iaik.pkcs.pkcs1

Class RSAOaepParameterSpec

java.lang.Object

iaik.pkcs.pkcs1.PKCS1AlgorithmParameterSpec

iaik.pkcs.pkcs1.RSAOaepPSourceParameterSpec

iaik.pkcs.pkcs1.RSAOaepParameterSpec

All Implemented Interfaces:

java.lang.Cloneable, java.security.spec.AlgorithmParameterSpec

public class RSAOaepParameterSpec
extends RSAOaepPSourceParameterSpec
implements java.lang.Cloneable

Algorithm parameter specification for the PKCS#1 RSAES-OAEP encryption scheme.

PKCS#1v2.1 defines the following parameters for the OAEP encryption scheme:

 RSASES-OAEP-params :: = SEQUENCE {
      hashAlgorithm            [0] HashAlgorithm     DEFAULT sha1,
      maskGenerationAlgorithm  [1] MaskGenAlgorithm  DEFAULT mgf1SHA1,
      pSourceAlgorithm         [2] PSourceAlgorithm  DEFAULT pSpecifiedEmpty,
 }
 
 HashAlgorithm ::= Algorithmidentifier { {OAEP-PSSDigestAlgorithms} }
 
 MaskGenAlgorithm ::= AlgorithmIdentifier { {PKCS1MGFAlgorithms} }
 
 PSourceAlgorithm ::= AlgorithmIdentifier { {PKCS1PSourceAlgorithms} }
 

By default OAEP uses SHA-1 as hash function, MGF1 (with SHA-1 as hash function parameter) as mask generation algorithm, and id-pSpecified as PSourceAlgorithm (with an empty OCTET STRING as parameter).

Hash algorithm, mask generation function, and PSourceAlgorithm have to be supplied when creating a creating a RSAOaepParameterSpec object, e.g.:

 // hash, mgf and pSource algorithm ids
 AlgorithmID hashID = (AlgorithmID) AlgorithmID.sha1.clone();
 AlgorithmID mgfID = (AlgorithmID) AlgorithmID.mgf1.clone();
 mgfID.setParameter(hashID.toASN1Object());
 AlgorithmID pSourceID = (AlgorithmID) AlgorithmID.pSpecified.clone();
 pSourceID.setParameter(new OCTET_STRING());
 // hash and mgf engines
 MessageDigest hashEngine = hashID.getMessageDigestInstance();
 MaskGenerationAlgorithm mgfEngine = mgfID.getMaskGenerationAlgorithmInstance();
 MGF1ParameterSpec mgf1ParamSpec = new MGF1ParameterSpec(hashID);
 mgf1ParamSpec.setHashEngine(hashEngine);
 mgfEngine.setParameters(mgf1ParamSpec);
 // create the RSAOaepParameterSpec
 RSAOaepParameterSpec oaepParamSpec = new RSAOaepParameterSpec(hashID, mgfID,
     pSourceID);
 // set engines
 oaepParamSpec.setHashEngine(hashEngine);
 oaepParamSpec.setMGFEngine(mgfEngine);
 

Version:

File Revision 12

See Also:

RSAOaepParameters, MaskGenerationAlgorithm, MGF1, MGF1ParameterSpec, RSACipher, AlgorithmID, OCTET_STRING

Field Summary

Fields

Modifier and Type	Field and Description
static AlgorithmID	DEFAULT_HASH_ALGORITHM Default hash algorithm (SHA-1).
static AlgorithmID	DEFAULT_MASK_GEN_ALGORITHM Default mask generation algorithm (MGF1 with SHA1 as hash algorithm)

Fields inherited from class iaik.pkcs.pkcs1.RSAOaepPSourceParameterSpec

DEFAULT_PSOURCE_ALGORITHM, pSourceAlgorithm_

Constructor Summary

Constructors

Constructor and Description
RSAOaepParameterSpec() Creates default RSAES-OAEP parameters.
RSAOaepParameterSpec(AlgorithmID hashAlgorithm, AlgorithmID maskGenAlgorithm, AlgorithmID pSourceAlgorithm) Creates a RSAOaepParameterSpec for the given hash algorithm, mask generation function, and pSource algorithm.

