/// <summary>
/// Finalizes the hash computation after the last data is processed by the cryptographic stream object.
/// </summary>
/// <returns>
/// The computed hash code.
/// </returns>
protected override byte[] HashFinal()
{
// finalize the original hash
var hashValue = _hashProvider.ComputeHash(new byte[0]);
// write the outer padding
_hashProvider.TransformBlock(_outerPadding, 0, BlockSize, _outerPadding, 0);
// write the inner hash and finalize the hash
_hashProvider.TransformFinalBlock(hashValue, 0, hashValue.Length);
var hash = _hashProvider.Hash;
return(GetTruncatedHash(hash));
}
public byte[] ComputeHash(byte[] data, byte[] salt)
{
byte[] saltedData = Concatenate(data, salt);
byte[] hashBytes = hashProvider.ComputeHash(saltedData);
return(hashBytes);
}
public bool IsValid(string userName, string password)
{
if (string.IsNullOrEmpty(userName) || string.IsNullOrEmpty(password))
{
return(false);
}
var passwordHash = HashProvider.ComputeHash(password);
return(string.Equals(userName, _configuration.UserName) &&
string.Equals(passwordHash, _configuration.Password));
}
/// <summary>
/// Hashes and encodes the signature for encryption. Uses the DER (Distinguished Encoding Rules)
/// and the SHA256 hash provider for encoding generation.
/// </summary>
/// <param name="dataBytes">Data to be signed</param>
/// <param name="params">RSA Parameters used for signature calculation</param>
/// <returns>Computed signature (pre-encryption)</returns>
public byte[] EncodeSignature(byte[] dataBytes, RSAParameters @params)
{
//Set the intended message length (key length)
int emLen = @params.N.Length;
//Compute the hash of the data
byte[] H = m_hashProvider.ComputeHash(dataBytes);
//Get the digest encoding information for the hash being used.
byte[] bytDigestEncoding = DigestEncoding.SHA256();
//Create the hashed message including the digest info
byte[] T = new byte[(bytDigestEncoding.Length + m_hLen)];
bytDigestEncoding.CopyTo(T, 0);
H.CopyTo(T, bytDigestEncoding.Length);
H = null;
bytDigestEncoding = null;
if (emLen < T.Length + 11)
{
throw new CryptographicException("Message too short.");
}
//Create the padding string, octet string of 0xff
byte[] PS = new byte[(emLen - T.Length - 3)];
for (int i = 0; i <= PS.Length - 1; i++)
{
PS[i] = 0xff;
}
byte[] result = new byte[emLen];
//Add the leading identifier bytes
result[0] = 0x00;
result[1] = 0x01;
//Copy the padding string to the result
PS.CopyTo(result, 2);
//Add the separator byte
result[PS.Length + 2] = 0x00;
//Copy the digest info
T.CopyTo(result, PS.Length + 3);
PS = null;
T = null;
return(result);
}
public async Task <User> AuthenticateAsync(LoginInfo info)
{
using (var ctx = dbFactory.NewUserDbContext()) {
var user = await ctx.Users.FirstOrDefaultAsync(x => x.Username == info.Username);
var pwSalt = (info?.Password ?? string.Empty) + (user?.Salt ?? string.Empty);
var pwHash = hashProvider.ComputeHash(pwSalt);
if (user?.Password != pwHash)
{
user = null;
}
return(user);
}
}
/// <summary>
/// Mask generation function.
/// </summary>
/// <param name="seed">Seed</param>
/// <param name="maskLen">Length of generated mask</param>
/// <param name="hashLength">Length of the hash produced by the supplied hash provider</param>
/// <param name="hashProvider">Hash provider to use in mask generation</param>
/// <returns>Generated mask of specified length</returns>
static internal byte[] OAEPMGF(byte[] seed, int maskLen, int hashLength, IHashProvider hashProvider)
{
byte[] result = new byte[maskLen];
//Determine how many interations we have to do. We'll be appending
//m_hLen (hash length) bytes for every iteration, so the size of the generated byte array
//will be m_hLen * iNum (number of iterations).
int iNum = (int)Math.Floor(maskLen / hashLength) + 1;
//Mask that will be truncated to create the final
//resulting mask returned by this function.
byte[] bytLongMask = new byte[(iNum * hashLength)];
byte[] bytAppend = new byte[4];
byte[] bytTmp = null;
int iPadLen = 0;
byte[] bytSeedHash = new byte[hashLength];
//Padded pseudorandom seed to be hashed.
