/// <summary>
/// Creates a cryptographically strong string
/// </summary>
/// <returns></returns>
public static string Create16CharacterCryptographicallyStrongString(
CryptoStringTypeEnum stringType = CryptoStringTypeEnum.LowercaseAlphaNumeric)
{
return(CreateCryptographicallyStrongString <Sha256Digest>(
stringType)
.Substring(0, 16));
}
/// <summary>
/// Creates a cryptographically strong string with the given digest
/// </summary>
/// <typeparam name="TDigest">Hash type</typeparam>
/// <param name="stringType">Filter to apply to string</param>
/// <returns>A string with only the characters defined by stringType</returns>
private static string CreateCryptographicallyStrongString <TDigest>(
CryptoStringTypeEnum stringType)
where TDigest : IDigest, new()
{
var randomBytes = BitConverter.GetBytes(
new SecureRandom().NextInt());
var digest = new TDigest();
digest.BlockUpdate(
randomBytes,
0,
randomBytes.Length);
var randomDigest = new DigestRandomGenerator(digest);
var cryptoData = new byte[digest.GetDigestSize()];
randomDigest.NextBytes(cryptoData);
var result = Convert.ToBase64String(cryptoData);
switch (stringType)
{
case CryptoStringTypeEnum.Base64AlphaNumeric:
return(result
.Replace('/', '_')
.Replace('+', '-'));
case CryptoStringTypeEnum.LowercaseAlphaNumeric:
return(result
.Replace('/', 'a')
.Replace('+', 'b')
.ToLower());
case CryptoStringTypeEnum.Base64:
default:
return(result);
}
}
public static string Create32CharacterCryptographicallyStrongString(
CryptoStringTypeEnum stringType = CryptoStringTypeEnum.Base64AlphaNumeric)
{
return(CreateCryptographicallyStrongString <Sha256Digest>(
stringType));
}