Rajeh Taher
97 lines
2.9 KiB
TypeScript
97 lines
2.9 KiB
TypeScript
import { calculateSignature, verifySignature } from 'libsignal/src/curve'
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import { proto } from '../../../WAProto/index.js'
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import { CiphertextMessage } from './ciphertext-message'
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interface SenderKeyMessageStructure {
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id: number
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iteration: number
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ciphertext: string | Buffer
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}
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export class SenderKeyMessage extends CiphertextMessage {
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private readonly SIGNATURE_LENGTH = 64
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private readonly messageVersion: number
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private readonly keyId: number
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private readonly iteration: number
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private readonly ciphertext: Uint8Array
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private readonly signature: Uint8Array
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private readonly serialized: Uint8Array
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constructor(
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keyId?: number | null,
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iteration?: number | null,
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ciphertext?: Uint8Array | null,
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signatureKey?: Uint8Array | null,
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serialized?: Uint8Array | null
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) {
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super()
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if (serialized) {
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const version = serialized[0]!
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const message = serialized.slice(1, serialized.length - this.SIGNATURE_LENGTH)
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const signature = serialized.slice(-1 * this.SIGNATURE_LENGTH)
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const senderKeyMessage = proto.SenderKeyMessage.decode(message).toJSON() as SenderKeyMessageStructure
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this.serialized = serialized
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this.messageVersion = (version & 0xff) >> 4
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this.keyId = senderKeyMessage.id
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this.iteration = senderKeyMessage.iteration
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this.ciphertext =
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typeof senderKeyMessage.ciphertext === 'string'
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? Buffer.from(senderKeyMessage.ciphertext, 'base64')
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: senderKeyMessage.ciphertext
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this.signature = signature
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} else {
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const version = (((this.CURRENT_VERSION << 4) | this.CURRENT_VERSION) & 0xff) % 256
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const ciphertextBuffer = Buffer.from(ciphertext!)
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const message = proto.SenderKeyMessage.encode(
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proto.SenderKeyMessage.create({
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id: keyId!,
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iteration: iteration!,
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ciphertext: ciphertextBuffer
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})
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).finish()
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const signature = this.getSignature(signatureKey!, Buffer.concat([Buffer.from([version]), message]))
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this.serialized = Buffer.concat([Buffer.from([version]), message, Buffer.from(signature)])
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this.messageVersion = this.CURRENT_VERSION
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this.keyId = keyId!
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this.iteration = iteration!
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this.ciphertext = ciphertextBuffer
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this.signature = signature
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}
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}
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public getKeyId(): number {
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return this.keyId
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}
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public getIteration(): number {
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return this.iteration
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}
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public getCipherText(): Uint8Array {
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return this.ciphertext
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}
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public verifySignature(signatureKey: Uint8Array): void {
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const part1 = this.serialized.slice(0, this.serialized.length - this.SIGNATURE_LENGTH)
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const part2 = this.serialized.slice(-1 * this.SIGNATURE_LENGTH)
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const res = verifySignature(signatureKey, part1, part2)
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if (!res) throw new Error('Invalid signature!')
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}
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private getSignature(signatureKey: Uint8Array, serialized: Uint8Array): Uint8Array {
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return Buffer.from(calculateSignature(signatureKey, serialized))
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}
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public serialize(): Uint8Array {
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return this.serialized
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}
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public getType(): number {
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return 4
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}
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}
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