byte[] bytPadSeed = new byte[(seed.Length + 4)];
seed.CopyTo(bytPadSeed, 0);
for (int i = 0; i <= iNum - 1; i++)
{
//Convert the iterator to an Octet String byte array
bytTmp = Mathematics.I2OSP(i, 4);
//Calculate the needed padding zeros, and add
//them to the resulting Array. Result must be 4 bytes long.
iPadLen = bytAppend.Length - bytTmp.Length;
bytTmp.CopyTo(bytAppend, 0);
//Hash the pseudorandom padded seed and append it to the
//long version of the mask.
bytAppend.CopyTo(bytPadSeed, seed.Length);
bytSeedHash = hashProvider.ComputeHash(bytPadSeed);
bytSeedHash.CopyTo(bytLongMask, i * hashLength);
}
//Copy the first maskLen bytes of bytLongMask to the result
//and return the result.
Array.Copy(bytLongMask, result, maskLen);
return(result);
}
public void ResetCertificatePassword(Guid id, ClaimsPrincipal user)
{
Certificate cert = certificateRepository.Get <Certificate>(id);
if (!authorizationLogic.CanViewPrivateKey(cert, user))
{
audit.LogSecurityAuditFailure(user, cert, EventCategory.CertificatePasswordReset);
throw new UnauthorizedAccessException();
}
if (!hashProvider.ValidateData(cert.Content, cert.ContentDigest))
{
throw new InvalidOperationException("Certificate data is corrupt");
}
if (!cert.HasPrivateKey || cert.CertificateStorageFormat != CertificateStorageFormat.Pfx)
{
throw new ObjectNotInCorrectStateException("Certificate does not have a private key");
}
audit.LogSecurityAuditSuccess(user, cert, EventCategory.CertificatePasswordReset);
byte[] certBytes = cert.Content;
X509Certificate2 x509 = new X509Certificate2();
x509.Import(certBytes, cipher.Decrypt(cert.PfxPassword, cert.PasswordNonce), X509KeyStorageFlags.Exportable);
string nonce = keygen.NewSecretBase64(16);
string password = keygen.NewSecret(64);
byte[] newBytes = x509.Export(X509ContentType.Pfx, password);
cert.ContentDigest = hashProvider.ComputeHash(newBytes);
cert.Content = newBytes;
cert.PfxPassword = cipher.Encrypt(password, nonce);
cert.PasswordNonce = nonce;
certificateRepository.Update <Certificate>(cert);
}
/// <summary>
/// Mask generation function.
/// </summary>
/// <param name="seed">Seed</param>
/// <param name="maskLen">Length of generated mask</param>
/// <param name="hashLength">Length of the hash produced by the supplied hash provider</param>
/// <param name="hashProvider">Hash provider to use in mask generation</param>
/// <returns>Generated mask of specified length</returns>
static internal byte[] OAEPMGF(byte[] seed, int maskLen, int hashLength, IHashProvider hashProvider)
{
byte[] result = new byte[maskLen];
//Determine how many interations we have to do. We'll be appending
//m_hLen (hash length) bytes for every iteration, so the size of the generated byte array
//will be m_hLen * iNum (number of iterations).
int iNum = (int)Math.Floor(maskLen / hashLength) + 1;
//Mask that will be truncated to create the final
//resulting mask returned by this function.
byte[] bytLongMask = new byte[(iNum * hashLength)];
byte[] bytAppend = new byte[4];
byte[] bytTmp = null;
int iPadLen = 0;
byte[] bytSeedHash = new byte[hashLength];
//Padded pseudorandom seed to be hashed.
byte[] bytPadSeed = new byte[(seed.Length + 4)];
seed.CopyTo(bytPadSeed, 0);
for (int i = 0; i <= iNum - 1; i++)
{
//Convert the iterator to an Octet String byte array
bytTmp = Mathematics.I2OSP(i, 4);
//Calculate the needed padding zeros, and add
//them to the resulting Array. Result must be 4 bytes long.
iPadLen = bytAppend.Length - bytTmp.Length;
bytTmp.CopyTo(bytAppend, 0);
//Hash the pseudorandom padded seed and append it to the
//long version of the mask.
bytAppend.CopyTo(bytPadSeed, seed.Length);
bytSeedHash = hashProvider.ComputeHash(bytPadSeed);
bytSeedHash.CopyTo(bytLongMask, i * hashLength);
}
//Copy the first maskLen bytes of bytLongMask to the result
//and return the result.
