Method run

src/core/operations/GOSTDecrypt.mjs:99–147

* @param {string} input * @param {Object[]} args * @returns {string}

(input, args)

     * @returns {string}
     */
    async run(input, args) {
        const [keyObj, ivObj, inputType, outputType, version, sBox, blockMode, keyMeshing, padding] = args;

        const key = toHexFast(Utils.convertToByteArray(keyObj.string, keyObj.option));
        const iv = toHexFast(Utils.convertToByteArray(ivObj.string, ivObj.option));
        input = inputType === "Hex" ? input : toHexFast(Utils.strToArrayBuffer(input));

        let blockLength, versionNum;
        switch (version) {
            case "GOST 28147 (1989)":
                versionNum = 1989;
                blockLength = 64;
                break;
            case "GOST R 34.12 (Magma, 2015)":
                versionNum = 2015;
                blockLength = 64;
                break;
            case "GOST R 34.12 (Kuznyechik, 2015)":
                versionNum = 2015;
                blockLength = 128;
                break;
            default:
                throw new OperationError(`Unknown algorithm version: ${version}`);
        }

        const sBoxVal = versionNum === 1989 ? sBox : null;

        const algorithm = {
            version: versionNum,
            length: blockLength,
            mode: "ES",
            sBox: sBoxVal,
            block: blockMode,
            keyMeshing: keyMeshing,
            padding: padding
        };

        try {
            const Hex = CryptoGost.coding.Hex;
            if (iv) algorithm.iv = Hex.decode(iv);

            const cipher = GostEngine.getGostCipher(algorithm);
            const out = Hex.encode(cipher.decrypt(Hex.decode(key), Hex.decode(input)));

            return outputType === "Hex" ? out : Utils.byteArrayToChars(fromHex(out));
        } catch (err) {
            throw new OperationError(err);
        }
    }

}