47 lines
1.3 KiB
TypeScript
47 lines
1.3 KiB
TypeScript
import {base64} from '@scure/base'
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import {randomBytes} from '@noble/hashes/utils'
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import {secp256k1} from '@noble/curves/secp256k1'
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import {sha256} from '@noble/hashes/sha256'
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import {xchacha20} from '@noble/ciphers/chacha'
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import {utf8Decoder, utf8Encoder} from './utils.ts'
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export const getSharedSecret = (privkey: string, pubkey: string): Uint8Array =>
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sha256(secp256k1.getSharedSecret(privkey, '02' + pubkey).subarray(1, 33))
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export function encrypt(key: Uint8Array, text: string, v = 1) {
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if (v !== 1) {
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throw new Error('NIP44: unknown encryption version')
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}
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const nonce = randomBytes(24)
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const plaintext = utf8Encoder.encode(text)
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const ciphertext = xchacha20(key, nonce, plaintext)
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const payload = new Uint8Array(25 + ciphertext.length)
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payload.set([v], 0)
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payload.set(nonce, 1)
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payload.set(ciphertext, 25)
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return base64.encode(payload)
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}
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export function decrypt(key: Uint8Array, payload: string) {
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let data
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try {
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data = base64.decode(payload)
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} catch (e) {
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throw new Error(`NIP44: failed to base64 decode payload: ${e}`)
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}
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if (data[0] !== 1) {
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throw new Error(`NIP44: unknown encryption version: ${data[0]}`)
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}
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const nonce = data.slice(1, 25)
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const ciphertext = data.slice(25)
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const plaintext = xchacha20(key, nonce, ciphertext)
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return utf8Decoder.decode(plaintext)
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}
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