iaik.security.pbe
Class PBEParameters

java.lang.Object
  |
  +--java.security.AlgorithmParametersSpi
        |
        +--iaik.security.pbe.PBEParameters

public class PBEParameters

extends AlgorithmParametersSpi

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

RSA-PKCS#5 describes a method for encrypting messages (octet strings) with secret keys derived from a password. For generating the key from the password, paramters (salt a random octet string and iteration count an integer) are required.

PBEParamters can be generated provider independently by calling one of the AlgorithmParameters.getInstance methods. Subsequently the new AlgorithmParamters object must be initialized with a proper PBE parameter specification or a DER encoded byte array. If the first way is chosen, the parameter values (salt and iteration count) for initializing the new AlgorithmParameters object are immediately taken from the given PBE parameter specification; if the parameters are given as DER encoded byte array, an ASN.1 object is created from this byte array for subsequently parsing it to get salt and iteration count.

Alternatively PBEParamerters may be created by using a proper AlgorithmParamterGenerator. The PBEParameterGenerator itself calls

 AlgorithmParameters.getInstance("PBE", "IAIK")
 

for actually generating PBEParameters in opaque representation.

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

Version:

File Revision 16

See Also:

PBEParameterGenerator, PBEGenParameterSpec, AlgorithmParameters

Constructor Summary

PBEParameters()
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 PBE parameters as transparent PBE parameter specification of the given class type.
protected void	engineInit(AlgorithmParameterSpec paramSpec) Initializes this PBEParameters with salt and iteration count from a given PBEParameterSpec or PBEKeyAndParameterSpec.
protected void	engineInit(byte[] params) Initializes this PBEParameters 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

PBEParameters

public PBEParameters()

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

Method Detail

engineGetEncoded

protected byte[] engineGetEncoded()
                           throws IOException

Returns the parameters as DER byte array.

A SEQUENCE ASN.1 object is created for holding salt and iteration count; subsequently this SEQUENCE object is DER-encoded to get the required byte array.

Overrides:

engineGetEncoded in class AlgorithmParametersSpi

Returns:

the PBE 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() for returning the PBE paramters as DER encoded byte array, regardless of what is specified in the format string.

Overrides:

engineGetEncoded in class AlgorithmParametersSpi

Parameters:

format - the encoding format; ignored

Returns:

the PBE parameters as DER byte array

Throws:

IOException - if an encoding error occurs

engineGetParameterSpec

protected AlgorithmParameterSpec engineGetParameterSpec(Class paramSpec)
                                                 throws InvalidParameterSpecException

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

Overrides:

engineGetParameterSpec in class AlgorithmParametersSpi

Parameters:

paramSpec - the desired parameter specification class

Returns:

the PBE parameters as AlgorithmParaneterSpec

Throws:

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

engineInit

protected void engineInit(AlgorithmParameterSpec paramSpec)
                   throws InvalidParameterSpecException

Initializes this PBEParameters with salt and iteration count from a given PBEParameterSpec or PBEKeyAndParameterSpec.

Overrides:

engineInit in class AlgorithmParametersSpi

Parameters:

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

Throws:

InvalidParameterSpecException - if the given parameter specification is not a PBEParameterSpec

engineInit

protected void engineInit(byte[] params)
                   throws IOException

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

From the given byte array a ASN.1 object is created to be parsed for the required salt and iteration count.

Overrides:

engineInit in class AlgorithmParametersSpi

Parameters:

params - the DER encoded byte array

Throws:

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

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 PBEParamters object from the given DER encoded byte array, regardless of what is specified in the format string.

Overrides:

engineInit in class AlgorithmParametersSpi

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 AlgorithmParametersSpi

Returns:

a String representation of this PBEParameters object