browserify-aes/EVP_BytesToKey.js

var md5 = require('create-hash/md5')
module.exports = EVP_BytesToKey
function EVP_BytesToKey (password, keyLen, ivLen) {
  if (!Buffer.isBuffer(password)) {
    password = new Buffer(password, 'binary')
  }
  keyLen = keyLen / 8
  ivLen = ivLen || 0
  var ki = 0
  var ii = 0
  var key = new Buffer(keyLen)
  var iv = new Buffer(ivLen)
  var addmd = 0
  var md_buf
  var i
  var bufs = []
  while (true) {
    if (addmd++ > 0) {
      bufs.push(md_buf)
    }
    bufs.push(password)
    md_buf = md5(Buffer.concat(bufs))
    bufs = []
    i = 0
    if (keyLen > 0) {
      while (true) {
        if (keyLen === 0) {
          break
        }
        if (i === md_buf.length) {
          break
        }
        key[ki++] = md_buf[i]
        keyLen--
        i++
      }
    }
    if (ivLen > 0 && i !== md_buf.length) {
      while (true) {
        if (ivLen === 0) {
          break
        }
        if (i === md_buf.length) {
          break
        }
        iv[ii++] = md_buf[i]
        ivLen--
        i++
      }
    }
    if (keyLen === 0 && ivLen === 0) {
      break
    }
  }
  for (i = 0; i < md_buf.length; i++) {
    md_buf[i] = 0
  }
  return {
    key: key,
    iv: iv
  }
}