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29 lines
836 B
29 lines
836 B
3 years ago
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const fromHexString = hexString =>
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new Uint8Array(hexString.match(/.{1,2}/g).map(byte => parseInt(byte, 16)));
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const toHexString = bytes =>
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bytes.reduce((str, byte) => str + byte.toString(16).padStart(2, '0'), '');
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onmessage = async (e) => {
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const seed = fromHexString(e.data.seedHex);
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const target = e.data.target;
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const fullBuf = new ArrayBuffer(seed.byteLength*2);
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const fullBufSeed = new Uint8Array(fullBuf, 0, seed.byteLength);
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seed.forEach((v, i) => fullBufSeed[i] = v);
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const randBuf = new Uint8Array(fullBuf, seed.byteLength);
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while (true) {
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crypto.getRandomValues(randBuf);
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const digest = await crypto.subtle.digest('SHA-512', fullBuf);
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const digestView = new DataView(digest);
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if (digestView.getUint32(0) < target) {
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postMessage(toHexString(randBuf));
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return;
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}
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}
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};
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