1) 取本次请求的全部参数（不含 sign 自身）；
2) 按参数名 ASCII 升序排序，拼接成 k1=v1&k2=v2&…；
3) 末尾追加 &key=你的AppKey；
4) 对整串做 MD5 后转大写，即得 sign。

{
    "ok": 1,
    "msg": "查询成功，共3条记录，每页10条，当前第1\/1页",
    "keys": "厦门 工商",
    "pages": 1,
    "thispage": 1,
    "pagecount": 1,
    "count": 3,
    "list": [
        {
            "bankname": "中国工商银行",
            "name": "中国工商银行股份有限公司厦门嘉禾支行",
            "code": "102393000077",
            "provinceid": "130000",
            "province": "福建",
            "cityid": "130200",
            "city": "厦门市"
        },
        {
            "bankname": "中国工商银行",
            "name": "中国工商银行股份有限公司厦门杏林湾支行",
            "code": "102393000181",
            "provinceid": "130000",
            "province": "福建",
            "cityid": "130200",
            "city": "厦门市"
        },
        {
            "bankname": "中国工商银行",
            "name": "中国工商银行股份有限公司厦门金融中心支行",
            "code": "102393000253",
            "provinceid": "130000",
            "province": "福建",
            "cityid": "130200",
            "city": "厦门市"
        }
    ]
}

{
    "ok": 0,
    "msg": "页码pages必须为正整数"
}

{
    "ok": 0,
    "msg": "余额不足，且无可用套餐，请充值后重试。"
}

{
    "ok": 0,
    "msg": "接口【银行联行号查询】已停用，暂停调用，请联系管理员。"
}

缺少必要的参数【appid、sendtime、sign】请详看开发文档。
AppID不存在，请联系产品经理进行业务开通。
sendtime不是10位的数字。
时间戳超时，请重新请求。
签名校验失败。
余额不足，请充值后重试。
接口【XXX】已停用，暂停调用，请联系管理员。

curl -X POST "https://leikuang.muzhiyun.com/api/bankcardbase.do" \
  -H "Content-Type: application/json" \
  -d &#039;{"appid":"你的AppID", "sendtime":"<当前时间戳>", "sign":"<按签名算法计算>", "appid":"muzhiyun","sendtime":"1790784000","pages":"1","keys":"厦门 工商" }'

<?php
$appId  = "你的AppID";      // 没有则填 muzhiyun
$appKey = "你的AppKey";
$url    = "https://leikuang.muzhiyun.com/api/bankcardbase.do";

$params = [
    &#039;appid' => 'muzhiyun',
    &#039;sendtime' => '1790784000',
    &#039;pages' => '1',
    &#039;keys' => '厦门 工商',
];
// 以下三项由代码自动补，无需手填
$params["appid"]    = $appId;
$params["sendtime"] = (string)time();
ksort($params);
$src = &#039;';
foreach($params as $k=>$v) $src .= $k.&#039;='.$v.'&';
$src .= &#039;key='.$appKey;
$params["sign"] = strtoupper(md5($src));

$ch = curl_init();
curl_setopt_array($ch, [
    CURLOPT_URL            => $url,
    CURLOPT_POST           => true,
    CURLOPT_HTTPHEADER     => [&#039;Content-Type: application/json'],
    CURLOPT_POSTFIELDS     => json_encode($params, JSON_UNESCAPED_UNICODE),
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_TIMEOUT        => 30,
]);

$resp = curl_exec($ch);
curl_close($ch);
echo $resp;

import time, hashlib, json, urllib.request

APP_ID  = "你的AppID"      # 没有则填 muzhiyun
APP_KEY = "你的AppKey"
URL     = "https://leikuang.muzhiyun.com/api/bankcardbase.do"

params = {
    "appid": "muzhiyun",
    "sendtime": "1790784000",
    "pages": "1",
    "keys": "厦门 工商",
}
params["appid"]    = APP_ID
params["sendtime"] = str(int(time.time()))
params = dict(sorted(params.items()))  # 参数名升序
sign_src = "&".join(f"{k}={v}" for k, v in params.items()) + "&key=" + APP_KEY
params["sign"] = hashlib.md5(sign_src.encode("utf-8")).hexdigest().upper()

req = urllib.request.Request(
    URL,
    data=json.dumps(params).encode("utf-8"),
    headers={"Content-Type": "application/json"},
    method="POST",
)
print(urllib.request.urlopen(req, timeout=30).read().decode("utf-8"))

const url = "https://leikuang.muzhiyun.com/api/bankcardbase.do";
const params = {
  'appid': 'muzhiyun',
  'sendtime': '1790784000',
  'pages': '1',
  'keys': '厦门 工商',
  appid: "你的AppID",
  sendtime: String(Math.floor(Date.now()/1000)),
  // sign: 按上文「签名算法」在前端算 md5(ksort(k=v&…)&key=AppKey) 后填入
};
fetch(url, {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify(params),
}).then(r => r.json()).then(console.log);