gchq/CyberChef · error · OperationError

Invalid key length: ${key.length} bytes PRESENT uses a key

Error message

Invalid key length: ${key.length} bytes

PRESENT uses a key length of 10 bytes (80 bits) or 16 bytes (128 bits).

What it means

Identical validation to error 547 but in the encrypt operation. The PRESENT block cipher requires a key of exactly 10 bytes (80 bits) or 16 bytes (128 bits). The encrypt operation validates the key length before calling encryptPRESENT.

Source

Thrown at src/core/operations/PRESENTEncrypt.mjs:77

                "name": "Padding",
                "type": "option",
                "value": ["PKCS5", "NO", "ZERO", "RANDOM", "BIT"]
            }
        ];
    }

    /**
     * @param {string} input
     * @param {Object[]} args
     * @returns {string}
     */
    run(input, args) {
        const key = Utils.convertToByteArray(args[0].string, args[0].option),
            iv = Utils.convertToByteArray(args[1].string, args[1].option),
            [,, mode, inputType, outputType, padding] = args;

        if (key.length !== 10 && key.length !== 16)
            throw new OperationError(`Invalid key length: ${key.length} bytes

PRESENT uses a key length of 10 bytes (80 bits) or 16 bytes (128 bits).`);

        if (iv.length !== 8 && mode !== "ECB")
            throw new OperationError(`Invalid IV length: ${iv.length} bytes

PRESENT uses an IV length of 8 bytes (64 bits).
Make sure you have specified the type correctly (e.g. Hex vs UTF8).`);

        input = Utils.convertToByteArray(input, inputType);
        const output = encryptPRESENT(input, key, iv, mode, padding);
        return outputType === "Hex" ? toHex(output, "") : Utils.byteArrayToUtf8(output);
    }

}

export default PRESENTEncrypt;

View on GitHub (pinned to 4290ea7539)

Solutions

1. Provide exactly 10 or 16 bytes of key material
2. Double-check the key encoding option (Hex vs UTF8 vs Base64) matches your key representation
3. For hex keys, use 20 hex chars (10 bytes) or 32 hex chars (16 bytes) with the Hex option

Example fix

// before: key="aabbccddeeff0011", option="Hex" -> 8 bytes (FAILS)
// after:  key="aabbccddeeff00112233", option="Hex" -> 10 bytes (OK for 80-bit)

// Pre-check: validate key length before calling the operation
const keyBytes = Utils.convertToByteArray(keyString, keyOption);
if (keyBytes.length !== 10 && keyBytes.length !== 16) {
  throw new Error(`Key must be 10 or 16 bytes, got ${keyBytes.length}. Check encoding option.`);
}

function isValidPresentKey(keyBytes) {
  return keyBytes.length === 10 || keyBytes.length === 16;
}

When it happens

Trigger: The key argument, after convertToByteArray with the selected encoding option, yields a byte array whose length is not 10 or 16. Encoding mismatch is the most common cause — e.g., a hex key string interpreted as UTF8 doubles the effective byte count.

Common situations: User enters a hex key with the encoding option left on UTF8, producing the wrong byte count. User provides a key intended for a different cipher. Multibyte UTF8 characters inflate the byte count unexpectedly.

Related errors

• Invalid key length: ${key.length} bytes PRESENT uses a key
• Invalid IV length: ${iv.length} bytes PRESENT uses an IV le
• Invalid IV length: ${iv.length} bytes PRESENT uses an IV le
• Invalid key length: ${key.length} bytes Blowfish's key leng
• Invalid key length: ${key.length} bytes Blowfish's key leng

AI-assisted analysis of gchq/CyberChef@4290ea7539 (2026-08-13). Data as JSON: /api/errors/f7a7d3f6b7d34d54. Report an issue: GitHub.