iaik.security.cipher

Class IvParameters

java.lang.Object

java.security.AlgorithmParametersSpi

iaik.security.cipher.IvParameters

Direct Known Subclasses:

IDEAParameters, RC2Parameters

public class IvParameters
extends java.security.AlgorithmParametersSpi

This class represents an initialization vector in opaque form and may be used for generating an opaque IV and converting it between various formats.

The initialization vector (IV) represented by this class may be used by any algorithm that needs an IV, e.g. when running a DES, TripleDES, IDEA,... cipher in CBC, PCBC, CFB or OFB mode.

IvParamters can 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 IV parameter specification or a DER encoded byte array. If the first way is chosen, the IV value for initializing the new AlgorithmParameters object immediately is taken from the given IV parameter specification; if the parameters are given as DER encoded byte array, an ASN.1 OCTET_STRING is created from this byte array for subsequently parsing the IV value, e.g.:

 IvParameterSpec ivParamSpec = ...;
 AlgorithmParameters params = AlgorithmParameters.getInstance("DES", "IAIK");
 params.init(ivParamSpec);
 

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

Field Summary

Fields

Modifier and Type	Field and Description
protected byte[]	iv

Constructor Summary

Constructors

Constructor and Description
IvParameters() The default constructor.

Method Summary

Modifier and Type	Method and Description
protected byte[]	engineGetEncoded() Returns the parameters as DER byte array.
protected byte[]	engineGetEncoded(java.lang.String format) Returns the parameters as a DER byte array.
protected java.security.spec.AlgorithmParameterSpec	engineGetParameterSpec(java.lang.Class paramSpec) Returns the IV parameters as transparent IV parameter specification of the given class type.
protected void	engineInit(java.security.spec.AlgorithmParameterSpec paramSpec) Initializes this IvParameters with the IV value from a given IvParameterspec.
protected void	engineInit(byte[] params) Initializes this IvParameters object from the given DER encoded byte array.
protected void	engineInit(byte[] params, java.lang.String format) Inits the parameters from an DER encoded byte array.
protected java.lang.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

Field Detail

iv

protected byte[] iv

Constructor Detail

IvParameters

public IvParameters()

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

Method Detail

engineGetEncoded

protected byte[] engineGetEncoded()
                           throws java.io.IOException

Returns the parameters as DER byte array.

Encodes the IV value as ASN.1 OCTET STRING.

Specified by:

engineGetEncoded in class java.security.AlgorithmParametersSpi

Returns:

the IV parameters as DER byte array

Throws:

java.io.IOException - if an encoding error occurs

engineGetEncoded

protected byte[] engineGetEncoded(java.lang.String format)
                           throws java.io.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() for encoding the IV value as ASN.1 OCTET STRING, regardless of what is specified in the format string.

Specified by:

engineGetEncoded in class java.security.AlgorithmParametersSpi

Parameters:

format - the encoding format; ignored

Returns:

the IV parameters as DER byte array

Throws:

java.io.IOException - if an encoding error occurs

engineGetParameterSpec

protected java.security.spec.AlgorithmParameterSpec engineGetParameterSpec(java.lang.Class paramSpec)
                                                                    throws java.security.spec.InvalidParameterSpecException

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

Specified by:

engineGetParameterSpec in class java.security.AlgorithmParametersSpi

Parameters:

paramSpec - the desired parameter specification class (IvParameterSpec)

Returns:

the IV parameters as IvParameterSpec

Throws:

java.security.spec.InvalidParameterSpecException - if the paramters cannot be converted to the desired parameter specification

engineInit

protected void engineInit(java.security.spec.AlgorithmParameterSpec paramSpec)
                   throws java.security.spec.InvalidParameterSpecException

Initializes this IvParameters with the IV value from a given IvParameterspec.

Attention! No check is performed if the length of the IV value (derived from the IvParameterSpec) is suitable for the algorithm this IvParameters is used for.

Specified by:

engineInit in class java.security.AlgorithmParametersSpi

Parameters:

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

Throws:

java.security.spec.InvalidParameterSpecException - if the given parameter specification is not a IvParameterSpec

engineInit

protected void engineInit(byte[] params)
                   throws java.io.IOException

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

From the given byte array an ASN.1 object is created and parsed for the required IV value.

Attention! No check is performed if the length of the IV value (derived from the encoding) is suitable for the algorithm this IvParameters is used for.

Specified by:

engineInit in class java.security.AlgorithmParametersSpi

Parameters:

params - the DER encoded byte array

Throws:

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

engineInit

protected void engineInit(byte[] params,
                          java.lang.String format)
                   throws java.io.IOException

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

Attention! No check is performed if the length of the IV value (derived from the encoding) is suitable for the algorithm this IvParameters is used for.

Specified by:

engineInit in class java.security.AlgorithmParametersSpi

Parameters:

params - the DER encoded byte array

format - the encoding format; ignored

Throws:

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

engineToString

protected java.lang.String engineToString()

Returns a String representation of the parameters.

Specified by:

engineToString in class java.security.AlgorithmParametersSpi

Returns:

a String representation of this IvParameters object