/// <summary>
/// Derives a secret key of any size from a password and a salt.
/// </summary>
/// <param name="password">The password.</param>
/// <param name="salt">The salt.</param>
/// <param name="opsLimit">Represents a maximum amount of computations to perform.</param>
/// <param name="memLimit">Is the maximum amount of RAM that the function will use, in bytes.</param>
/// <param name="outputLength">The length of the computed output array.</param>
/// <returns>Returns a byte array of the given size.</returns>
/// <exception cref="ArgumentNullException"></exception>
/// <exception cref="ArgumentOutOfRangeException"></exception>
/// <exception cref="SaltOutOfRangeException"></exception>
/// <exception cref="OutOfMemoryException"></exception>
public static byte[] ScryptHashBinary(byte[] password, byte[] salt, long opsLimit, int memLimit,
long outputLength = SCRYPT_SALSA208_SHA256_SALTBYTES)
{
if (password == null)
{
throw new ArgumentNullException("password", "Password cannot be null");
}
if (salt == null)
{
throw new ArgumentNullException("salt", "Salt cannot be null");
}
if (salt.Length != SCRYPT_SALSA208_SHA256_SALTBYTES)
{
throw new SaltOutOfRangeException(string.Format("Salt must be {0} bytes in length.",
SCRYPT_SALSA208_SHA256_SALTBYTES));
}
if (opsLimit <= 0)
{
throw new ArgumentOutOfRangeException("opsLimit", "opsLimit cannot be zero or negative");
}
if (memLimit <= 0)
{
throw new ArgumentOutOfRangeException("memLimit", "memLimit cannot be zero or negative");
}
if (outputLength <= 0)
{
throw new ArgumentOutOfRangeException("outputLength", "OutputLength cannot be zero or negative");
}
var buffer = new byte[outputLength];
var ret = SodiumLibrary.crypto_pwhash_scryptsalsa208sha256(buffer, buffer.Length, password,
password.LongLength, salt, opsLimit, memLimit);
if (ret != 0)
{
throw new OutOfMemoryException(
"Internal error, hash failed (usually because the operating system refused to allocate the amount of requested memory).");
}
return(buffer);
}
