对于每一次HTTP或者HTTPS协议请求，我们会根据访问中的签名信息验证访问请求者身份。具体由使用AccessKeyID和AccessKeySecret对称加密验证实现。其中AccessKeyID是访问者身份，AccessKeySecret是加密签名字符串和服务器端验证签名字符串的密钥，必须严格保密谨防泄露。

步骤一：指定请求参数

在代码中指定请求参数，参数中需要包含公共请求头和接口必备的参数信息。
说明 请求参数中不允许出现以Signature为key的参数。
示例代码如下： 
String accessKeyId = "testId";
            String accessSecret = "testSecret";
            java.text.SimpleDateFormat df = new java.text.SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
            df.setTimeZone(new java.util.SimpleTimeZone(0, "GMT"));// 这里一定要设置GMT时区
            java.util.Map<String, String> paras = new java.util.HashMap<String, String>();
            // 1. 系统参数
            paras.put("SignatureMethod", "HMAC-SHA1");
            paras.put("SignatureNonce", java.util.UUID.randomUUID().toString());
            paras.put("AccessKeyId", accessKeyId);
            paras.put("SignatureVersion", "1.0");
            paras.put("Timestamp", df.format(new java.util.Date()));
            paras.put("Format", "XML");
            // 2. 业务API参数
            paras.put("Action", "SingleCallByTts");
            paras.put("Version", "2017-05-25");
            paras.put("RegionId", "cn-hangzhou");
            paras.put("CalledShowNumber", "057112345678");
            paras.put("CalledNumber", "13000000000");
            paras.put("TtsParam", "{\"code\":\"1234\",\"product\":\"test\"}");
            paras.put("TtsCode", "TTS_0000000");
            paras.put("OutId", "123");
            // 3. 去除签名关键字Key
            if (paras.containsKey("Signature"))
                paras.remove("Signature");

步骤二：根据参数Key排序（顺序）

参考代码如下： 
java.util.TreeMap<String, String> sortParas = new java.util.TreeMap<String, String>();
sortParas.putAll(paras);

