iaik.security.cipher
Class RC5Parameters

java.lang.Object
  |
  +--java.security.AlgorithmParametersSpi
        |
        +--iaik.security.cipher.IvParameters
              |
              +--iaik.security.cipher.RC5Parameters

public class RC5Parameters

extends IvParameters

This class represents RC5 paramters in opaque form and may be used for generating opaque RC5 parameters and converting them between various formats.

The parameters specified for the RC5 algorithm in RFC2040 specify the version number, the number of rounds, the word size (block size in bits) and an optional initialization vector:

 RC5-CBCParameters :: SEQUENCE {
   version          INTEGER (v1_0(16)),
   rounds           INTEGER (8..127),
   blockSizeInBits  INETGER (64, 128),
   iv               OCTET STRING OPTIONAL
 }
 

RC5Paramters may be generated provider independently by calling one of the AlgorithmParameters.getInstance methods for the algorithm in mind. Subsequently the new AlgorithmParamters object must be initialized with a proper RC5 parameter specification or a DER encoded byte array. If the first way is chosen, the parameter values (version, rounds, wordsize, and IV, if present) for initializing the new AlgorithmParameters object immediately are taken from the given RC5 parameter specification; if the parameters are given as DER encoded byte array, the values are parsed from the derived ASN.1 object, e.g.:

 RC5ParameterSpec rc5ParmSpec = ...;
 AlgorithmParameters params = AlgorithmParameters.getInstance("RC5", "IAIK");
 params.init(rc5ParamsSpec);
 

For obtaining RC5 parameters in transparent representation from an opaque RC5Paramters object, the getParameterSpec method can be used; for obtaining the parameters as DER encoded ASN.1 object, use getEncoded.

Please notice, that this implementation only allows a wordsize of 32 bit, i.e. 64 bit blocksize. The iv needs to be eight octets long, too.

Version:

File Revision 10

Constructor Summary

RC5Parameters()
The default constructor.

Method Summary

protected byte[]	engineGetEncoded() Returns the parameters as DER byte array.
protected byte[]	engineGetEncoded(String format) Returns the parameters as a DER byte array.
protected AlgorithmParameterSpec	engineGetParameterSpec(Class paramSpec) Returns the RC5 parameters as transparent RC5 parameter specification of the given class type.
protected void	engineInit(AlgorithmParameterSpec paramSpec) Initializes this RC5Parameters with the RC5 parameter values from a given RC5ParameterSpec.
protected void	engineInit(byte[] params) Initializes this RC5Parameters object from the given DER encoded byte array.
protected void	engineInit(byte[] params, String format) Inits the parameters from an DER encoded byte array.
protected String	engineToString() Returns a String representation of the parameters.

Methods inherited from class java.lang.Object

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

Constructor Detail

RC5Parameters

public RC5Parameters()

The default constructor. Only internally used for creating a RC5Parameters object. Applications shall use one of the AlgorithmParameters.getInstance factory methods for obtaining RC5Parameters.

Method Detail

engineGetEncoded

protected byte[] engineGetEncoded()
                           throws IOException

Returns the parameters as DER byte array.

Overrides:

engineGetEncoded in class IvParameters

Returns:

the RC5 parameters as DER byte array

Throws:

IOException - if an encoding error occurs

engineGetEncoded

protected byte[] engineGetEncoded(String format)
                           throws IOException

Returns the parameters as a DER byte array.

Format is ignored. Only DER encoding is supported at this time. This method only calls engineGetEncoded(), regardless of what is specified in the format string.

Overrides:

engineGetEncoded in class IvParameters

Parameters:

format - the encoding format; ignored

Returns:

the RC5 parameters as DER byte array

Throws:

IOException - if an encoding error occurs

engineGetParameterSpec

protected AlgorithmParameterSpec engineGetParameterSpec(Class paramSpec)
                                                 throws InvalidParameterSpecException

Returns the RC5 parameters as transparent RC5 parameter specification of the given class type.

Overrides:

engineGetParameterSpec in class IvParameters

Parameters:

paramSpec - the desired parameter specification class (RC5ParameterSpec)

Returns:

the parameters as RC5ParameterSpec

Throws:

InvalidParameterSpecException - if the paramters cannot be converted to the desired parameter specification

engineInit

protected void engineInit(AlgorithmParameterSpec paramSpec)
                   throws InvalidParameterSpecException

Initializes this RC5Parameters with the RC5 parameter values from a given RC5ParameterSpec.

Overrides:

engineInit in class IvParameters

Parameters:

paramSpec - the parameter specification, which has to be a RC5ParameterSpec

Throws:

InvalidParameterSpecException - if the given parameter specification is not a RC5ParameterSpec or the included parameters are invalid

engineInit

protected void engineInit(byte[] params)
                   throws IOException

Initializes this RC5Parameters object from the given DER encoded byte array.

From the given byte array an ASN.1 object is created and parsed for the inherent RC5 parameter values.

Overrides:

engineInit in class IvParameters

Parameters:

params - the DER encoded byte array

Throws:

IOException - if an error occurs when decoding the given byte array or the derived parameter values are invalid

engineInit

protected void engineInit(byte[] params,
                          String format)
                   throws IOException

Inits the parameters from an DER encoded byte array. Format is ignored. Only calls {engineInit(params) for initializing this RC5Paramters object from the given DER encoded byte array, regardless of what is specified in the format string.

Overrides:

engineInit in class IvParameters

Parameters:

params - the DER encoded byte array

format - the encoding format; ignored

Throws:

IOException - if an error occurs when decoding the given byte array

engineToString

protected String engineToString()

Returns a String representation of the parameters.

Overrides:

engineToString in class IvParameters

Returns:

a String representation of this RC5Parameters object