CODEWITHSUNDEEP
c#cryptojs
CarComp
CarComp

Reputation: 2018

What is the C# equivalent of `CryptoJS.HmacSHA256`

I have some code written in javascript that is as follows which is working properly:

var generateSignature = function(apiKey, apiSecret, meetingNumber, role) {

    // Prevent time sync issue between client signature generation and zoom 
    var timestamp = new Date().getTime() - 30000;
    var msg = btoa(apiKey + meetingNumber + timestamp + role);
    var hash = window.CryptoJS.HmacSHA256(msg, apiSecret);
    var hashedBaseItems = CryptoJS.enc.Base64.stringify(hash);
    var encodableString = apiKey + "." + meetingNumber + "." + timestamp + "." + role + "." + hashedBaseItems;
    signature = btoa(encodableString);
    return signature;
}

I'm trying to convert them to C# equivalents, but with mixed results. Here is what I have so far:

    public string GenerateSignature(int role, long meetingNumber)
    {
        // Prevent time sync issue between client signature generation and zoom 
        long timeStamp = this.getLinuxEpochTimestamp() - 30000;

        string baseItems = _plusConfig.Value.ZoomApiKey + meetingNumber + timeStamp + role;
        string msg = this.jsbtoaEquivalentEncoding(baseItems);
        string hashedBaseItems = generateHash(msg, _plusConfig.Value.ZoomApiSecret);
        string dottedItems = _plusConfig.Value.ZoomApiKey + "." + meetingNumber + "." + timeStamp + "." + role + "." + hashedBaseItems;

        return this.jsbtoaEquivalentEncoding(dottedItems);
    }

    private long getLinuxEpochTimestamp()
    {
        return (long) DateTime.UtcNow.Subtract(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalMilliseconds;
    }

    private string jsbtoaEquivalentEncoding(string toEncode)
    {
        byte[] bytes = Encoding.GetEncoding(28591).GetBytes(toEncode);
        string toReturn = System.Convert.ToBase64String(bytes);
        return toReturn;
    }

    private static string generateHash(string str, string cypherkey)
    {
        // based on CryptoJS.enc.Base64.parse
        byte[] keyBytes = Convert.FromBase64String(cypherkey);

        using (HMACSHA256 hmacsha256 = new HMACSHA256(keyBytes))
        {
            byte[] hashmessage = hmacsha256.ComputeHash(System.Text.Encoding.UTF8.GetBytes(str));
            return Convert.ToBase64String(hashmessage);
        }
    }

What am I doing wrong where the generateHash function is returning something completely different than the CryptoJS.HmacSHA256 function?

Upvotes: 1

Views: 2181

Answers (1)

R-nold
R-nold

Reputation: 242

private static string generateHash(string str, string cypherkey)
{
    var encoding = new System.Text.ASCIIEncoding();

    var messageBytes = encoding.GetBytes(str);
    var keyBytes = encoding.GetBytes(cypherkey);

    using var hmacsha256 = new HMACSHA256(keyBytes);
    var hashmessage = hmacsha256.ComputeHash(messageBytes);
    return Convert.ToBase64String(hashmessage);
}

Should solve the issue.

Upvotes: 2

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