步骤三：构造待签名的请求串

首先介绍下面会用到的特殊URL编码这个是POP特殊的一种规则，即在一般的URLEncode后再增加三种字符替换：加号（+）替换成 %20、星号（*）替换成 %2A、%7E 替换回波浪号（~）参考代码如下： 
public static String specialUrlEncode(String value) throws Exception {
    return java.net.URLEncoder.encode(value, "UTF-8").replace("+", "%20").replace("*", "%2A").replace("%7E", "~");
}
构造待签名的请求串：
  1. 把排序后的参数顺序拼接成如下格式： 
    specialUrlEncode(参数Key) + "=" + specialUrlEncode(参数值)
    参考代码如下： 
    java.util.Iterator<String> it = sortParas.keySet().iterator();
StringBuilder sortQueryStringTmp = new StringBuilder();
while (it.hasNext()) {
    String key = it.next();
    sortQueryStringTmp.append("&").append(specialUrlEncode(key)).append("=").append(specialUrlEncode(paras.get(key)));
}
String sortedQueryString = sortQueryStringTmp.substring(1);// 去除第一个多余的&符号
    打印上面的sortQueryString。结果如下： 
    AccessKeyId%3DtestId&Action%3DSingleCallByTts&CalledNumber%3D13000000000&CalledShowNumber%3D057112345678&Format%3DXML&OutId%3D123&RegionId%3Dcn-hangzhou&SignatureMethod%3DHMAC-SHA1&SignatureNonce%3Df7d2d4ef-6d5f-4da4-86ed-88e001a66abb&SignatureVersion%3D1.0&Timestamp%3D2017-09-28T14%253A31%253A56Z&TtsCode%3DTTS_0000000&TtsParam%3D%257B%2522code%2522%253A%25221234%2522%252C%2522product%2522%253A%2522test%2522%257D&Version%3D2017-05-25
    对应的未URL编码的值（方便用户对比）： 
    AccessKeyId=testId&Action=SingleCallByTts&CalledNumber=13000000000&CalledShowNumber=057112345678&Format=XML&OutId=123&RegionId=cn-hangzhou&SignatureMethod=HMAC-SHA1&SignatureNonce=f7d2d4ef-6d5f-4da4-86ed-88e001a66abb&SignatureVersion=1.0&Timestamp=2017-09-28T14%3A31%3A56Z&TtsCode=TTS_0000000&TtsParam=%7B%22code%22%3A%221234%22%2C%22product%22%3A%22test%22%7D&Version=2017-05-25
  2. 按POP的签名规则拼接成最终的待签名串。
    规则如下： 
    HTTPMethod + “&” + specialUrlEncode(“/”) + ”&” + specialUrlEncode(sortedQueryString)
    参考代码如下： 
    StringBuilder stringToSign = new StringBuilder();
stringToSign.append("GET").append("&");
stringToSign.append(specialUrlEncode("/")).append("&");
stringToSign.append(specialUrlEncode(sortedQueryString));
    完成待签名的请求字符串。打印结果如下： 
    GET&%2F&AccessKeyId%3DtestId&Action%3DSingleCallByTts&CalledNumber%3D13000000000&CalledShowNumber%3D057112345678&Format%3DXML&OutId%3D123&RegionId%3Dcn-hangzhou&SignatureMethod%3DHMAC-SHA1&SignatureNonce%3Df7d2d4ef-6d5f-4da4-86ed-88e001a66abb&SignatureVersion%3D1.0&Timestamp%3D2017-09-28T14%253A31%253A56Z&TtsCode%3DTTS_0000000&TtsParam%3D%257B%2522code%2522%253A%25221234%2522%252C%2522product%2522%253A%2522test%2522%257D&Version%3D2017-05-25

步骤四：签名

签名采用HmacSHA1算法 + Base64，编码采用UTF-8。参考代码如下： 
String sign = sign(accessSecret + "&", stringToSign.toString());
public static String sign(String accessSecret, String stringToSign) throws Exception {
    javax.crypto.Mac mac = javax.crypto.Mac.getInstance("HmacSHA1");
    mac.init(new javax.crypto.spec.SecretKeySpec(accessSecret.getBytes("UTF-8"), "HmacSHA1"));
    byte[] signData = mac.doFinal(stringToSign.getBytes("UTF-8"));
    return new sun.misc.BASE64Encoder().encode(signData);
}
参数说明：
  1. accessSecret：您的AccessKeyId对应的秘钥AccessSecret，特别说明：POP要求需要后面多加一个“&”字符，即accessSecret + “&”。
  2. stringToSign：即第三步生成的待签名请求串。
签名后的结果打印如下： 
aMfgrx8DLS7vLfpeR1c2rrKLr0Q=

步骤五：增加签名结果到请求参数中，发送请求

说明 签名也要做特殊URL编码。 
String Signature = specialUrlEncode(sign);// aMfgrx8DLS7vLfpeR1c2rrKLr0Q%3D
最终完整的GET请求HTTP为： 
http://dyvmsapi.aliyuncs.com/?Signature=aMfgrx8DLS7vLfpeR1c2rrKLr0Q%3D&AccessKeyId=testId&Action=SingleCallByTts&CalledNumber=13000000000&CalledShowNumber=057112345678&Format=XML&OutId=123&RegionId=cn-hangzhou&SignatureMethod=HMAC-SHA1&SignatureNonce=f7d2d4ef-6d5f-4da4-86ed-88e001a66abb&SignatureVersion=1.0&Timestamp=2017-09-28T14%3A31%3A56Z&TtsCode=TTS_0000000&TtsParam=%7B%22code%22%3A%221234%22%2C%22product%22%3A%22test%22%7D&Version=2017-05-25

