com.nimbusds.jose.crypto.impl

Class ConcatKDF

java.lang.Object

com.nimbusds.jose.crypto.impl.ConcatKDF

All Implemented Interfaces:

JCAAware<JCAContext>

@ThreadSafe
public class ConcatKDF
extends Object
implements JCAAware<JCAContext>

Concatenation Key Derivation Function (KDF). This class is thread-safe.

See NIST.800-56A.

Version:

2017-06-01

Author:

Vladimir Dzhuvinov

Constructor Summary

Constructors

Constructor and Description
ConcatKDF(String jcaHashAlg) Creates a new concatenation Key Derivation Function (KDF) with the specified hash algorithm.

Method Summary

Modifier and Type	Method and Description
static byte[]	composeOtherInfo(byte[] algID, byte[] partyUInfo, byte[] partyVInfo, byte[] suppPubInfo, byte[] suppPrivInfo) Composes the other info as algID || partyUInfo || partyVInfo || suppPubInfo || suppPrivInfo.
static int	computeDigestCycles(int digestLengthBits, int keyLengthBits) Computes the required digest (hashing) cycles for the specified message digest length and derived key length.
SecretKey	deriveKey(SecretKey sharedSecret, int keyLengthBits, byte[] otherInfo) Derives a key from the specified inputs.
SecretKey	deriveKey(SecretKey sharedSecret, int keyLength, byte[] algID, byte[] partyUInfo, byte[] partyVInfo, byte[] suppPubInfo, byte[] suppPrivInfo) Derives a key from the specified inputs.
static byte[]	encodeDataWithLength(Base64URL data) Encodes the specified BASE64URL encoded data data.length || data.
static byte[]	encodeDataWithLength(byte[] data) Encodes the specified data as data.length || data.
static byte[]	encodeIntData(int data) Encodes the specified integer data as a four byte array.
static byte[]	encodeNoData() Encodes no / empty data as an empty byte array.
static byte[]	encodeStringData(String data) Encodes the specified string data as data.length || data.
String	getHashAlgorithm() Returns the JCA name of the hash algorithm.
JCAContext	getJCAContext() Returns the Java Cryptography Architecture (JCA) context.

Methods inherited from class java.lang.Object

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

Constructor Detail

ConcatKDF

public ConcatKDF(String jcaHashAlg)

Creates a new concatenation Key Derivation Function (KDF) with the specified hash algorithm.

Parameters:

jcaHashAlg - The JCA name of the hash algorithm. Must be supported and not null.

Method Detail

getHashAlgorithm

public String getHashAlgorithm()

Returns the JCA name of the hash algorithm.

Returns:

The JCA name of the hash algorithm.

getJCAContext

public JCAContext getJCAContext()

Description copied from interface: JCAAware

Returns the Java Cryptography Architecture (JCA) context. May be used to set a specific JCA security provider or secure random generator.

Specified by:

getJCAContext in interface JCAAware<JCAContext>

Returns:

The JCA context. Not null.

deriveKey

public SecretKey deriveKey(SecretKey sharedSecret,
                           int keyLengthBits,
                           byte[] otherInfo)
                    throws JOSEException

Derives a key from the specified inputs.

Parameters:

sharedSecret - The shared secret. Must not be null.

keyLengthBits - The length of the key to derive, in bits.

otherInfo - Other info, null if not specified.

Returns:

The derived key, with algorithm set to "AES".

Throws:

JOSEException - If the key derivation failed.

deriveKey

public SecretKey deriveKey(SecretKey sharedSecret,
                           int keyLength,
                           byte[] algID,
                           byte[] partyUInfo,
                           byte[] partyVInfo,
                           byte[] suppPubInfo,
                           byte[] suppPrivInfo)
                    throws JOSEException

Derives a key from the specified inputs.

Parameters:

sharedSecret - The shared secret. Must not be null.

keyLength - The length of the key to derive, in bits.

algID - The algorithm identifier, null if not specified.

partyUInfo - The partyUInfo, null if not specified.

partyVInfo - The partyVInfo null if not specified.

suppPubInfo - The suppPubInfo, null if not specified.

suppPrivInfo - The suppPrivInfo, null if not specified.

Returns:

The derived key, with algorithm set to "AES".

Throws:

JOSEException - If the key derivation failed.

composeOtherInfo

public static byte[] composeOtherInfo(byte[] algID,
                                      byte[] partyUInfo,
                                      byte[] partyVInfo,
                                      byte[] suppPubInfo,
                                      byte[] suppPrivInfo)

Composes the other info as algID || partyUInfo || partyVInfo || suppPubInfo || suppPrivInfo.

Parameters:

algID - The algorithm identifier, null if not specified.

partyUInfo - The partyUInfo, null if not specified.

partyVInfo - The partyVInfo null if not specified.

suppPubInfo - The suppPubInfo, null if not specified.

suppPrivInfo - The suppPrivInfo, null if not specified.

Returns:

The resulting other info.

computeDigestCycles

public static int computeDigestCycles(int digestLengthBits,
                                      int keyLengthBits)

Computes the required digest (hashing) cycles for the specified message digest length and derived key length.

Parameters:

digestLengthBits - The length of the message digest, in bits.

keyLengthBits - The length of the derived key, in bits.

Returns:

The digest cycles.

encodeNoData

public static byte[] encodeNoData()

Encodes no / empty data as an empty byte array.

Returns:

The encoded data.

encodeIntData

public static byte[] encodeIntData(int data)

Encodes the specified integer data as a four byte array.

Parameters:

data - The integer data to encode.

Returns:

The encoded data.

encodeStringData

public static byte[] encodeStringData(String data)

Encodes the specified string data as data.length || data.

Parameters:

data - The string data, UTF-8 encoded. May be null.

Returns:

The encoded data.

encodeDataWithLength

public static byte[] encodeDataWithLength(byte[] data)

Encodes the specified data as data.length || data.

Parameters:

data - The data to encode, may be null.

Returns:

The encoded data.

encodeDataWithLength

public static byte[] encodeDataWithLength(Base64URL data)

Encodes the specified BASE64URL encoded data data.length || data.

Parameters:

data - The data to encode, may be null.

Returns:

The encoded data.