Java Development

[#1]

Exercise

Build an API that will provide basic encryption and decryption using the Cryptography API through the use of a SymmetricKey.

Objectives

• Build how to create a SymmetricKey.
• Build how to use a SymmetricKey for encryption and decryption.
• Build how to use a Digest to provide data integrity.

Setup

1. Open BasicCryptoDeveloperLab_1.zip
2. In the IDE, open the BasicCryptoDeveloperLab.jdw workspace
3. Open the BasicCryptoDeveloperLab.java source file.

Tasks

1. Complete the implementation of the encrypt method:

   Create a new AES symmetric key using keyData.

   Create a new EncryptorEngine and FormatterEngine using the newly created key.

   Create a BlockEncryptor using the FormatterEngine.

   Create a new Digest (SHA-1) and hash the data using the digest.

   Encrypt the data and append the hash returning the ciphertext.

Complete the implementation of the decrypt method:

Create a new AES symmetric key using keyData.

Create a new DecryptorEngine and UnformatterEngine using the newly created key.

Create a BlockDecryptor using the UnformatterEngine.

Decrypt the data.

Create a new Digest (SHA-1) and hash the data using the digest.

Verify that the hash is correct and return the plaintext.

Note: You are required to import the net_rim_crypto.jar file into your project to access the Cryptography API.

Check Your Work

Check BasicCryptoDeveloperLab_2.zip

Review

In this exercise, you discovered the following things:

• to create a SymmetricKey and use it for encryption and decryption.
• to use a Digest to provide data integrity.