svelte-kit-cookie-session-patch/dist/esm/utils/crypto/make-crypter.js

⚒️ Encrypted 'stateless' cookie sessions for SvelteKit

/**
 *
 *  This work is mostly copied over from `string-cipher` => `https://github.com/limplash/string-cipher`, but since it doesn't support esm(yet) i decided to copy
 *  only the bits needed for `svelte-kit-cookie-session`. Thank you limplash!
 *  MIT License
 *  Copyright (c) 2021 limplash
 *
 */
import { pbkdf2Sync, createDecipheriv, createCipheriv, randomBytes, } from "crypto";
const keyLengthHint = (algo) => {
    switch (algo) {
        case "aes-256-gcm":
            return 32;
        case "aes-192-gcm":
            return 24;
        case "aes-128-gcm":
            return 16;
        default:
            throw new Error(`Unsupported algorithm ${algo}`);
    }
};
export const makeStringDecrypterSync = ({ algorithm, inputEncoding = "base64", stringEncoding = "utf8", ivLength = 12, authTagLength = 16, saltLength = 32, iterations = 1, digest = "sha256", }) => (text, password) => {
    const buffer = Buffer.from(text, inputEncoding);
    // data is packed in this sequence [salt iv tag cipherTest]
    const tagStartIndex = saltLength + ivLength;
    const textStartIndex = tagStartIndex + authTagLength;
    const salt = buffer.slice(0, saltLength);
    const iv = buffer.slice(saltLength, tagStartIndex);
    const tag = buffer.slice(tagStartIndex, textStartIndex);
    const cipherText = buffer.slice(textStartIndex);
    const key = pbkdf2Sync(password, salt, iterations, keyLengthHint(algorithm), digest);
    const decipher = createDecipheriv(algorithm, key, iv, {
        authTagLength,
    }).setAuthTag(tag);
    //@ts-ignore
    return `${decipher.update(cipherText, "binary", stringEncoding)}${decipher.final(stringEncoding)}`;
};
export const makeStringEncrypterSync = ({ algorithm, outputEncoding = "base64", stringEncoding = "utf8", authTagLength = 16, ivLength = 12, saltLength = 32, iterations = 1, digest = "sha256", }) => (text, password) => {
    const iv = randomBytes(ivLength);
    const salt = randomBytes(saltLength);
    const key = pbkdf2Sync(password, salt, iterations, keyLengthHint(algorithm), digest);
    const cipher = createCipheriv(algorithm, key, iv, { authTagLength });
    const cipherText = Buffer.concat([
        cipher.update(text, stringEncoding),
        cipher.final(),
    ]);
    return Buffer.concat([salt, iv, cipher.getAuthTag(), cipherText]).toString(outputEncoding);
};