nostr-tools/nip04.ts

67 lines
1.5 KiB
TypeScript

import {randomBytes} from '@noble/hashes/utils'
import * as secp256k1 from '@noble/secp256k1'
import {base64} from '@scure/base'
import {utf8Decoder, utf8Encoder} from './utils'
export async function encrypt(
privkey: string,
pubkey: string,
text: string
): Promise<string> {
const key = secp256k1.getSharedSecret(privkey, '02' + pubkey)
const normalizedKey = getNormalizedX(key)
let iv = Uint8Array.from(randomBytes(16))
let plaintext = utf8Encoder.encode(text)
let cryptoKey = await crypto.subtle.importKey(
'raw',
normalizedKey,
{name: 'AES-CBC'},
false,
['encrypt']
)
let ciphertext = await crypto.subtle.encrypt(
{name: 'AES-CBC', iv},
cryptoKey,
plaintext
)
let ctb64 = base64.encode(new Uint8Array(ciphertext))
let ivb64 = base64.encode(new Uint8Array(iv.buffer))
return `${ctb64}?iv=${ivb64}`
}
export async function decrypt(
privkey: string,
pubkey: string,
data: string
): Promise<string> {
let [ctb64, ivb64] = data.split('?iv=')
let key = secp256k1.getSharedSecret(privkey, '02' + pubkey)
let normalizedKey = getNormalizedX(key)
let cryptoKey = await crypto.subtle.importKey(
'raw',
normalizedKey,
{name: 'AES-CBC'},
false,
['decrypt']
)
let ciphertext = base64.decode(ctb64)
let iv = base64.decode(ivb64)
let plaintext = await crypto.subtle.decrypt(
{name: 'AES-CBC', iv},
cryptoKey,
ciphertext
)
let text = utf8Decoder.decode(plaintext)
return text
}
function getNormalizedX(key: Uint8Array): Uint8Array {
return key.slice(1, 33)
}