/// <summary>
/// <para>Do final processing and get the hash value.
/// Note: Digest is not reset after calling DoFinal.
/// <see cref="Reset()"/> must be called before a new hash can be generated.</para>
/// </summary>
///
/// <param name="Output">The Hash value container</param>
/// <param name="OutOffset">The starting offset within the Output array</param>
///
/// <returns>Size of Hash value</returns>
///
/// <exception cref="CryptoHashException">Thrown if Output array is too small</exception>
public int DoFinal(byte[] Output, int OutOffset)
{
if (Output.Length - OutOffset < DigestSize)
{
throw new CryptoHashException("Skein256:DoFinal", "The Output buffer is too short!", new ArgumentOutOfRangeException());
}
// pad left over space in input buffer with zeros
for (int i = m_bytesFilled; i < m_inputBuffer.Length; i++)
{
m_inputBuffer[i] = 0;
}
// copy to cipher input buffer
for (int i = 0; i < STATE_WORDS; i++)
{
m_cipherInput[i] = BytesToUInt64(m_inputBuffer, i * 8);
}
// do final message block
m_ubiParameters.IsFinalBlock = true;
ProcessBlock(m_bytesFilled);
// clear cipher input
Array.Clear(m_cipherInput, 0, m_cipherInput.Length);
// do output block counter mode output
byte[] hash = new byte[m_outputBytes];
ulong[] oldState = new ulong[STATE_WORDS];
// save old state
Array.Copy(m_digestState, oldState, m_digestState.Length);
for (int i = 0; i < m_outputBytes; i += STATE_BYTES)
{
m_ubiParameters.StartNewBlockType(UbiType.Out);
m_ubiParameters.IsFinalBlock = true;
ProcessBlock(8);
// output a chunk of the hash
int outputSize = m_outputBytes - i;
if (outputSize > STATE_BYTES)
{
outputSize = STATE_BYTES;
}
PutBytes(m_digestState, hash, i, outputSize);
// restore old state
Array.Copy(oldState, m_digestState, oldState.Length);
// increment counter
m_cipherInput[0]++;
}
Buffer.BlockCopy(hash, 0, Output, OutOffset, hash.Length);
return(hash.Length);
}
/// <remarks>
/// Default generation function
/// </remarks>
private void GenerateConfiguration()
{
Threefish512 cipher = new Threefish512();
UbiTweak tweak = new UbiTweak();
// initialize the tweak value
tweak.StartNewBlockType(UbiType.Config);
tweak.IsFinalBlock = true;
tweak.BitsProcessed = 32;
cipher.SetTweak(tweak.Tweak);
cipher.Encrypt(m_configString, m_configValue);
m_configValue[0] ^= m_configString[0];
m_configValue[1] ^= m_configString[1];
m_configValue[2] ^= m_configString[2];
}
/// <remarks>
/// Default generation function
/// </remarks>
private void GenerateConfiguration()
{
var cipher = new Threefish256();
var tweak = new UbiTweak();
// Initialize the tweak value
tweak.StartNewBlockType(UbiType.Config);
tweak.IsFinalBlock = true;
tweak.BitsProcessed = 32;
cipher.SetTweak(tweak.Tweak);
cipher.Encrypt(ConfigString, ConfigValue);
ConfigValue[0] ^= ConfigString[0];
ConfigValue[1] ^= ConfigString[1];
ConfigValue[2] ^= ConfigString[2];
}
/// <remarks>
/// Default generation function
/// </remarks>
private void GenerateConfiguration()
{
var cipher = new Threefish512();
var tweak = new UbiTweak();
// Initialize the tweak value
tweak.StartNewBlockType(UbiType.Config);
tweak.IsFinalBlock = true;
tweak.BitsProcessed = 32;
cipher.SetTweak(tweak.Tweak);
cipher.Encrypt(ConfigString, ConfigValue);
ConfigValue[0] ^= ConfigString[0];
ConfigValue[1] ^= ConfigString[1];
ConfigValue[2] ^= ConfigString[2];
}