peass-ng/PEASS-ng · error · ArgumentException

Invalid parameter passed to Threefish init -

Error message

Invalid parameter passed to Threefish init - 

What it means

ThreefishEngine.Init only accepts KeyParameter (key only, no tweak) or ParametersWithTweak wrapping a KeyParameter. Any other ICipherParameters type falls through to the else branch and throws ArgumentException, appending the actual type name.

Source

Thrown at winPEAS/winPEASexe/winPEAS/3rdParty/BouncyCastle/crypto/engines/ThreefishEngine.cs:174

		public virtual void Init(bool forEncryption, ICipherParameters parameters)
		{
			byte[] keyBytes;
			byte[] tweakBytes;

			if (parameters is TweakableBlockCipherParameters)
			{
				TweakableBlockCipherParameters tParams = (TweakableBlockCipherParameters)parameters;
				keyBytes = tParams.Key.GetKey();
				tweakBytes = tParams.Tweak;
			}
			else if (parameters is KeyParameter)
			{
				keyBytes = ((KeyParameter)parameters).GetKey();
				tweakBytes = null;
			}
			else
			{
				throw new ArgumentException("Invalid parameter passed to Threefish init - "
					+ Platform.GetTypeName(parameters));
			}

			ulong[] keyWords = null;
			ulong[] tweakWords = null;

			if (keyBytes != null)
			{
				if (keyBytes.Length != this.blocksizeBytes)
				{
					throw new ArgumentException("Threefish key must be same size as block (" + blocksizeBytes
												+ " bytes)");
				}
				keyWords = new ulong[blocksizeWords];
				for (int i = 0; i < keyWords.Length; i++)
				{
					keyWords[i] = BytesToWord(keyBytes, i * 8);
				}

View on GitHub (pinned to 53fb989abc)

Solutions

1. Pass a KeyParameter directly for tweakless operation
2. Use new ParametersWithTweak(new KeyParameter(key), tweakBytes) when a tweak is required
3. Check the runtime type of your ICipherParameters before calling Init

Example fix

// before
engine.Init(true, new ParametersWithIV(new KeyParameter(key), iv));
// after
engine.Init(true, new ParametersWithTweak(new KeyParameter(key), tweak));

if (!(parameters is KeyParameter) && !(parameters is ParametersWithTweak))
    throw new ArgumentException("Threefish requires KeyParameter or ParametersWithTweak");

bool IsValidThreefishParameters(ICipherParameters p) => p is KeyParameter || (p is ParametersWithTweak wt && wt.Parameters is KeyParameter);

try { engine.Init(forEnc, parameters); }
catch (ArgumentException ex) { /* inspect ex.Message for the offending type name */ }

When it happens

Trigger: Calling Init with e.g. ParametersWithIV, ParametersWithRandom, ParametersWithSalt, or null in a position where a KeyParameter/ParametersWithTweak is expected.

Common situations: Copy-pasting Init code written for AES/CBC (which uses ParametersWithIV) and applying it to Threefish; wrapping the wrong parameter class when trying to supply a tweak.

Related errors

• Invalid blocksize - Threefish is defined with block size of
• Threefish key must be same size as block (
• Threefish tweak must be bytes
• Tweak must be words.
• Output buffer too short

AI-assisted analysis of peass-ng/PEASS-ng@53fb989abc (2026-09-02). Data as JSON: /api/errors/cd7512ee29a01429. Report an issue: GitHub.