info.pppc.base.security.key

Class RSAPublicKey

java.lang.Object

info.pppc.base.security.key.RSAPublicKey

All Implemented Interfaces:

IPublicKey

public class RSAPublicKey
extends java.lang.Object
implements IPublicKey

Here Input and OutputStreams could be used, but a new Thread would be necessary, because the use of the PipeStream (is not available for j2me). Implements a RSA public key, which can be used for encryption of messages and verification of signatures. If the message exceeds the key size (usually 1024 bits), than hybrid encryption is used. First a symmetric AES key is encrypted with this RSA public key and then the message is encrypted using AES-CBC.

Author:

WA

Field Summary

Fields

Modifier and Type	Field and Description
static int	PRE_HEADER_LENGTH

Constructor Summary

Constructors

Constructor and Description
RSAPublicKey(java.security.cert.X509Certificate cert) Creates a new RSAPublicKey with the given rsa key parameters and uses an AES key of 128 bit size (for hybrid encryption).
RSAPublicKey(java.security.cert.X509Certificate cert, int aesKeySize) Creates a new RSAPublicKey with the given rsa key parameters and uses the given key size for the AES key (hybrid encryption).

Method Summary

Methods

Modifier and Type	Method and Description
byte[]	encryptMessage(byte[] input) Encrypts a message using this RSA public key.
boolean	equals(java.lang.Object obj) Every public key has to implement a comparison operator.
boolean	verifySignature(byte[] message, byte[] signature) Use this public key to verify a signature.

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PRE_HEADER_LENGTH

public static final int PRE_HEADER_LENGTH

See Also:

Constant Field Values

Constructor Detail

RSAPublicKey

public RSAPublicKey(java.security.cert.X509Certificate cert,
            int aesKeySize)

Creates a new RSAPublicKey with the given rsa key parameters and uses the given key size for the AES key (hybrid encryption). The key size must be 128, 192 or 256 bits.

Parameters:

keyParameters - An RSA public key

aesKeySize - The AES key size, can be 128, 192 or 256 bits

RSAPublicKey

public RSAPublicKey(java.security.cert.X509Certificate cert)

Creates a new RSAPublicKey with the given rsa key parameters and uses an AES key of 128 bit size (for hybrid encryption).

Parameters:

keyParameters - An RSA public key

Method Detail

encryptMessage

public byte[] encryptMessage(byte[] input)
                      throws java.io.IOException

Encrypts a message using this RSA public key.
Uses Hybrid encryption, if the input length exceeds the block size, then AES is used! Returns a header: The first 3 Byte are RSA or AES. For RSA now the encrypted parts start, for AES, the key is added, so the AES-header is:
AES<KeySize><Key><InitializationVector><EncryptedPart>
For example: AES128THEAESKEY...THEINITIALIZATIONVECTOR...THEENCRYPTEDPART...

Specified by:

encryptMessage in interface IPublicKey

Parameters:

input - The message which should be encrypted

Returns:

An encrypted message containing the header which is described above

Throws:

java.io.IOException - If not enough memory is available or if a key could not be read, this exception occurs

verifySignature

public boolean verifySignature(byte[] message,
                      byte[] signature)

Description copied from interface: IPublicKey

Use this public key to verify a signature.

Specified by:

verifySignature in interface IPublicKey

Parameters:

message - The message which was signed

signature - The signature of this message

Returns:

True, if the signature is valid, false otherwise

equals

public boolean equals(java.lang.Object obj)

Description copied from interface: IPublicKey

Every public key has to implement a comparison operator. Usually an public key equals another one, if the key is identical. This method must returns true, if the public keys equal each other.

Specified by:

equals in interface IPublicKey

Overrides:

equals in class java.lang.Object

Parameters:

obj - The object of the type AbstractCertificate that should be compared to the current public key

Returns:

True, if the current public key and the given public key are equal, false otherwise

See Also:

Object.equals(java.lang.Object)