working rss feed to nostr publish
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"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.BinaryFF1 = exports.FF1 = exports.encryptBlock = void 0;
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const utils_js_1 = require("./utils.js");
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// Format-preserving encryption algorithm (FPE-FF1) specified in NIST Special Publication 800-38G.
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// https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-38G.pdf
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// Utils
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function toBytesBE(num, length) {
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let hex = num.toString(16);
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hex = hex.length & 1 ? `0${hex}` : hex;
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if (length)
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hex = hex.padStart(length * 2, '00');
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const len = hex.length / 2;
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const u8 = new Uint8Array(len);
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for (let j = 0, i = 0; i < hex.length && i < len * 2; i += 2, j++)
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u8[j] = parseInt(hex[i] + hex[i + 1], 16);
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return u8;
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}
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function fromBytesBE(bytes) {
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let value = 0n;
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for (let i = bytes.length - 1, j = 0; i >= 0; i--, j++)
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value += (BigInt(bytes[i]) & 255n) << (8n * BigInt(j));
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return value;
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}
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function mod(a, b) {
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const result = a % b;
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return result >= 0 ? result : b + result;
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}
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// AES stuff
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const BLOCK_LEN = 16;
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const IV = new Uint8Array(BLOCK_LEN);
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async function encryptBlock(msg, key) {
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if (key.length !== 16 && key.length !== 32)
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throw new Error('Invalid key length');
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const cr = (0, utils_js_1.getWebcryptoSubtle)();
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const mode = { name: `AES-CBC`, length: key.length * 8 };
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const wKey = await cr.importKey('raw', key, mode, true, ['encrypt']);
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const cipher = await cr.encrypt({ name: `aes-cbc`, iv: IV, counter: IV, length: 64 }, wKey, msg);
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return new Uint8Array(cipher).subarray(0, 16);
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}
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exports.encryptBlock = encryptBlock;
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function NUMradix(radix, data) {
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let res = 0n;
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for (let i of data)
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res = res * BigInt(radix) + BigInt(i);
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return res;
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}
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async function getRound(radix, key, tweak, x) {
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if (radix > 2 ** 16 - 1)
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throw new Error(`Invalid radix: ${radix}`);
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// radix**minlen ≥ 100
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const minLen = Math.ceil(Math.log(100) / Math.log(radix));
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const maxLen = 2 ** 32 - 1;
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// 2 ≤ minlen ≤ maxlen < 2**32
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if (2 > minLen || minLen > maxLen || maxLen >= 2 ** 32)
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throw new Error('Invalid radix: 2 ≤ minlen ≤ maxlen < 2**32');
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if (x.length < minLen || x.length > maxLen)
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throw new Error('X is outside minLen..maxLen bounds');
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const u = Math.floor(x.length / 2);
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const v = x.length - u;
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const b = Math.ceil(Math.ceil(v * Math.log2(radix)) / 8);
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const d = 4 * Math.ceil(b / 4) + 4;
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const padding = mod(-tweak.length - b - 1, 16);
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// P = [1]1 || [2]1 || [1]1 || [radix]3 || [10]1 || [u mod 256]1 || [n]4 || [t]4.
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const P = new Uint8Array([1, 2, 1, 0, 0, 0, 10, u, 0, 0, 0, 0, 0, 0, 0, 0]);
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const view = new DataView(P.buffer);
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view.setUint16(4, radix, false);
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view.setUint32(8, x.length, false);
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view.setUint32(12, tweak.length, false);
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// Q = T || [0](−t−b−1) mod 16 || [i]1 || [NUMradix(B)]b.
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const PQ = new Uint8Array(P.length + tweak.length + padding + 1 + b);
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PQ.set(P);
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P.fill(0);
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PQ.set(tweak, P.length);
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const round = async (A, B, i, decrypt = false) => {
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// Q = ... || [i]1 || [NUMradix(B)]b.
