23 lines
880 B
TypeScript
23 lines
880 B
TypeScript
const u8aFromHex = (hexString:string) =>
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Uint8Array.from(hexString.match(/.{1,2}/g).map((byte) => parseInt(byte, 16)))
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const is16BitHex = (maybeHex: string | undefined) =>
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maybeHex && maybeHex.length % 2 === 0 && !/[^a-fA-F0-9]/u.test(maybeHex)
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export function decryptSessionBytes(cypher: Uint8Array, keyString: string): Promise<Uint8Array> {
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if (keyString.length !== 64) {
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return Promise.reject("Wrong key string format")
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}
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const [hexKey, hexIV] = keyString.match(/.{32}/g)
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if (!is16BitHex(hexIV) || !is16BitHex(hexKey)) {
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return Promise.reject("Wrong key/iv pair")
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}
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const byteKey = u8aFromHex(hexKey)
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const iv = u8aFromHex(hexIV)
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return crypto.subtle.importKey("raw", byteKey, { name: "AES-CBC" }, false, ["decrypt"])
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.then(key => crypto.subtle.decrypt({ name: "AES-CBC", iv: iv}, key, cypher))
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.then((bArray: ArrayBuffer) => new Uint8Array(bArray))
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}
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