code: function pkcs1unpad2(d,n) {
    var b = d.toByteArray();
    var i = 0;
    while(i < b.length && b[i] == 0) ++i;
    if(b.length-i != n-1 || b[i] != 2)
      return null;
    ++i;
    while(b[i] != 0)
      if(++i >= b.length) return null;
    var ret = "";
    while(++i < b.length)
      ret += String.fromCharCode(b[i]);
    return ret;
  }
docs: RSAKey.prototype.encrypt_b64 = RSAEncryptB64; Depends on rsa.js and jsbn2.js Undo PKCS#1 (type 2, random) padding and, if valid, return the plaintext