Java-Crypto-Utils
Well some families asked for a good API to use Java Crypto in their project. In record time, we delivered.
Compilation and Installation
The easy way to do this is by using maven and simply running the below command.
mvn install
Now you can edit your project's POM and add the following dependency:
<groupId>pt.ulisboa.tecnico.meic.sec</groupId>
<artifactId>crypto</artifactId>
<version>1.1</version>
You are now ready to use one of the best API out there 😄
Usage
You only need to instantiate an object of the class CryptoManager.
CryptoManager cryptoManager = new CryptoManager();
After instantiate, you can call all the methods shown below on the object.
Also, some utility functions are available statically at CryptoUtilities class.
Demo
A complete demonstration can be found in the Application class.
API Reference
CryptoManager Class
| Method | What it does | Parameters | Returns |
|---|---|---|---|
| generateNounce | Generates a Nounce with the size given | (int bytes) | byte[] |
| getActualTimestamp | Returns the Actual Time Timestamp | (void) | java.sql.Timestamp |
| isTimestampAndNonceValid | Checks if the Timestamp is fresh and if the pair Timestamp, Nonce was already seen. | (Timestamp date, byte[] nounce) | boolean |
| convertBinaryToBase64 | Binary -> Base64 | (byte[] data) | String |
| convertBase64ToBinary | Base64 -> Binary | (String data) | byte[] |
| digest | SHA-2(toBeDigested) | (byte[] toBeDigested) | byte[] |
| getPublicKeyFingerprint | SHA-2(publicKey) | (PublicKey publicKey) | byte[] |
| makeDigitalSignature | Signature(SHA-2(toBeDigested)) | (byte[] bytesToSign, KeyPair keyPair) | byte[] |
| verifyDigitalSignature | Checks if the signature is valid. | (byte[] signedDigest, byte[] bytesToBeVerified, PublicKey publicKey) | boolean |
| runAES | Encrypts/Decrypts using AES-CBC Algorithm | (byte[] bytesToEncrypt, Key aesKey, byte[] iv, int mode)* | byte[] |
| generateIV | Generates a Secure Random IV | (int bytes) | byte[] |
| generateAESKey | Generates an AES Key | (int bits) | Key |
| signFields | Signs the concatenated content of the String[] | (String[] fieldsToSign, KeyStore keyStore, String keyAlias, char[] keyPassword) | byte[] |
| isValidSig | Checks if the concatenation of the String[] is properly authenticated | (PublicKey publicKey, String[] fieldsToCheck, String signatureSent) | boolean |
*mode can be Cipher.ENCRYPT_MODE to encrypt, or Cipher.DECRYPT_MODE to decrypt
CryptoUtilities Class
Note that all methods below are static.
| Method | What it does | Parameters | Returns |
|---|---|---|---|
| getPrivateKeyFromKeystore | Retrieves the PrivateKey from the given KeyStore | (KeyStore keystore, String keyAlias, char[] keyPassword) | PrivateKey |
| getPublicKeyFromKeystore | Retrieves the PublicKey from the given KeyStore | (KeyStore keystore, String keyAlias, char[] keyPassword) | PublicKey |
| readKeystoreFile | Loads into memory a KeyStore that is written to a file | (String keyStoreFilePath, char[] keyStorePassword) | KeyStore |
| readAESKey | Loads into memory an AES key that is written to a file | (String keyPath) | Key |
| writeAESKey | Writes into disk an AES key | (String keyPath, Key symmetricKey) | void |
Acknowledgments
I thank my pet Nicky that didn't allow me to have a full hour of work on this library.