72 lines
1.7 KiB
TypeScript
72 lines
1.7 KiB
TypeScript
export class Hex {
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static encode(buffer: ArrayBuffer): string {
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let s = ''
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for (const i of new Uint8Array(buffer)) {
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s += i.toString(16).padStart(2, '0')
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}
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return s
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}
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static decode(s: string): ArrayBuffer {
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const size = s.length / 2
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const buffer = new Uint8Array(size)
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for (let i = 0; i < size; i++) {
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const idx = i * 2
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const segment = s.slice(idx, idx + 2)
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buffer[i] = parseInt(segment, 16)
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}
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return buffer
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}
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}
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const ALG = 'AES-GCM'
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export function getRandomBytes(size = 16): Uint8Array {
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return window.crypto.getRandomValues(new Uint8Array(size))
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}
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export function getKeyFromString(password: string) {
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return window.crypto.subtle.importKey(
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'raw',
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new TextEncoder().encode(password),
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'PBKDF2',
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false,
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['deriveBits', 'deriveKey']
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)
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}
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export async function getDerivedForKey(key: CryptoKey, salt: ArrayBuffer) {
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const iterations = 100_000
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return window.crypto.subtle.deriveKey(
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{
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name: 'PBKDF2',
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salt,
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iterations,
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hash: 'SHA-512',
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},
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key,
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{ name: ALG, length: 256 },
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true,
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['encrypt', 'decrypt']
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)
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}
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export async function encrypt(plaintext: string, key: CryptoKey) {
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const salt = getRandomBytes(16)
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const derived = await getDerivedForKey(key, salt)
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const iv = getRandomBytes(16)
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const encrypted = await window.crypto.subtle.encrypt(
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{ name: ALG, iv },
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derived,
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new TextEncoder().encode(plaintext)
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)
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return [salt, iv, encrypted].map(Hex.encode).join(':')
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}
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export async function decrypt(ciphertext: string, key: CryptoKey) {
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const [salt, iv, encrypted] = ciphertext.split(':').map(Hex.decode)
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const derived = await getDerivedForKey(key, salt)
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const plaintext = await window.crypto.subtle.decrypt({ name: ALG, iv }, derived, encrypted)
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return new TextDecoder().decode(plaintext)
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}
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