DIfTH%2BvfSt6xL%2BI%2BRVCl9YGgE%3D`
httpMethod：GET
requestPath：/index/rampPageBuy
bodyString： 
Signature String ：
`1538054050234GET/index/rampPageBuy?appId=f83Is2y7L425rxl8&crypto=USDT&fiat=USD&fiatAmount=30&network=ETH&showTable=buy&timestamp=1538054050234`
### Off Ramp Example
request link：`https://ramptest.alchemypay.org?appId=f83Is2y7L425rxl8&crypto=USDT&network=ETH&showTable=sell&fiat=USD&cryptoAmount=30&timestamp=1538054050234&sign=615hNootKL4aScndVHxqRnuZzoLDCJU%2FBzhHj913qlk%3D`
timestamp：1538054050234
httpMethod：GET
requestPath：/index/rampPageSell
bodyString： 
Signature String：
`1538054050234GET/index/rampPageSell?appId=f83Is2y7L425rxl8&crypto=USDT&cryptoAmount=30&fiat=USD&network=ETH&showTable=sell&timestamp=1538054050234`
## Step Two: Generate Your Signature
Use the encrypted string and secret as parameters to generate a signature as follows
﻿
​x
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package v4.onramp;
​
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.Map;
import java.util.TreeMap;
import java.util.stream.Collectors;
//example for onramp
public class V4OnrampPage{
​
    public static void main(String[] args) throws Exception {
        // Generate current timestamp in milliseconds
        String timestamp = String.valueOf(System.currentTimeMillis());
        String httpMethod = "GET";
        String requestPath = "/index/rampPageBuy";// onramo:/index/rampPageBuy offramp:/index/rampPageSell
        String secretKey = "*****"; // relpace with your secretKey
        String appId = "*****"; // relpace with your appId
        //Replace with the token from the getToken API.
        //String token = "****";
        // Request parameters
        Map<String, String> paramsToSign = new TreeMap<>();
        paramsToSign.put("crypto", "USDT");
        //paramsToSign.put("token", token);
﻿