/// <summary>
/// Checks whether a passed in password has been pwned previously.
/// Determines if the password is safe (never been pwned),
/// at risk (pwned 1-10 times), or unnacceptable(pwned > 10 times).
/// </summary>
/// <param name="password">A password</param>
/// <returns>PasswordStatus which conatins a number and message that determines the security risk.
/// 0 - no risk. 1 - small risk/recommend change password. 2 - risky/password not accepted
/// -1 - an error occurred in the http request </returns>
public async Task <PasswordStatus> IsPasswordSafe(string password)
{
if (password.Length < 12)
{
PasswordStatus status = new PasswordStatus(-2, "That's not a valid password!");
return(status);
}
else
{
//Password converted to bytes and hashed.
string stringHash = sHash.StringHash(password);
//Gets the first five characters of the hashed password (prefix)
string prefix = stringHash.Substring(0, 5);
//Calls FindPassword to see all pwned passwords that have the same prefix
//checkPwned is Task<String>
var checkPwned = await pvs.FindPassword(prefix);
//restOfHash is part of password hash that is not the prefix
string restOfHash = stringHash.Substring(5, stringHash.Length - 5);
//Check if password has been pwned and if its usable. Get object with int representing status & a message.
//Status number and message are stored in PasswordStatus object
PasswordStatus status = checkStatus.StatusOfPassword(checkPwned, restOfHash);
return(status);
}
}