private byte[] HashPassword(string password, RandomNumberGenerator rng, Pbkdf2Provider pbkdf2Provider)
{
return(HashPasswordV3(password,
iterCount: _pbkdf2IterCount,
saltSize: _saltSize,
numBytesRequested: _pbkdf2SubkeyLength,
rng: rng,
pbkdf2Provider: pbkdf2Provider));
}
private static byte[] HashPasswordV3(string password, int iterCount, int saltSize, int numBytesRequested, RandomNumberGenerator rng, Pbkdf2Provider pbkdf2Provider)
{
// Produce a version 2 (see comment above) text hash.
byte[] salt = new byte[_saltSize];
rng.GetBytes(salt);
byte[] subkey = pbkdf2Provider.DeriveKey(password, salt, iterCount, numBytesRequested);
var outputBytes = new byte[13 + salt.Length + subkey.Length];
outputBytes[0] = 0x01; // format marker
WriteNetworkByteOrder(outputBytes, 1, (uint)KeyDerivationPrf.HMACSHA256);
WriteNetworkByteOrder(outputBytes, 5, (uint)iterCount);
WriteNetworkByteOrder(outputBytes, 9, (uint)saltSize);
Buffer.BlockCopy(salt, 0, outputBytes, 13, salt.Length);
Buffer.BlockCopy(subkey, 0, outputBytes, 13 + saltSize, subkey.Length);
return(outputBytes);
}
private const int _saltSize = 128 / 8; // 128 bits
/// <summary>
/// Creates a new instance of <see cref="PasswordHasher{TUser}"/>.
/// </summary>
/// <param name="optionsAccessor">The options for this instance.</param>
public SimplePasswordHasher()
{
_rng = RandomNumberGenerator.Create();
_pbkdf2Provider = new Pbkdf2Provider();
}
private static bool VerifyHashedPassword(byte[] hashedPassword, string password, Pbkdf2Provider pbkdf2Provider)
{
try
{
// Read header information
//KeyDerivationPrf prf = (KeyDerivationPrf)ReadNetworkByteOrder(hashedPassword, 1);
var iterCount = (int)ReadNetworkByteOrder(hashedPassword, 5);
int saltLength = (int)ReadNetworkByteOrder(hashedPassword, 9);
// Lower iteration count will be denied.
if (iterCount < _pbkdf2IterCount)
{
return(false);
}
// Read the salt: must be >= 128 bits
if (saltLength < 128 / 8)
{
return(false);
}
byte[] salt = new byte[saltLength];
Buffer.BlockCopy(hashedPassword, 13, salt, 0, salt.Length);
// Read the subkey (the rest of the payload): must be >= 128 bits
int subkeyLength = hashedPassword.Length - 13 - salt.Length;
if (subkeyLength < 128 / 8)
{
return(false);
}
byte[] expectedSubkey = new byte[subkeyLength];
Buffer.BlockCopy(hashedPassword, 13 + salt.Length, expectedSubkey, 0, expectedSubkey.Length);
// Hash the incoming password and verify it
byte[] actualSubkey = pbkdf2Provider.DeriveKey(password, salt, iterCount, subkeyLength);
return(ByteArraysEqual(actualSubkey, expectedSubkey));
}
catch
{
// This should never occur except in the case of a malformed payload, where
// we might go off the end of the array. Regardless, a malformed payload
// implies verification failed.
return(false);
}
}