JAVA示例

完整的Java签名Demo代码： 
public class VmsSignDemo {
     public static void main(String[] args) throws Exception {
            String accessKeyId = "testId";
            String accessSecret = "testSecret";
            java.text.SimpleDateFormat df = new java.text.SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
            df.setTimeZone(new java.util.SimpleTimeZone(0, "GMT"));// 这里一定要设置GMT时区
            java.util.Map<String, String> paras = new java.util.HashMap<String, String>();
            // 1. 系统参数
            paras.put("SignatureMethod", "HMAC-SHA1");
            paras.put("SignatureNonce", java.util.UUID.randomUUID().toString());
            paras.put("AccessKeyId", accessKeyId);
            paras.put("SignatureVersion", "1.0");
            paras.put("Timestamp", df.format(new java.util.Date()));
            paras.put("Format", "XML");
            // 2. 业务API参数
            paras.put("Action", "SingleCallByTts");
            paras.put("Version", "2017-05-25");
            paras.put("RegionId", "cn-hangzhou");
            paras.put("CalledShowNumber", "057112345678");
            paras.put("CalledNumber", "13000000000");
            paras.put("TtsParam", "{\"code\":\"1234\",\"product\":\"test\"}");
            paras.put("TtsCode", "TTS_0000000");
            paras.put("OutId", "123");
            // 3. 去除签名关键字Key
            if (paras.containsKey("Signature"))
                paras.remove("Signature");
            // 4. 参数KEY排序
            java.util.TreeMap<String, String> sortParas = new java.util.TreeMap<String, String>();
            sortParas.putAll(paras);
            // 5. 构造待签名的字符串
            java.util.Iterator<String> it = sortParas.keySet().iterator();
            StringBuilder sortQueryStringTmp = new StringBuilder();
            while (it.hasNext()) {
                String key = it.next();
                sortQueryStringTmp.append("&").append(specialUrlEncode(key)).append("=").append(specialUrlEncode(paras.get(key)));
            }
            String sortedQueryString = sortQueryStringTmp.substring(1);// 去除第一个多余的&符号
            StringBuilder stringToSign = new StringBuilder();
            stringToSign.append("GET").append("&");
            stringToSign.append(specialUrlEncode("/")).append("&");
            stringToSign.append(specialUrlEncode(sortedQueryString));
            String sign = sign(accessSecret + "&", stringToSign.toString());
            // 6. 签名最后也要做特殊URL编码
            String signature = specialUrlEncode(sign);
            System.out.println(paras.get("SignatureNonce"));
            System.out.println("\r\n=========\r\n");
            System.out.println(paras.get("Timestamp"));
            System.out.println("\r\n=========\r\n");
            System.out.println(sortedQueryString);
            System.out.println("\r\n=========\r\n");
            System.out.println(stringToSign.toString());
            System.out.println("\r\n=========\r\n");
            System.out.println(sign);
            System.out.println("\r\n=========\r\n");
            System.out.println(signature);
            System.out.println("\r\n=========\r\n");
            // 最终打印出合法GET请求的URL
            System.out.println("http://dyvmsapi.aliyuncs.com/?Signature=" + signature + sortQueryStringTmp);
        }
        public static String specialUrlEncode(String value) throws Exception {
            return java.net.URLEncoder.encode(value, "UTF-8").replace("+", "%20").replace("*", "%2A").replace("%7E", "~");
        }
        public static String sign(String accessSecret, String stringToSign) throws Exception {
            javax.crypto.Mac mac = javax.crypto.Mac.getInstance("HmacSHA1");
            mac.init(new javax.crypto.spec.SecretKeySpec(accessSecret.getBytes("UTF-8"), "HmacSHA1"));
            byte[] signData = mac.doFinal(stringToSign.getBytes("UTF-8"));
            return new sun.misc.BASE64Encoder().encode(signData);
        }
}
`