import parseKeys from "../parse_asn1/mod.js";import { randomBytes } from "../randombytes.ts";import { createHash } from "../../../internal/crypto/hash.ts";import mgf from "./mgf.js";import { xor } from "./xor.js";import { BN } from "../bn.js/bn.js";import { withPublic } from "./with_public.js";import crt from "../browserify_rsa.js";import { Buffer } from "../../../buffer.ts";
export function publicEncrypt(publicKey, msg, reverse) { let padding; if (publicKey.padding) { padding = publicKey.padding; } else if (reverse) { padding = 1; } else { padding = 4; } const key = parseKeys(publicKey); let paddedMsg; if (padding === 4) { paddedMsg = oaep(key, msg); } else if (padding === 1) { paddedMsg = pkcs1(key, msg, reverse); } else if (padding === 3) { paddedMsg = new BN(msg); if (paddedMsg.cmp(key.modulus) >= 0) { throw new Error("data too long for modulus"); } } else { throw new Error("unknown padding"); } if (reverse) { return crt(paddedMsg, key); } else { return withPublic(paddedMsg, key); }}
function oaep(key, msg) { const k = key.modulus.byteLength(); const mLen = msg.length; const iHash = createHash("sha1").update(Buffer.alloc(0)).digest(); const hLen = iHash.length; const hLen2 = 2 * hLen; if (mLen > k - hLen2 - 2) { throw new Error("message too long"); } const ps = Buffer.alloc(k - mLen - hLen2 - 2); const dblen = k - hLen - 1; const seed = randomBytes(hLen); const maskedDb = xor( Buffer.concat([iHash, ps, Buffer.alloc(1, 1), msg], dblen), mgf(seed, dblen), ); const maskedSeed = xor(seed, mgf(maskedDb, hLen)); return new BN(Buffer.concat([Buffer.alloc(1), maskedSeed, maskedDb], k));}function pkcs1(key, msg, reverse) { const mLen = msg.length; const k = key.modulus.byteLength(); if (mLen > k - 11) { throw new Error("message too long"); } let ps; if (reverse) { ps = Buffer.alloc(k - mLen - 3, 0xff); } else { ps = nonZero(k - mLen - 3); } return new BN( Buffer.concat([ Buffer.from([ 0, reverse ? 1 : 2, ]), ps, Buffer.alloc(1), msg, ], k), );}function nonZero(len) { const out = Buffer.allocUnsafe(len); let i = 0; let cache = randomBytes(len * 2); let cur = 0; let num; while (i < len) { if (cur === cache.length) { cache = randomBytes(len * 2); cur = 0; } num = cache[cur++]; if (num) { out[i++] = num; } } return out;}