---

By Alx: December 2019

---

Encrypt and decrypt data with RSA

Goal

This article explains how to generate a RSA Keypair in order to encrypt and decrypt data.

Big picture

Used technologies

JDK 1.8
Maven 3.2

Maven dependencies

There is only one dependency:junit

Helper class

Details:
In order to create a KeyPairGenerator you have to specify a algorithm RSA
We initialize the KeyPairGenerator by passing a keysize, we choose 2048 bit
At (line 10) we generate KeyPair that contains Public and Private Key

The encryptmethod takes two parameter: the Public Key and the message that should be enrcypted
After creating a RSA cipher,we initialize the Cipher with mode=ENCRYPT_MODE and pass the message
The method doFinal()performs Encryption and returns a byte array of the encrypted message

The decryptmethod takes two parameter: the Private Key and the encrypted message
For cipher initialization you specify the DECRYPT_MODE

Test class

Run the test

The output should look like:

References

• KeyPairGenerator
• RSA (cryptosystem)

• security