public string CreateMac(string header, DateTime timestamp, string nonce, string verb, Uri uri, string contentHash, string ext, string app, byte[] key)
{
// Escape the ext string.
if (!string.IsNullOrEmpty(ext))
{
ext = ext.Replace("\\", "\\\\").Replace("\n", "\\n");
}
// Create our version of the hash.
var hashContent = new List<string>
{
"hawk.1." + header,
timestamp.ToSecondTime().ToString(CultureInfo.InvariantCulture),
nonce,
verb.ToUpper(),
uri.PathAndQuery,
uri.Host,
uri.Port.ToString(CultureInfo.InvariantCulture),
contentHash,
ext
};
// If needed, add the App parameter.
if (!string.IsNullOrEmpty(app))
{
hashContent.Add(app);
hashContent.Add(string.Empty);
}
// Trailing breaks.
hashContent.Add(string.Empty);
var hashContentStr = string.Join("\n", hashContent);
// Hash it using the HMAC256 algorithm.
using (var hmac = new HMACSHA256(key))
{
var hashValue = hmac.ComputeHash(Encoding.UTF8.GetBytes(hashContentStr));
return Convert.ToBase64String(hashValue);
}
}
public string CreateStaleTimestampMac(DateTime timestamp, byte[] key)
{
// Create the unashed version of the mac.
var hashContent = new List<string>
{
"hawk.1.ts",
timestamp.ToSecondTime().ToString(CultureInfo.InvariantCulture)
};
var hashContentStr = string.Join("\n", hashContent);
// Hash it using the HMAC256 algorithm.
using (var hmac = new HMACSHA256(key))
{
var hashValue = hmac.ComputeHash(Encoding.UTF8.GetBytes(hashContentStr));
return Convert.ToBase64String(hashValue);
}
}
public string CreateBewit(DateTime expiresAt, Uri uri, string ext, string bewitId, byte[] key)
{
// Create the mac hash.
var mac = this.CreateMac("bewit", expiresAt, null, "GET", uri, null, ext, null, key);
// Use it to create the bewit.
var bewit = string.Format(CultureInfo.InvariantCulture, "{0}\\{1}\\{2}\\{3}", bewitId, expiresAt.ToSecondTime(), mac, ext);
return Convert.ToBase64String(Encoding.UTF8.GetBytes(bewit)).TrimEnd('=');
}
