Module dev.netcode.security

Package dev.netcode.security.encryption

Class RSAEncrypter

java.lang.Object

dev.netcode.security.encryption.RSAEncrypter

public class RSAEncrypter
extends java.lang.Object

This class simplifies the process of RSA Encrypting data. Using it you can generate RSA Keys and encrypt/decrypt data.

Constructor Summary

Constructors

Constructor	Description
RSAEncrypter()

Method Summary

Modifier and Type	Method	Description
static java.lang.String	decrypt(byte[] cipher, java.security.PrivateKey privateKey)	Decrypts RSA encrypted data
static byte[]	encrypt(java.lang.String message, java.security.PublicKey publicKey)	Encrypts a message using a RSA PublicKey
static java.security.KeyPair	generateKeyPair(int size)	Generates a KeyPair with given size.
static java.security.PrivateKey	generatePrivateKeyFromString(byte[] key)	Generates a private key from byte array
static java.security.PublicKey	generatePublicKeyFromString(byte[] key)	Generates a public key from byte array
static java.lang.String	getFingerprint(java.security.PublicKey key)	Generates a fingerprint string of a public key.
static java.lang.String	keyToString(java.security.Key key)	Encodes a Key to a String representation.
static java.lang.String	sign(java.security.PrivateKey privateKey, java.lang.String input)	Generates a RSA signature for a given input.
static boolean	verifySignature(java.security.PublicKey publicKey, java.lang.String data, java.lang.String signature)	Verifies that a given signature matches given data and a given public key.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RSAEncrypter

public RSAEncrypter()

Method Detail

generateKeyPair

public static java.security.KeyPair generateKeyPair(int size)

Generates a KeyPair with given size. The higher the size, the more secure the key can be considered. Size must be divisible by 2.

Parameters:

size - of the keys to be generated

Returns:

the generated KeyPair

decrypt

public static java.lang.String decrypt(byte[] cipher,
                                       java.security.PrivateKey privateKey)
                                throws java.security.InvalidKeyException,
                                       javax.crypto.IllegalBlockSizeException,
                                       javax.crypto.BadPaddingException

Decrypts RSA encrypted data

Parameters:

cipher - data to be decrypted

privateKey - to be used to decrypt the data

Returns:

decrypted data as UTF-8 encoded String

Throws:

java.security.InvalidKeyException - in case the key format is not supported

javax.crypto.BadPaddingException - in case something failed while padding

javax.crypto.IllegalBlockSizeException - in case the blocksize is invalid

encrypt

public static byte[] encrypt(java.lang.String message,
                             java.security.PublicKey publicKey)
                      throws java.security.InvalidKeyException,
                             javax.crypto.IllegalBlockSizeException,
                             javax.crypto.BadPaddingException

Encrypts a message using a RSA PublicKey

Parameters:

message - to be encrypted

publicKey - ised to encrypt the data

Returns:

byte array of encrypted data

Throws:

java.security.InvalidKeyException - in case the key format is not supported

javax.crypto.BadPaddingException - in case something failed while padding

javax.crypto.IllegalBlockSizeException - in case the blocksize is invalid

sign

public static java.lang.String sign(java.security.PrivateKey privateKey,
                                    java.lang.String input)
                             throws java.security.InvalidKeyException,
                                    java.security.SignatureException

Generates a RSA signature for a given input. The signature can be used to make sure a message comes from a specific sender

Parameters:

privateKey - used to sign the data

input - data to be signed

Returns:

Signature as String

Throws:

java.security.InvalidKeyException - in case the key format is not supported

java.security.SignatureException - in case something went wrong while creating the signature

verifySignature

public static boolean verifySignature(java.security.PublicKey publicKey,
                                      java.lang.String data,
                                      java.lang.String signature)

Verifies that a given signature matches given data and a given public key. This process ensures that the data really comes from the sender

Parameters:

publicKey - of the sender

data - original data

signature - to be tested

Returns:

true if the signature matches the data and public key

generatePublicKeyFromString

public static java.security.PublicKey generatePublicKeyFromString(byte[] key)
                                                           throws java.security.spec.InvalidKeySpecException

Generates a public key from byte array

Parameters:

key - byte array

Returns:

public key

Throws:

java.security.spec.InvalidKeySpecException - in case the key format is not supported

generatePrivateKeyFromString

public static java.security.PrivateKey generatePrivateKeyFromString(byte[] key)
                                                             throws java.security.spec.InvalidKeySpecException

Generates a private key from byte array

Parameters:

key - byte array

Returns:

private key

Throws:

java.security.spec.InvalidKeySpecException - in case the key format is not supported

keyToString

public static java.lang.String keyToString(java.security.Key key)

Encodes a Key to a String representation. The key will be encoded to Base64

Parameters:

key - to transform

Returns:

String representation

getFingerprint

public static java.lang.String getFingerprint(java.security.PublicKey key)

Generates a fingerprint string of a public key. The key has to be X509 compatible. The fingerprint will be SHA-1 representation of the key

Parameters:

key - to get the fingerprint of

Returns:

the fingerprint