Method Summary

Methods

Modifier and Type	Method and Description
java.lang.Object	clone() Returns a clone of this Object.
boolean	equals(java.lang.Object obj) Compares this RSAOaepParameterSpec object with the supplied object.
java.lang.Boolean	getEncodeDefaultValues() This method shows if parameter values should be encoded even if they have the default values; e.g.
AlgorithmID	getHashAlgorithm() Returns the hash algorithm.
java.security.MessageDigest	getHashEngine() Gets the JCA MessageDigest engine used for data hashing.
AlgorithmID	getMaskGenAlgorithm() Gets the mask generation algorithm.
MaskGenerationAlgorithm	getMGFEngine() Gets the MaskGenerationAlgorithm engine.
int	hashCode() Gets a hash code for this object.
void	setEncodeDefaultValues(java.lang.Boolean encode) With this method, the application can define that parameter values should be encoded even if they have the default values; e.g.
void	setHashEngine(java.security.MessageDigest hashEngine) Sets the JCA MessageDigest engine to be used for data hashing.
void	setMGFEngine(MaskGenerationAlgorithm mgfEngine) Sets the MaskGenerationAlgorithm engine to be used.
java.lang.String	toString() Returns a string representation of this RSAOaepParameterSpec.

Methods inherited from class iaik.pkcs.pkcs1.RSAOaepPSourceParameterSpec

getDefault, getLabel, getPSourceAlgorithm, setLabel

Methods inherited from class iaik.pkcs.pkcs1.PKCS1AlgorithmParameterSpec

getSecureRandom, setSecureRandom

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

DEFAULT_HASH_ALGORITHM

public static final AlgorithmID DEFAULT_HASH_ALGORITHM

Default hash algorithm (SHA-1).

DEFAULT_MASK_GEN_ALGORITHM

public static final AlgorithmID DEFAULT_MASK_GEN_ALGORITHM

Default mask generation algorithm (MGF1 with SHA1 as hash algorithm)

Constructor Detail

RSAOaepParameterSpec

public RSAOaepParameterSpec()

Creates default RSAES-OAEP parameters.

By default OAEP uses SHA-1 as hash function, MGF1 (with SHA-1 as hash function parameter) as mask generation algorithm, and id-pSpecified as PSourceAlgorithm (with an empty OCTET STRING as parameter), see (see PKCS#1v2.1:

 RSASES-OAEP-params :: = SEQUENCE {
      hashAlgorithm            [0] HashAlgorithm     DEFAULT sha1,
      maskGenerationAlgorithm  [1] MaskGenAlgorithm  DEFAULT mgf1SHA1,
      pSourceAlgorithm         [2] PSourceAlgorithm  DEFAULT pSpecifiedEmpty,
 }
 
 HashAlgorithm ::= Algorithmidentifier { {OAEP-PSSDigestAlgorithms} }
 
 MaskGenAlgorithm ::= AlgorithmIdentifier { {PKCS1MGFAlgorithms} }
 
 PSourceAlgorithm ::= AlgorithmIdentifier { {PKCS1PSourceAlgorithms} }
 

RSAOaepParameterSpec

public RSAOaepParameterSpec(AlgorithmID hashAlgorithm,
                    AlgorithmID maskGenAlgorithm,
                    AlgorithmID pSourceAlgorithm)

Creates a RSAOaepParameterSpec for the given hash algorithm, mask generation function, and pSource algorithm.

Parameters:

hashAlgorithm - the hash algorithm to be used

Throws:

java.lang.IllegalArgumentException - if hashAlgorithm or maskGenAlgorithm or pSourceAlgorithm are null

Method Detail

getHashAlgorithm

public AlgorithmID getHashAlgorithm()

Returns the hash algorithm.

