rsa_encrypt 1.0.3

RSA encryption package.

Getting Started

RSA keys generator, String encryption and decryption and String signing.

How it works

let say Alice want to send a message to Bob. a normal messaging solution would be : Alice write the message and send it to Bob the only problem is that the Message will be transferred in PlainText and every one who intercept the message can read it.

This is were RSA comes to play:

  1. We generate keys( public & private ) for Bob.

  2. If Alice wanted to send a message to Bob she have to encrypt that message with Bob's public keys.

  3. Then the encrypted message will be transferred to Bob and only Bob's private key can decrypt that message.

that way no none can decrypt the message except the owner of that specific private key.

How to use

in order to use RSA encryption you need to generate 2 keys a public key (used to encrypt a text) and a private key (used to decrypt a text).

Those are the functions and header needed:

import 'package:rsa_encrypt/rsa_encrypt.dart';
import 'package:pointycastle/api.dart' as crypto;

//Future to hold our KeyPair
Future<crypto.AsymmetricKeyPair> futureKeyPair;

//to store the KeyPair once we get data from our future
crypto.AsymmetricKeyPair keyPair;

Future<crypto.AsymmetricKeyPair<crypto.PublicKey, crypto.PrivateKey>> getKeyPair()
{
var helper = RsaKeyHelper();
return helper.computeRSAKeyPair(helper.getSecureRandom());
}
  1. Generate KeyPair with the function getKeyPair() store the returned value in futureKeyPair.
  2. Once we get data from the future we can store that data in keyPair (Now we have acces to our private and public key).
  3. In order to view our keys as "a string" we need to use two functions encodePrivateKeyToPemPKCS1(keyPair.privateKey) & encodePublicKeyToPemPKCS1(keyPair.publicKey).
  4. In order to encrypt and decrypt strings you can use two functions
  • encrypt() : use this function to encrypt a string, pass your string as first argument and a public key as the second one. IMPORTANT: this will return a string so you should store the returned value in a variable.
  • decrypt() : use this function to decrypt an encrypted String, pass your encrypted String as first argument and a private key as the second. this will also return a string dont forget to store it :) .

A youtube video will be available soon!

More on RSA

The RSA Encryption Algorithm (1 of 2: Computing an Example)

The RSA Encryption Algorithm (2 of 2: Generating the Keys)

How to solve RSA Algorithm Problems?


depends on pointycastle, asn1lib.

thanks to Gonçalo Palma for his Article.


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Libraries

rsa_encrypt

Dart

VM

dart:ffi
Foreign Function Interface for interoperability with the C programming language. [...]

Web

dart:html
HTML elements and other resources for web-based applications that need to interact with the browser and the DOM (Document Object Model). [...]
dart:js
Low-level support for interoperating with JavaScript. [...]
dart:js_util
Utility methods to efficiently manipulate typed JSInterop objects in cases where the name to call is not known at runtime. You should only use these methods when the same effect cannot be achieved with @JS annotations. These methods would be extension methods on JSObject if Dart supported extension methods.