<%@Import Namespace="System.Security.Cryptography" %>

<img src="http://mqr.kr/qr/?t=HelloWorld&amp;r=10&amp;sign=<%=CalculateSign("t=HelloWorld&r=10", "00112233445566778899aabbccddeeff")%>"/>

<script runat="server">
string CalculateSign(string text, string key)
{
        byte[] keyBytes = new byte[key.Length / 2];
        for (int i = 0; i < keyBytes.Length; i++)
                keyBytes[i] = Convert.ToByte(key.Substring(i * 2, 2), 16);
        byte[] textBytes = Encoding.ASCII.GetBytes(text);
        byte[] sign;
        using (HMACSHA256 hmac = new HMACSHA256(keyBytes))
                sign = hmac.ComputeHash(textBytes);
        return string.Join(string.Empty, sign.Select(b => b.ToString("x2")));
}
</script>

예제 2)  현재 날짜 / 시간으로 QR 코드를 생성을위한 .Net 코드 샘플

<%@Import Namespace="System.Security.Cryptography" %>

<%
	string text = DateTime.Now.ToString(@"yyyy\.MM\.dd HH\:mm\:ss");
	string query = string.Format("t={0}&r=10&j=1",
		HttpUtility.HtmlEncode(text));
%>
<img src="http://mqr.kr/qr/?<%:query%>&amp;sign=<%:CalculateSign(query, "00112233445566778899aabbccddeeff")%>"/>

<script runat="server">
string CalculateSign(string text, string key)
{
	byte[] keyBytes = new byte[key.Length / 2];
	for (int i = 0; i < keyBytes.Length; i++)
		keyBytes[i] = Convert.ToByte(key.Substring(i * 2, 2), 16);
	byte[] textBytes = Encoding.ASCII.GetBytes(text);
	byte[] sign;
	using (HMACSHA256 hmac = new HMACSHA256(keyBytes))
		sign = hmac.ComputeHash(textBytes);
	return string.Join(string.Empty, sign.Select(b => b.ToString("x2")));
}
</script>

예제 3)  홈페이지 현재 URL 정보를 담은 QR코드 자동 생성을위한 .Net 코드 샘플

<%@Import Namespace="System.Security.Cryptography" %>

<%
        string text = Request.Url.ToString();
        string query = string.Format("t={0}&r=10&j=1",
                HttpUtility.HtmlEncode(text));
%>
<img src="http://mqr.kr/qr/?<%:query%>&amp;sign=<%:CalculateSign(query, "00112233445566778899aabbccddeeff")%>"/>

<script runat="server">
string CalculateSign(string text, string key)
{
        byte[] keyBytes = new byte[key.Length / 2];
        for (int i = 0; i < keyBytes.Length; i++)
                keyBytes[i] = Convert.ToByte(key.Substring(i * 2, 2), 16);
        byte[] textBytes = Encoding.ASCII.GetBytes(text);
        byte[] sign;
        using (HMACSHA256 hmac = new HMACSHA256(keyBytes))
                sign = hmac.ComputeHash(textBytes);
        return string.Join(string.Empty, sign.Select(b => b.ToString("x2")));
}
</script>