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build/node_modules/public-encrypt/publicEncrypt.js

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+var parseKeys = require('parse-asn1');
+var randomBytes = require('randombytes');
+var createHash = require('create-hash');
+var mgf = require('./mgf');
+var xor = require('./xor');
+var bn = require('bn.js');
+var withPublic = require('./withPublic');
+var crt = require('browserify-rsa');
+
+var constants = {
+  RSA_PKCS1_OAEP_PADDING: 4,
+  RSA_PKCS1_PADDIN: 1,
+  RSA_NO_PADDING: 3
+};
+
+module.exports = function publicEncrypt(public_key, msg, reverse) {
+  var padding;
+  if (public_key.padding) {
+    padding = public_key.padding;
+  } else if (reverse) {
+    padding = 1;
+  } else {
+    padding = 4;
+  }
+  var key = parseKeys(public_key);
+  var 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){
+  var k = key.modulus.byteLength();
+  var mLen = msg.length;
+  var iHash = createHash('sha1').update(new Buffer('')).digest();
+  var hLen = iHash.length;
+  var hLen2 = 2 * hLen;
+  if (mLen > k - hLen2 - 2) {
+    throw new Error('message too long');
+  }
+  var ps = new Buffer(k - mLen - hLen2 - 2);
+  ps.fill(0);
+  var dblen = k - hLen - 1;
+  var seed = randomBytes(hLen);
+  var maskedDb = xor(Buffer.concat([iHash, ps, new Buffer([1]), msg], dblen), mgf(seed, dblen));
+  var maskedSeed = xor(seed, mgf(maskedDb, hLen));
+  return new bn(Buffer.concat([new Buffer([0]), maskedSeed, maskedDb], k));
+}
+function pkcs1(key, msg, reverse){
+  var mLen = msg.length;
+  var k = key.modulus.byteLength();
+  if (mLen > k - 11) {
+    throw new Error('message too long');
+  }
+  var ps;
+  if (reverse) {
+    ps = new Buffer(k - mLen - 3);
+    ps.fill(0xff);
+  } else {
+    ps = nonZero(k - mLen - 3);
+  }
+  return new bn(Buffer.concat([new Buffer([0, reverse?1:2]), ps, new Buffer([0]), msg], k));
+}
+function nonZero(len, crypto) {
+  var out = new Buffer(len);
+  var i = 0;
+  var cache = randomBytes(len*2);
+  var cur = 0;
+  var num;
+  while (i < len) {
+    if (cur === cache.length) {
+      cache = randomBytes(len*2);
+      cur = 0;
+    }
+    num = cache[cur++];
+    if (num) {
+      out[i++] = num;
+    }
+  }
+  return out;
+}