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PQ[PQ.length - b - 1] = i;
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if (b)
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PQ.set(toBytesBE(NUMradix(radix, B), b), PQ.length - b);
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// PRF
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let r = new Uint8Array(16);
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for (let j = 0; j < PQ.length / BLOCK_LEN; j++) {
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for (let i = 0; i < BLOCK_LEN; i++)
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r[i] ^= PQ[j * BLOCK_LEN + i];
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r.set(await encryptBlock(r, key));
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}
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// Let S be the first d bytes of the following string of ⎡d/16⎤ blocks:
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// R || CIPHK(R ⊕[1]16) || CIPHK(R ⊕[2]16) ...CIPHK(R ⊕[⎡d / 16⎤ – 1]16).
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let s = Array.from(r);
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for (let j = 1; s.length < d; j++) {
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const block = toBytesBE(BigInt(j), 16);
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for (let k = 0; k < BLOCK_LEN; k++)
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block[k] ^= r[k];
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s.push(...Array.from(await encryptBlock(block, key)));
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}
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let y = fromBytesBE(Uint8Array.from(s.slice(0, d)));
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s.fill(0);
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if (decrypt)
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y = -y;
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const m = i % 2 === 0 ? u : v;
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let c = mod(NUMradix(radix, A) + y, BigInt(radix) ** BigInt(m));
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// STR(radix, m, c)
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const C = Array(m).fill(0);
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for (let i = 0; i < m; i++, c /= BigInt(radix))
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C[m - 1 - i] = Number(c % BigInt(radix));
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A.fill(0);
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A = B;
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B = C;
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return [A, B];
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};
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const destroy = () => PQ.fill(0);
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return { u, round, destroy };
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}
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const EMPTY_BUF = new Uint8Array([]);
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function FF1(radix, key, tweak = EMPTY_BUF) {
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const PQ = getRound.bind(null, radix, key, tweak);
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return {
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async encrypt(x) {
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const { u, round, destroy } = await PQ(x);
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let [A, B] = [x.slice(0, u), x.slice(u)];
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for (let i = 0; i < 10; i++)
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[A, B] = await round(A, B, i);
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destroy();
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const res = A.concat(B);
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A.fill(0);
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B.fill(0);
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return res;
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},
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async decrypt(x) {
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const { u, round, destroy } = await PQ(x);
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// The FF1.Decrypt algorithm is similar to the FF1.Encrypt algorithm;
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// the differences are in Step 6, where:
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// 1) the order of the indices is reversed,
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// 2) the roles of A and B are swapped
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// 3) modular addition is replaced by modular subtraction, in Step 6vi.
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let [B, A] = [x.slice(0, u), x.slice(u)];
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for (let i = 9; i >= 0; i--)
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[A, B] = await round(A, B, i, true);
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destroy();
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const res = B.concat(A);
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A.fill(0);
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B.fill(0);
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return res;
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},
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};
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}
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exports.FF1 = FF1;
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// Binary string which encodes each byte in little-endian byte order
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const binLE = {
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encode(bytes) {
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const x = [];
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for (let i = 0; i < bytes.length; i++) {
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for (let j = 0, tmp = bytes[i]; j < 8; j++, tmp >>= 1)
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x.push(tmp & 1);
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}
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return x;
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},
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decode(b) {
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if (b.length % 8)
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throw new Error('Invalid binary string');
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const res = new Uint8Array(b.length / 8);
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for (let i = 0, j = 0; i < res.length; i++) {
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res[i] = b[j++] | (b[j++] << 1) | (b[j++] << 2) | (b[j++] << 3);
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res[i] |= (b[j++] << 4) | (b[j++] << 5) | (b[j++] << 6) | (b[j++] << 7);
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}
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return res;
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},
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};
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function BinaryFF1(key, tweak = EMPTY_BUF) {
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const ff1 = FF1(2, key, tweak);
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return {
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encrypt: async (x) => binLE.decode(await ff1.encrypt(binLE.encode(x))),
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decrypt: async (x) => binLE.decode(await ff1.decrypt(binLE.encode(x))),
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};
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}
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exports.BinaryFF1 = BinaryFF1;
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//# sourceMappingURL=ff1.js.map
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