46 lines
1.3 KiB
TypeScript
46 lines
1.3 KiB
TypeScript
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import { IEncryptionScheme, ICryptoProvider } from './abstract'
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// returns tuple: [key, iv]
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export async function generateKeyAndIvFromNonce(
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crypto: ICryptoProvider,
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serverNonce: Buffer,
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newNonce: Buffer
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): Promise<[Buffer, Buffer]> {
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const hash1 = await crypto.sha1(Buffer.concat([newNonce, serverNonce]))
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const hash2 = await crypto.sha1(Buffer.concat([serverNonce, newNonce]))
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const hash3 = await crypto.sha1(Buffer.concat([newNonce, newNonce]))
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const key = Buffer.concat([hash1, hash2.slice(0, 12)])
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const iv = Buffer.concat([hash2.slice(12, 20), hash3, newNonce.slice(0, 4)])
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return [key, iv]
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}
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export async function createAesIgeForMessage(
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crypto: ICryptoProvider,
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authKey: Buffer,
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messageKey: Buffer,
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client: boolean
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): Promise<IEncryptionScheme> {
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const x = client ? 0 : 8
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const sha256a = await crypto.sha256(
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Buffer.concat([messageKey, authKey.slice(x, 36 + x)])
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)
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const sha256b = await crypto.sha256(
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Buffer.concat([authKey.slice(40 + x, 76 + x), messageKey])
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)
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const key = Buffer.concat([
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sha256a.slice(0, 8),
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sha256b.slice(8, 24),
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sha256a.slice(24, 32),
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])
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const iv = Buffer.concat([
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sha256b.slice(0, 8),
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sha256a.slice(8, 24),
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sha256b.slice(24, 32),
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])
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return crypto.createAesIge(key, iv)
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}
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