iaik.security.cipher

Class CCMParameters

java.lang.Object

java.security.AlgorithmParametersSpi

iaik.security.cipher.CCMParameters

public class CCMParameters
extends java.security.AlgorithmParametersSpi

This class represents CCM parameters. The parameters specified for the CCM algorithm in RFC 5084 consist of the nonce and the length of the MAC (ICVlen):

 CCMParameters ::= SEQUENCE {
         aes-nonce         OCTET STRING (SIZE(7..13)),
         aes-ICVlen        AES-CCM-ICVlen DEFAULT 12 }

 AES-CCM-ICVlen ::= INTEGER (4 | 6 | 8 | 10 | 12 | 14 | 16)
 

Additionally, this class holds the CCM parameter associated data. The inputLength can only be specified in a CCMParameterSpec object.

CCMParameters can be generated by calling one of the AlgorithmParameters.getInstance methods. Subsequently the new AlgorithmParameters object must be initialized with a proper parameter specification (class CCMParameterSpec is recommended) or a DER encoded byte array, e.g.

 CCMParameterSpec ccmParamSpec = ...;
 AlgorithmParameters params = AlgorithmParameters.getInstance("CCM", "IAIK");
 params.init(ccmParamsSpec);
 

The CCMParameters can also be initialized with an IvParameterSpec object. In this case, the specified IV will be used as nonce.

Version:

File Revision 5

Constructor Summary

Constructors

Constructor and Description
CCMParameters() The default constructor.
CCMParameters(byte[] associatedData, byte[] nonce, int macLength) Creates CCM Parameters with the given associated data, nonce and MAC length.

Method Summary

Methods

Modifier and Type	Method and Description
static void	checkKeyAndNonceReuse(boolean check) Dis/Enables check for key/nonce reuse.
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 a CCM Parameter Specification of this CCM Parameters object.
protected void	engineInit(java.security.spec.AlgorithmParameterSpec paramSpec) Initializes this parameters object using the parameters specified in paramSpec.
protected void	engineInit(byte[] params) Initializes this CCMParameters 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 formatted string describing the CCM Parameters.
static void	setIncludeDefaultMacLengthInEncding(boolean include) Decides whether the aes-ICVlen (macLength) component should be included when encoding CCM parameters if it has the default value (12).

Methods inherited from class java.lang.Object

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

Constructor Detail

CCMParameters

public CCMParameters()
              throws java.security.InvalidAlgorithmParameterException

The default constructor. No values are set for the parameters. Use AlgorithmParameters.getInstance for obtaining CCMParameters.

Throws:

java.security.InvalidAlgorithmParameterException - if the parameter values are incorrect

CCMParameters

public CCMParameters(byte[] associatedData,
             byte[] nonce,
             int macLength)
              throws java.security.InvalidAlgorithmParameterException

Creates CCM Parameters with the given associated data, nonce and MAC length.

Parameters:

nonce - the unique nonce

macLength - number of bytes used for Authentication

Throws:

java.security.InvalidAlgorithmParameterException - if the parameter values are incorrect

Method Detail

setIncludeDefaultMacLengthInEncding

public static void setIncludeDefaultMacLengthInEncding(boolean include)

Decides whether the aes-ICVlen (macLength) component should be included when encoding CCM parameters if it has the default value (12). Although default values should be not included in DER encodings it might be required to include the default value for compatibility reasons.

Parameters:

include - whether to include a default macLength value (12) when encoding CCM parameters or not (by default the default value is not included)

checkKeyAndNonceReuse

public static void checkKeyAndNonceReuse(boolean check)

Dis/Enables check for key/nonce reuse.

CCM shall not be used with same key and nonce multiple times. We cannot check any key/nonce pair that may have been used in the past, but we can check if a Cipher has been reinitialized before used for encryption a second time. This means we only check if Cipher.init() has been called before any further Cipher.update() or Cipher.doFinal() after an encryption operation has been finished; we do not check if an Cipher.init() call has actually provided a new key/nonce combination.

Parameters:

check - true to enable key/nonce reuse check (default), false to disable it

engineGetEncoded

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

Returns the parameters as DER byte array.

Specified by:

engineGetEncoded in class java.security.AlgorithmParametersSpi

Returns:

the CCM 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(), 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 CCM 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 a CCM Parameter Specification of this CCM Parameters object. paramSpec identifies the specification class in which the parameters should be returned. If paramSpec is not CCMParameterSpec than a InvalidParameterSpecException is thrown.

Specified by:

engineGetParameterSpec in class java.security.AlgorithmParametersSpi

Parameters:

paramSpec - the specification class in which the parameters should be returned - has to be the class CCMParameterSpec

Returns:

the parameter specification.

Throws:

java.security.spec.InvalidParameterSpecException - if the requested parameter specification is inappropriate for this parameter object.

engineInit

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

Initializes this parameters object using the parameters specified in paramSpec.

Specified by:

engineInit in class java.security.AlgorithmParametersSpi

Parameters:

paramSpec - the parameter specification - must be CCMParameterSpec.

Throws:

java.security.spec.InvalidParameterSpecException - if the given parameter specification is inappropriate for the initialization of this parameter object.

engineInit

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

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

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 or the derived parameter values are invalid

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

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 formatted string describing the CCM Parameters.

Specified by:

engineToString in class java.security.AlgorithmParametersSpi

Returns:

a formatted string describing the CCM Parameters.