// Updates the password by iterating the MD5 hashes, like the previous problem. But, now the 6th character tells you the
// digit of the password to update with the 7th character.
public string DetermineSecurityDoorPasswordPartTwo(string input)
{
string result = "--------";
long counter = -1;
MD5 md5Hash = MD5.Create();
// Loop until we have our full password, i.e. one that no longer has -'s in it
do
{
++counter;
string hashInput = input + counter;
string resultHash = Md5Utility.GetMd5Hash(md5Hash, hashInput);
// Check to see if the resultHash is valid - i.e. starts with 5 zeros
if (resultHash.Substring(0, 5) == "00000")
{
// Then add the sixth character to accumulating password
result = HandleResultUpdate(result, resultHash);
}
} while (result.IndexOf('-') != -1);
return(result);
}
// Determine the security door password by iterating through MD5 hashs looking for hashes that begin with "00000"
// Then use the next character to collect the password
public string DetermineSecurityDoorPassword(string input)
{
string result = "";
long counter = -1;
MD5 md5Hash = MD5.Create();
// Loop until we have our full password of 8 characters
do
{
++counter;
string hashInput = input + counter;
string resultHash = Md5Utility.GetMd5Hash(md5Hash, hashInput);
// Check to see if the resultHash is valid - i.e. starts with 5 zeros
if (resultHash.Substring(0, 5) == "00000")
{
// Then add the sixth character to accumulating password
result += resultHash.Substring(5, 1);
}
} while (result.Length < 8);
return(result);
}
public string CreateMd5Hash(MD5 md5Hash, long counter, string salt)
{
string combined = $"{salt}{counter}";
string hash = Md5Utility.GetMd5Hash(md5Hash, combined);
return(hash);
}
public string CreateStretchedMd5Hash(MD5 md5Hash, long counter, string salt)
{
string iterativeHash = $"{salt}{counter}";
for (int i = 0; i < 2017; i++)
{
string hash = Md5Utility.GetMd5Hash(md5Hash, iterativeHash);
iterativeHash = hash;
}
return(iterativeHash);
}
// Creates a series of characters that follow compass - [0] = North, [1] = South, [2] = Left, [3] = East
public List <char> OpenDoorsForRoom(string passcode, MD5 md5Hash)
{
List <char> result = new List <char>();
string hash = Md5Utility.GetMd5Hash(md5Hash, passcode);
List <char> dirs = hash.Substring(0, 4).ToList <char>();
for (int i = 0; i < 4; i++)
{
char dir = dirs[i];
if (VALID_CHARS.Contains(dir))
{
result.Add('O');
}
else
{
result.Add('C');
}
}
return(result);
}