106 lines
3.8 KiB
JavaScript
106 lines
3.8 KiB
JavaScript
// nip44.ts
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import { chacha20 } from "@noble/ciphers/chacha";
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import { ensureBytes, equalBytes } from "@noble/ciphers/utils";
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import { secp256k1 } from "@noble/curves/secp256k1";
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import { hkdf } from "@noble/hashes/hkdf";
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import { hmac } from "@noble/hashes/hmac";
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import { sha256 } from "@noble/hashes/sha256";
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import { concatBytes, randomBytes } from "@noble/hashes/utils";
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import { base64 } from "@scure/base";
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// utils.ts
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var utf8Decoder = new TextDecoder("utf-8");
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var utf8Encoder = new TextEncoder();
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// nip44.ts
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var utils = {
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v2: {
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maxPlaintextSize: 65536 - 128,
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minCiphertextSize: 100,
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maxCiphertextSize: 102400,
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getConversationKey(privkeyA, pubkeyB) {
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const key = secp256k1.getSharedSecret(privkeyA, "02" + pubkeyB);
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return key.subarray(1, 33);
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},
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getMessageKeys(conversationKey, salt) {
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const keys = hkdf(sha256, conversationKey, salt, "nip44-v2", 76);
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return {
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encryption: keys.subarray(0, 32),
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nonce: keys.subarray(32, 44),
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auth: keys.subarray(44, 76)
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};
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},
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calcPadding(len) {
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if (!Number.isSafeInteger(len) || len < 0)
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throw new Error("expected positive integer");
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if (len <= 32)
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return 32;
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const nextpower = 1 << Math.floor(Math.log2(len - 1)) + 1;
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const chunk = nextpower <= 256 ? 32 : nextpower / 8;
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return chunk * (Math.floor((len - 1) / chunk) + 1);
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},
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pad(unpadded) {
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const unpaddedB = utf8Encoder.encode(unpadded);
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const len = unpaddedB.length;
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if (len < 1 || len >= utils.v2.maxPlaintextSize)
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throw new Error("invalid plaintext length: must be between 1b and 64KB");
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const paddedLen = utils.v2.calcPadding(len);
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const zeros = new Uint8Array(paddedLen - len);
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const lenBuf = new Uint8Array(2);
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new DataView(lenBuf.buffer).setUint16(0, len);
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return concatBytes(lenBuf, unpaddedB, zeros);
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},
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unpad(padded) {
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const unpaddedLen = new DataView(padded.buffer).getUint16(0);
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const unpadded = padded.subarray(2, 2 + unpaddedLen);
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if (unpaddedLen === 0 || unpadded.length !== unpaddedLen || padded.length !== 2 + utils.v2.calcPadding(unpaddedLen))
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throw new Error("invalid padding");
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return utf8Decoder.decode(unpadded);
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}
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}
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};
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function encrypt(key, plaintext, options = {}) {
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const version = options.version ?? 2;
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if (version !== 2)
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throw new Error("unknown encryption version " + version);
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const salt = options.salt ?? randomBytes(32);
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ensureBytes(salt, 32);
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const keys = utils.v2.getMessageKeys(key, salt);
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const padded = utils.v2.pad(plaintext);
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const ciphertext = chacha20(keys.encryption, keys.nonce, padded);
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const mac = hmac(sha256, keys.auth, ciphertext);
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return base64.encode(concatBytes(new Uint8Array([version]), salt, ciphertext, mac));
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}
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function decrypt(key, ciphertext) {
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const u = utils.v2;
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ensureBytes(key, 32);
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const clen = ciphertext.length;
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if (clen < u.minCiphertextSize || clen >= u.maxCiphertextSize)
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throw new Error("invalid ciphertext length: " + clen);
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if (ciphertext[0] === "#")
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throw new Error("unknown encryption version");
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let data;
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try {
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data = base64.decode(ciphertext);
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} catch (error) {
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throw new Error("invalid base64: " + error.message);
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}
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const vers = data.subarray(0, 1)[0];
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if (vers !== 2)
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throw new Error("unknown encryption version " + vers);
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const salt = data.subarray(1, 33);
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const ciphertext_ = data.subarray(33, -32);
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const mac = data.subarray(-32);
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const keys = u.getMessageKeys(key, salt);
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const calculatedMac = hmac(sha256, keys.auth, ciphertext_);
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if (!equalBytes(calculatedMac, mac))
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throw new Error("invalid MAC");
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const padded = chacha20(keys.encryption, keys.nonce, ciphertext_);
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return u.unpad(padded);
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}
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export {
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decrypt,
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encrypt,
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utils
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};
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