Differential D6995 Diff 24128 web/database/utils/worker-crypto-utils.js

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				// @flow

				const ENCRYPTION_ALGORITHM = 'AES-GCM';

				type EncryptedData = {
				+iv: BufferSource,
				+ciphertext: Uint8Array,
				};

				function generateDatabaseCryptoKey(): Promise<CryptoKey> {
				return crypto.subtle.generateKey(
				{
				name: ENCRYPTION_ALGORITHM,
				length: 256,
				},
				false,
				['encrypt', 'decrypt'],
				);
				}

				function generateIV(): BufferSource {
				return crypto.getRandomValues(new Uint8Array(12));
				}

				async function encryptDatabaseFile(
				data: Uint8Array,
				key: CryptoKey,
				): Promise<EncryptedData> {
				const iv = generateIV();
				const ciphertext = await crypto.subtle.encrypt(
				{
				name: ENCRYPTION_ALGORITHM,
				iv: iv,
				},
				key,
				data,
				);
				return {
				ciphertext: new Uint8Array(ciphertext),
				iv,
				};
				}

				async function decryptDatabaseFile(
				encryptedData: EncryptedData,
				key: CryptoKey,
				): Promise<Uint8Array> {
				const { ciphertext, iv } = encryptedData;
				const decrypted = await crypto.subtle.decrypt(
				{
				name: ENCRYPTION_ALGORITHM,
				iv,
				},
				key,
				ciphertext,
				);
				return new Uint8Array(decrypted);
				}

				export { generateDatabaseCryptoKey, encryptDatabaseFile, decryptDatabaseFile };