Array.Copy(bytLongMask, result, maskLen);
return result;
}
/// <summary>
/// Adds padding to the input data and returns the padded data.
/// </summary>
/// <param name="dataBytes">Data to be padded prior to encryption</param>
/// <param name="params">RSA Parameters used for padding computation</param>
/// <returns>Padded message</returns>
public byte[] EncodeMessage(byte[] dataBytes, RSAParameters @params)
{
//Iterator
int i = 0;
//Get the size of the data to be encrypted
m_mLen = dataBytes.Length;
//Get the size of the public modulus (will serve as max length for cipher text)
m_k = @params.N.Length;
if (m_mLen > GetMaxMessageLength(@params))
{
throw new CryptographicException("Bad Data.");
}
//Generate the random octet seed (same length as hash)
BigInteger biSeed = new BigInteger();
biSeed.genRandomBits(m_hLen * 8, new Random());
byte[] bytSeed = biSeed.getBytesRaw();
//Make sure all of the bytes are greater than 0.
for (i = 0; i <= bytSeed.Length - 1; i++)
{
if (bytSeed[i] == 0x00)
{
//Replacing with the prime byte 17, no real reason...just picked at random.
bytSeed[i] = 0x17;
}
}
//Mask the seed with MFG Function(SHA1 Hash)
//This is the mask to be XOR'd with the DataBlock below.
byte[] dbMask = Mathematics.OAEPMGF(bytSeed, m_k - m_hLen - 1, m_hLen, m_hashProvider);
//Compute the length needed for PS (zero padding) and
//fill a byte array to the computed length
int psLen = GetMaxMessageLength(@params) - m_mLen;
//Generate the SHA1 hash of an empty L (Label). Label is not used for this
//application of padding in the RSA specification.
byte[] lHash = m_hashProvider.ComputeHash(System.Text.Encoding.UTF8.GetBytes(string.Empty.ToCharArray()));
//Create a dataBlock which will later be masked. The
//data block includes the concatenated hash(L), PS,
//a 0x01 byte, and the message.
int dbLen = m_hLen + psLen + 1 + m_mLen;
byte[] dataBlock = new byte[dbLen];
int cPos = 0;
//Current position
//Add the L Hash to the data blcok
for (i = 0; i <= lHash.Length - 1; i++)
{
dataBlock[cPos] = lHash[i];
cPos += 1;
}
//Add the zero padding
for (i = 0; i <= psLen - 1; i++)
{
dataBlock[cPos] = 0x00;
cPos += 1;
}
//Add the 0x01 byte
dataBlock[cPos] = 0x01;
cPos += 1;
//Add the message
for (i = 0; i <= dataBytes.Length - 1; i++)
{
dataBlock[cPos] = dataBytes[i];
cPos += 1;
}
//Create the masked data block.
byte[] maskedDB = Mathematics.BitwiseXOR(dbMask, dataBlock);
//Create the seed mask
byte[] seedMask = Mathematics.OAEPMGF(maskedDB, m_hLen, m_hLen, m_hashProvider);
//Create the masked seed
byte[] maskedSeed = Mathematics.BitwiseXOR(bytSeed, seedMask);
//Create the resulting cipher - starting with a 0 byte.
byte[] result = new byte[@params.N.Length];
result[0] = 0x00;
//Add the masked seed
maskedSeed.CopyTo(result, 1);
//Add the masked data block
maskedDB.CopyTo(result, maskedSeed.Length + 1);
return(result);
}
/// <summary>
/// Initializes a new instance of the <see cref="MerkleNode"/> class.
/// </summary>
/// <param name="hashProvider">The hash provider.</param>
/// <param name="left">The left child node.</param>
/// <param name="right">The right child node.</param>
internal MerkleNode(IHashProvider hashProvider, MerkleNodeBase left, MerkleNodeBase right)
{
this.right = right;
this.left = left;
this.nodeHash = hashProvider.ComputeHash(left.Hash.GetHashBytes().Concat(right.Hash.GetHashBytes()).ToArray());
}
public IEnumerable <string> GetHashes(IHashProvider DefaultHashProvider)
{
//TODO: This class should handle caching of the data.
//._content is used for performance reasons (as we do not need to copy the byte array).
return(from file in ContainedFiles select DefaultHashProvider.ComputeHash(file.GetContent()));
}
