peass-ng/PEASS-ng · error · ArgumentException

Unknown S-Box - possible types: "Default", "E-Test", "E-A",

Error message

Unknown S-Box - possible types: "Default", "E-Test", "E-A", "E-B", "E-C", "E-D", "D-Test", "D-A".

What it means

Gost28147Engine.GetSBox looks up the requested S-Box by uppercase name in its static sBoxes table and throws ArgumentException when the name is not one of the eight supported identifiers (Default, E-Test, E-A, E-B, E-C, E-D, D-Test, D-A).

Source

Thrown at winPEAS/winPEASexe/winPEAS/3rdParty/BouncyCastle/crypto/engines/Gost28147Engine.cs:360

			outBytes[outOff + 3] = (byte)(num >> 24);
			outBytes[outOff + 2] = (byte)(num >> 16);
			outBytes[outOff + 1] = (byte)(num >> 8);
			outBytes[outOff] = (byte)num;
		}

		/**
		* Return the S-Box associated with SBoxName
		* @param sBoxName name of the S-Box
		* @return byte array representing the S-Box
		*/
		public static byte[] GetSBox(
			string sBoxName)
		{
			byte[] sBox = (byte[])sBoxes[Platform.ToUpperInvariant(sBoxName)];

			if (sBox == null)
			{
				throw new ArgumentException("Unknown S-Box - possible types: "
					+ "\"Default\", \"E-Test\", \"E-A\", \"E-B\", \"E-C\", \"E-D\", \"D-Test\", \"D-A\".");
			}

			return Arrays.Clone(sBox);
		}

		public static string GetSBoxName(byte[] sBox)
		{
			foreach (string name in sBoxes.Keys)
			{
				byte[] sb = (byte[])sBoxes[name];
				if (Arrays.AreEqual(sb, sBox))
				{
					return name;
				}
			}

			throw new ArgumentException("SBOX provided did not map to a known one");

View on GitHub (pinned to 53fb989abc)

Solutions

Use one of the exact names: Default, E-Test, E-A, E-B, E-C, E-D, D-Test, D-A
Normalize the parameter-set identifier to one of the supported names before lookup
Normalize your own input with ToUpperInvariant and trim, since lookup is case-insensitive via Platform.ToUpperInvariant but exact-match on content

Example fix

// before
byte[] sbox = Gost28147Engine.GetSBox("tc26");
// after
byte[] sbox = Gost28147Engine.GetSBox("E-A");

Defensive patterns

Strategy: validation

Validate before calling

static readonly HashSet<string> ValidSBoxes = new HashSet<string>{"Default","E-Test","E-A","E-B","E-C","E-D","D-Test","D-A"};
if (!ValidSBoxes.Contains(sBoxName)) throw new ArgumentException("Unsupported S-Box: " + sBoxName);

Type guard

bool IsKnownSBoxName(string name) => name != null && new[]{"Default","E-Test","E-A","E-B","E-C","E-D","D-Test","D-A"}.Contains(name, StringComparer.OrdinalIgnoreCase);

Try / catch

try { byte[] sbox = Gost28147Engine.GetSBox(name); }
catch (ArgumentException ex) { /* fall back to "Default" or surface config error */ }

Prevention

Centralize S-Box names in an enum or constants class
Trim and normalize external config values before lookup
Validate S-Box config at startup, not at first use

When it happens

Trigger: Calling GetSBox("E-TEST"), GetSBox("Default ") with whitespace, GetSBox("id-tc26-gost...") or any misspelled/unsupported S-Box name.

Common situations: Using RFC/TC-26 S-Box parameter set names that this older BouncyCastle port does not support; copy-pasting names with wrong case handled by caller, trailing spaces, or hyphen/underscore confusion.

Related errors

AI-assisted analysis of peass-ng/PEASS-ng@53fb989abc (2026-09-02). Data as JSON: /api/errors/adae9a44acda300b. Report an issue: GitHub.