Returns:

the hash algorithm

getMaskGenAlgorithm

public AlgorithmID getMaskGenAlgorithm()

Gets the mask generation algorithm.

Returns:

the mask generation algorithm

setHashEngine

public void setHashEngine(java.security.MessageDigest hashEngine)

Sets the JCA MessageDigest engine to be used for data hashing.

This method may be used to set a JCA MessageDigest engine to be used for doing the any required hashing operations. If not set by this method, getHashEngine will try to create a MessageDigest engine from the hash algorithm id.

Parameters:

hashEngine - the JCA MessageDigest engine to be used

getHashEngine

public java.security.MessageDigest getHashEngine()
                                          throws java.security.NoSuchAlgorithmException

Gets the JCA MessageDigest engine used for data hashing.

If method setHashEngine has been used to set a MessageDigest engine, this engine is returned; otherwise it is tried to create a MessageDigest engine from the hash algorithm id.

Returns:

the MessageDigest engine to be used

Throws:

java.security.NoSuchAlgorithmException

setMGFEngine

public void setMGFEngine(MaskGenerationAlgorithm mgfEngine)

Sets the MaskGenerationAlgorithm engine to be used.

This method may be used to set a MaskGenerationAlgorithm engine. If not set by this method, getMGFEngine will try to create a MaskGenerationAlgorithm engine from the mask generation algorithm id.

Parameters:

mgfEngine - the MaskGenerationAlgorithm engine to be used

getMGFEngine

public MaskGenerationAlgorithm getMGFEngine()
                                     throws java.security.NoSuchAlgorithmException

Gets the MaskGenerationAlgorithm engine.

If method setMGFEngine has been used to set a MGF engine, this engine is returned; otherwise it is tried to create a MGF engine from the Mask generation algorithm id.

Returns:

the MGF engine to be used

Throws:

java.security.NoSuchAlgorithmException

setEncodeDefaultValues

public void setEncodeDefaultValues(java.lang.Boolean encode)

With this method, the application can define that parameter values should be encoded even if they have the default values; e.g. if the hashAlgorithm is sha1.

Note that these settings have higher priority than those given by the RSAOaepParameters.getEncodeDefaultValues().

Note that only a value of false results in a fully correct DER encoding, because DER encoding required default values to be omitted.

Parameters:

encode - Boolean.TRUE to encode default values, Boolean.False to omit default values in the encoding. Set to null to use the current setting of RSAOaepParameters.getEncodeDefaultValues()

See Also:

RSAOaepParameters.setEncodeDefaultValues(boolean), RSAOaepParameters.getEncodeDefaultValues()

getEncodeDefaultValues

public java.lang.Boolean getEncodeDefaultValues()

This method shows if parameter values should be encoded even if they have the default values; e.g. if the hashAlgorithm is sha1.

Note that these settings have higher priority than those given by the RSAOaepParameters.getEncodeDefaultValues().

Note that only a value of false results in a fully correct DER encoding, because DER encoding required default values to be omitted.

Returns:

true if default values are encoded, false if they are omitted in the encoding.

See Also:

setEncodeDefaultValues(Boolean), RSAOaepParameters.setEncodeDefaultValues(boolean), RSAOaepParameters.getEncodeDefaultValues()

clone

public java.lang.Object clone()

Returns a clone of this Object.

Overrides:

clone in class java.lang.Object

Returns:

a clone of this Object

hashCode

public int hashCode()

Gets a hash code for this object.

Overrides:

hashCode in class RSAOaepPSourceParameterSpec

Returns:

the hash code

equals

public boolean equals(java.lang.Object obj)

Compares this RSAOaepParameterSpec object with the supplied object.

Overrides:

equals in class RSAOaepPSourceParameterSpec

Parameters:

obj - the object to be compared

Returns:

true if the two objects are RSAOaepParameterSpec objects with same hash, mgf and pSource id; false otherwise

toString

public java.lang.String toString()

Returns a string representation of this RSAOaepParameterSpec.

Overrides:

toString in class RSAOaepPSourceParameterSpec

Returns:

a string representation