rsa.js

/* eslint-disable */

// Depends on jsbn.js and rng.js

// Version 1.1: support utf-8 encoding in pkcs1pad2

import './jsbn';
import './rng';
import './base64';

const stringToUtf8ByteArray = (str) => {
  // TODO(user): Use native implementations if/when available
  const out = [];
  let p = 0;
  for (let i = 0; i < str.length; i++) {
    let c = str.charCodeAt(i);
    if (c < 128) {
      out[p++] = c;
    } else if (c < 2048) {
      out[p++] = (c >> 6) | 192;
      out[p++] = (c & 63) | 128;
    } else if (
      ((c & 0xFC00) === 0xD800) && (i + 1) < str.length &&
      ((str.charCodeAt(i + 1) & 0xFC00) === 0xDC00)) {
      // Surrogate Pair
      c = 0x10000 + ((c & 0x03FF) << 10) + (str.charCodeAt(++i) & 0x03FF);
      out[p++] = (c >> 18) | 240;
      out[p++] = ((c >> 12) & 63) | 128;
      out[p++] = ((c >> 6) & 63) | 128;
      out[p++] = (c & 63) | 128;
    } else {
      out[p++] = (c >> 12) | 224;
      out[p++] = ((c >> 6) & 63) | 128;
      out[p++] = (c & 63) | 128;
    }
  }
  return out;
};

// convert a (hex) string to a bignum object
function parseBigInt(str,r) {
  return new BigInteger(str,r);
}

function linebrk(s,n) {
  var ret = "";
  var i = 0;
  while(i + n < s.length) {
    ret += s.substring(i,i+n) + "\n";
    i += n;
  }
  return ret + s.substring(i,s.length);
}

function byte2Hex(b) {
  if(b < 0x10)
    return "0" + b.toString(16);
  else
    return b.toString(16);
}

function str2blocks(s, n) {
  const bytes = stringToUtf8ByteArray(s);
  const blocks = [];
  const blockSize = n - 11;
  for (let i = 1; i * blockSize < bytes.length; ++i) {
    blocks.push(pkcs1pad(bytes.slice((i - 1) * blockSize, i * blockSize), n));
  }
  return blocks;
}

function pkcs1pad(block, n) {
  const out = block;
  out.push(0);
  const rng = new SecureRandom();
  const x = [];
  const rSize = n - out.length - 3;
  for (let i = 0; i < rSize; ++i) {
    x[0] = 0;
    while(x[0] === 0) rng.nextBytes(x);
    out.push(x[0]);
  }
  out.push(2);
  out.push(0);
  return new BigInteger(out);
}

// PKCS#1 (type 2, random) pad input string s to n bytes, and return a bigint
function pkcs1pad2(s,n) {
  if(n < s.length + 11) { // TODO: fix for utf-8
    alert("Message too long for RSA");
    return null;
  }
  var ba = new Array();
  var i = s.length - 1;
  while(i >= 0 && n > 0) {
    var c = s.charCodeAt(i--);
    if(c < 128) { // encode using utf-8
      ba[--n] = c;
    }
    else if((c > 127) && (c < 2048)) {
      ba[--n] = (c & 63) | 128;
      ba[--n] = (c >> 6) | 192;
    }
    else {
      ba[--n] = (c & 63) | 128;
      ba[--n] = ((c >> 6) & 63) | 128;
      ba[--n] = (c >> 12) | 224;
    }
  }
  ba[--n] = 0;
  var rng = new SecureRandom();
  var x = new Array();
  while(n > 2) { // random non-zero pad
    x[0] = 0;
    while(x[0] == 0) rng.nextBytes(x);
    ba[--n] = x[0];
  }
  ba[--n] = 2;
  ba[--n] = 0;
  return new BigInteger(ba);
}

// "empty" RSA key constructor
function RSAKey() {
  this.n = null;
  this.e = 0;
  this.d = null;
  this.p = null;
  this.q = null;
  this.dmp1 = null;
  this.dmq1 = null;
  this.coeff = null;
}

// Set the public key fields N and e from hex strings
function RSASetPublic(N,E) {
  if(N != null && E != null && N.length > 0 && E.length > 0) {
    this.n = parseBigInt(N,16);
    this.e = parseInt(E,16);
  }
  else
    alert("Invalid RSA public key");
}

// Perform raw public operation on "x": return x^e (mod n)
function RSADoPublic(x) {
  return x.modPowInt(this.e, this.n);
}

// Return the PKCS#1 RSA encryption of "text" as an even-length hex string
function RSAEncrypt(text) {
  var m = pkcs1pad2(text,(this.n.bitLength()+7)>>3);
  if(m == null) return null;
  var c = this.doPublic(m);
  if(c == null) return null;
  var h = c.toString(16);
  if((h.length & 1) == 0) return h; else return "0" + h;
}

function RSAEncryptLongText(text) {
  const blocks = str2blocks(text, (this.n.bitLength()+7)>>3);
  const out = [];
  for (let i = 0; i < blocks.length; ++ i) {
    const c = this.doPublic(blocks[i]);
    if (c == null) return null;
    const h = c.toString(16);
    if ((h.length & 1) === 0) {
      out.push(h);
    } else {
      out.push(`0${h}`);
    }
  }
  return out.join('');
}

// Return the PKCS#1 RSA encryption of "text" as a Base64-encoded string
//function RSAEncryptB64(text) {
//  var h = this.encrypt(text);
//  if(h) return hex2b64(h); else return null;
//}

// protected
RSAKey.prototype.doPublic = RSADoPublic;

// public
RSAKey.prototype.setPublic = RSASetPublic;
RSAKey.prototype.encrypt = RSAEncrypt;
RSAKey.prototype.encryptLong = RSAEncryptLongText;
//RSAKey.prototype.encrypt_b64 = RSAEncryptB64;

export default RSAKey;