de.upb.swtpra05.group03.crypto
Class Crypto

java.lang.Object
  de.upb.swtpra05.group03.crypto.Crypto

Direct Known Subclasses:

AliceCrypto, BobCrypto

public abstract class Crypto

extends java.lang.Object

This is the main Crypto class. It is used to encrypt and decrypt messages.

Version:

$Revision: 1.3 $

Field Summary

protected static java.lang.String	AGREEMENT_ALGORITHM Algorithm used for public/private key agreement
protected static java.lang.String	CIPHER_ALGORITHM Algorithm used for symmetric en-/decryption
private javax.crypto.Cipher	decrypter Cipher object used for decryption
private javax.crypto.Cipher	encrypter Cipher object used for encryption
protected static java.lang.String	KEY_ALGORITHM Algorithm used to create the secret key
protected java.security.KeyFactory	pubKeyFactory factory used to create public keys from x509 encoding
private javax.crypto.SecretKey	secretKey secret key with which data is en-/decrypted
protected static java.lang.String	SIGNATURE_ALGORITHM Algorithm used for signing and verifying data
protected java.security.Signature	signer Signature object used for signing
protected int	state holds the state of this object
static int	STATE_INIT Constant for State INIT
static int	STATE_READY Constant for State READY
static int	STATE_WAITING Constant for State WAITING
protected java.security.Signature	verifyer Signature object used for verifying signatures

Constructor Summary

Crypto()
Constructor to create the Crypto object.

Method Summary

java.lang.Object	decryptObject(DataSigPair dsp) decrypts an bytearray to an object
DataSigPair	encryptObject(java.io.Serializable obj) encrypts an object
protected java.security.PublicKey	genPublicKeyFromX509(byte[] x509Key) generates a public key from the bytearray in the x509 format
byte[]	getSecretKey() gets the secret key
boolean	isReady() if state is READY
protected void	loadSigningKeys(java.lang.String name) loads public and private key with the SigningKeys class.
void	reset() reset the state to INIT so a new key agreement can be made
void	setSecretKey(byte[] key) to set the secret key directly without key agreement
protected void	setSecretKey(javax.crypto.SecretKey secretKey) sets the secret key directly without key agreement
protected byte[]	sign(byte[] data) signs data
protected boolean	verify(DataSigPair dsp) verifies signature for data

Methods inherited from class java.lang.Object

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

Field Detail

STATE_INIT

public static final int STATE_INIT

Constant for State INIT

See Also:

Constant Field Values

STATE_WAITING

public static final int STATE_WAITING

Constant for State WAITING

See Also:

Constant Field Values

STATE_READY

public static final int STATE_READY

Constant for State READY

See Also:

Constant Field Values

AGREEMENT_ALGORITHM

protected static final java.lang.String AGREEMENT_ALGORITHM

Algorithm used for public/private key agreement

See Also:

Constant Field Values

KEY_ALGORITHM

protected static final java.lang.String KEY_ALGORITHM

Algorithm used to create the secret key

See Also:

Constant Field Values

CIPHER_ALGORITHM

protected static final java.lang.String CIPHER_ALGORITHM

Algorithm used for symmetric en-/decryption

See Also:

Constant Field Values

SIGNATURE_ALGORITHM

protected static final java.lang.String SIGNATURE_ALGORITHM

Algorithm used for signing and verifying data

See Also:

Constant Field Values

state

protected int state

holds the state of this object

secretKey

private javax.crypto.SecretKey secretKey

secret key with which data is en-/decrypted

encrypter

private final javax.crypto.Cipher encrypter

Cipher object used for encryption

decrypter

private final javax.crypto.Cipher decrypter

Cipher object used for decryption

signer

protected final java.security.Signature signer

Signature object used for signing

verifyer

protected final java.security.Signature verifyer

Signature object used for verifying signatures

pubKeyFactory

protected final java.security.KeyFactory pubKeyFactory

factory used to create public keys from x509 encoding

Constructor Detail

Crypto

public Crypto()
       throws java.security.NoSuchAlgorithmException,
              javax.crypto.NoSuchPaddingException

Constructor to create the Crypto object.

Throws:

javax.crypto.NoSuchPaddingException

java.security.NoSuchAlgorithmException

Method Detail

loadSigningKeys

protected void loadSigningKeys(java.lang.String name)
                        throws java.security.NoSuchAlgorithmException,
                               java.security.spec.InvalidKeySpecException,
                               java.io.IOException,
                               java.security.InvalidKeyException

loads public and private key with the SigningKeys class. the public key is used by the verifyer and the secret one is used by the signer

Parameters:

name - have to be either "shuttle" or "company"

Throws:

java.security.NoSuchAlgorithmException

java.security.spec.InvalidKeySpecException

java.io.IOException

java.security.InvalidKeyException

See Also:

SigningKeys.loadKeys(String)

setSecretKey

public void setSecretKey(byte[] key)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException,
                         java.security.InvalidKeyException

to set the secret key directly without key agreement

Parameters:

key - a bytearray of the serialized SecretKey object

Throws:

java.io.IOException

java.lang.ClassNotFoundException

java.security.InvalidKeyException

setSecretKey

protected void setSecretKey(javax.crypto.SecretKey secretKey)
                     throws java.security.InvalidKeyException

sets the secret key directly without key agreement

Parameters:

secretKey - the new SecretKey

Throws:

java.security.InvalidKeyException

getSecretKey

public byte[] getSecretKey()
                    throws java.io.IOException

gets the secret key

Returns:

secret key serialized as a bytearray

Throws:

java.io.IOException

reset

public void reset()

reset the state to INIT so a new key agreement can be made

encryptObject

public DataSigPair encryptObject(java.io.Serializable obj)
                          throws java.io.IOException,
                                 java.security.SignatureException

encrypts an object

Parameters:

obj - object wich implements Serializable

Returns:

encrypted object and the coresponding signature

Throws:

java.io.IOException

java.security.SignatureException

java.security.SignatureException

decryptObject

public java.lang.Object decryptObject(DataSigPair dsp)
                               throws java.lang.IllegalStateException,
                                      java.io.IOException,
                                      java.lang.ClassNotFoundException,
                                      java.security.SignatureException

decrypts an bytearray to an object

Parameters:

dsp - object containing data and signature

Returns:

decrypted object

Throws:

java.lang.IllegalStateException

java.io.IOException

java.lang.ClassNotFoundException

java.security.SignatureException

sign

protected byte[] sign(byte[] data)
               throws java.security.SignatureException

signs data

Parameters:

data - a bytearray

Returns:

signature for data

Throws:

java.security.SignatureException

verify

protected boolean verify(DataSigPair dsp)
                  throws java.security.SignatureException

verifies signature for data

Parameters:

dsp - object containing data and signature

Returns:

true if the signature was verified, false if not.

Throws:

java.security.SignatureException

isReady

public boolean isReady()

if state is READY

Returns:

if state is READY

genPublicKeyFromX509

protected java.security.PublicKey genPublicKeyFromX509(byte[] x509Key)
                                                throws java.security.spec.InvalidKeySpecException

generates a public key from the bytearray in the x509 format

Parameters:

x509Key - public key in the x509 format

Returns:

public key decoded from the x509 format

Throws:

java.security.spec.InvalidKeySpecException