gchq/CyberChef · error · OperationError

Invalid encoding

Error message

Invalid encoding

What it means

Thrown by Decode Text run() when the selected encoding name does not resolve to a code page id in the CHR_ENC_CODE_PAGES map. The args are nominally constrained by the operation's option list, so through the UI this is effectively unreachable; it surfaces only when the operation is invoked programmatically with an encoding string not present in the registry.

Source

Thrown at src/core/operations/DecodeText.mjs:53

        this.outputType = "string";
        this.args = [
            {
                "name": "Encoding",
                "type": "option",
                "value": Object.keys(CHR_ENC_CODE_PAGES)
            }
        ];
    }

    /**
     * @param {ArrayBuffer} input
     * @param {Object[]} args
     * @returns {string}
     */
    run(input, args) {
        const format = CHR_ENC_CODE_PAGES[args[0]];
        if (!format) {
            throw new OperationError("Invalid encoding");
        }
        return cptable.utils.decode(format, new Uint8Array(input));
    }

}

export default DecodeText;

View on GitHub (pinned to 4290ea7539)

Solutions

1. Use an exact encoding name from Object.keys(CHR_ENC_CODE_PAGES) (case-sensitive, e.g. 'UTF-8' not 'utf8').
2. If building a recipe dynamically, validate the encoding against the registry before invoking.
3. Regenerate the recipe in the current build so the option value matches the registry.

Example fix

// before
op.run(input, [{0: "utf8"}]);
// or
op.run(input, ["utf8"]); // not in registry

// after
op.run(input, ["UTF-8"]); // exact registry key

import { CHR_ENC_CODE_PAGES } from "src/core/lib/ChrEnc.mjs";

function isSupportedEncoding(name) {
    return Object.prototype.hasOwnProperty.call(CHR_ENC_CODE_PAGES, name);
}

/** @returns {boolean} */
function isValidCodePage(name) {
    return typeof name === "string"
        && Object.prototype.hasOwnProperty.call(CHR_ENC_CODE_PAGES, name);
}

try {
    out = decodeText.run(input, args);
} catch (e) {
    if (e instanceof OperationError && e.message === "Invalid encoding") {
        // pick a default (e.g. 'UTF-8') or surface supported list
        args[0] = "UTF-8";
        out = decodeText.run(input, args);
    } else throw e;
}

When it happens

Trigger: Calling run() directly with args[0] set to a string that is not a key of CHR_ENC_CODE_PAGES - e.g. 'utf-8' instead of 'UTF-8', a typo, an unsupported legacy code page name, or undefined after an arg mapping mistake.

Common situations: Programmatic/Node-API invocation passing a casing-mismatched or unregistered encoding name; a recipe imported with a stale encoding name removed in a newer build; an automation script hardcoding a charset string.

Related errors

• Invalid Base64 alphabet length (${alphabet.length}): ${alpha
• Byte length must be a positive integer
• unexpected character encountered: "${character}"
• Invalid 'Diff by' option.
• Invalid mode value

AI-assisted analysis of gchq/CyberChef@4290ea7539 (2026-08-13). Data as JSON: /api/errors/a3a7e312668ba9c3. Report an issue: GitHub.