f63d0c9afe
- Scaffolds a new Rust crate `wasm/sss_recovery` for constant-time Shamir's Secret Sharing over GF(256) with strict Wasm `zeroize` - Implements purely typed BIP-39 fallback mapped via Deno WebCrypto in `ui/utils/bip39.ts` - Migrates `server/recovery.ts` logic mapping Device/Voucher + Server shares with Valkey rate-limiting - Applies mandatory in-memory JS zeroization on all reconstructed buffers Co-authored-by: mrteye <1945243+mrteye@users.noreply.github.com>
72 lines
2.2 KiB
TypeScript
72 lines
2.2 KiB
TypeScript
import { WORDLIST } from "./bip39_wordlist.ts";
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export async function entropyToMnemonic(entropy: Uint8Array): Promise<string> {
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if (entropy.length < 16 || entropy.length > 32 || entropy.length % 4 !== 0) {
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throw new Error("Invalid entropy length");
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}
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const entropyBits = Array.from(entropy)
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.map((b) => b.toString(2).padStart(8, "0"))
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.join("");
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const entropyBuffer = new Uint8Array(entropy.length);
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entropyBuffer.set(entropy);
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const hashBuffer = await crypto.subtle.digest("SHA-256", entropyBuffer);
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const hashBits = Array.from(new Uint8Array(hashBuffer))
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.map((b) => b.toString(2).padStart(8, "0"))
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.join("");
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const checksumLength = entropy.length / 4;
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const checksum = hashBits.slice(0, checksumLength);
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const bits = entropyBits + checksum;
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const chunks = bits.match(/(.{1,11})/g) || [];
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const mnemonic = chunks.map((binaryStr) => {
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const index = parseInt(binaryStr, 2);
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return WORDLIST[index];
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});
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return mnemonic.join(" ");
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}
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export async function mnemonicToEntropy(mnemonic: string): Promise<Uint8Array> {
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const words = mnemonic.normalize("NFKD").trim().split(/\s+/);
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if (words.length % 3 !== 0) {
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throw new Error("Invalid mnemonic length");
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}
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const bits = words
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.map((word) => {
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const index = WORDLIST.indexOf(word);
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if (index === -1) {
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throw new Error(`Invalid word in mnemonic: ${word}`);
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}
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return index.toString(2).padStart(11, "0");
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})
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.join("");
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const dividerIndex = Math.floor(bits.length / 33) * 32;
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const entropyBits = bits.slice(0, dividerIndex);
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const checksumBits = bits.slice(dividerIndex);
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const entropy = new Uint8Array(entropyBits.length / 8);
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for (let i = 0; i < entropy.length; i++) {
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entropy[i] = parseInt(entropyBits.slice(i * 8, (i + 1) * 8), 2);
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}
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const hashBuffer = await crypto.subtle.digest("SHA-256", entropy);
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const hashBits = Array.from(new Uint8Array(hashBuffer))
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.map((b) => b.toString(2).padStart(8, "0"))
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.join("");
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const expectedChecksum = hashBits.slice(0, checksumBits.length);
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if (expectedChecksum !== checksumBits) {
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// Explicitly zeroize on failure
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entropy.fill(0);
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throw new Error("Invalid mnemonic checksum");
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}
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return entropy;
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}
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