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*
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* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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package com.sun.crypto.provider;
import java.util.Arrays;
import java.nio.ByteBuffer;
import javax.crypto.MacSpi;
import javax.crypto.SecretKey;
import java.security.*;
import java.security.spec.*;
/**
* This class constitutes the core of HMAC-<MD> algorithms, where
* <MD> can be SHA1 or MD5, etc.
*
* It also contains the implementation classes for the SHA-256,
* SHA-384, and SHA-512 HMACs.
*
* @author Jan Luehe
*/
final class HmacCore implements Cloneable {
private final MessageDigest md;
private final byte[] k_ipad; // inner padding - key XORd with ipad
private final byte[] k_opad; // outer padding - key XORd with opad
private boolean first; // Is this the first data to be processed?
private final int blockLen;
/**
* Standard constructor, creates a new HmacCore instance using the
* specified MessageDigest object.
*/
HmacCore(MessageDigest md, int bl) {
this.md = md;
this.blockLen = bl;
this.k_ipad = new byte[blockLen];
this.k_opad = new byte[blockLen];
first = true;
}
/**
* Standard constructor, creates a new HmacCore instance instantiating
* a MessageDigest of the specified name.
*/
HmacCore(String digestAlgorithm, int bl) throws NoSuchAlgorithmException {
this(MessageDigest.getInstance(digestAlgorithm), bl);
}
/**
* Constructor used for cloning.
*/
private HmacCore(HmacCore other) throws CloneNotSupportedException {
this.md = (MessageDigest)other.md.clone();
this.blockLen = other.blockLen;
this.k_ipad = (byte[])other.k_ipad.clone();
this.k_opad = (byte[])other.k_opad.clone();
this.first = other.first;
}
/**
* Returns the length of the HMAC in bytes.
*
* @return the HMAC length in bytes.
*/
int getDigestLength() {
return this.md.getDigestLength();
}
/**
* Initializes the HMAC with the given secret key and algorithm parameters.
*
* @param key the secret key.
* @param params the algorithm parameters.
*
* @exception InvalidKeyException if the given key is inappropriate for
* initializing this MAC.
* @exception InvalidAlgorithmParameterException if the given algorithm
* parameters are inappropriate for this MAC.
*/
void init(Key key, AlgorithmParameterSpec params)
throws InvalidKeyException, InvalidAlgorithmParameterException {
if (params != null) {
throw new InvalidAlgorithmParameterException
("HMAC does not use parameters");
}
if (!(key instanceof SecretKey)) {
throw new InvalidKeyException("Secret key expected");
}
byte[] secret = key.getEncoded();
if (secret == null || secret.length == 0) {
throw new InvalidKeyException("Missing key data");
}
// if key is longer than the block length, reset it using
// the message digest object.
if (secret.length > blockLen) {
byte[] tmp = md.digest(secret);
// now erase the secret
Arrays.fill(secret, (byte)0);
secret = tmp;
}
// XOR k with ipad and opad, respectively
for (int i = 0; i < blockLen; i++) {
int si = (i < secret.length) ? secret[i] : 0;
k_ipad[i] = (byte)(si ^ 0x36);
k_opad[i] = (byte)(si ^ 0x5c);
}
// now erase the secret
Arrays.fill(secret, (byte)0);
secret = null;
reset();
}
/**
* Processes the given byte.
*
* @param input the input byte to be processed.
*/
void update(byte input) {
if (first == true) {
// compute digest for 1st pass; start with inner pad
md.update(k_ipad);
first = false;
}
// add the passed byte to the inner digest
md.update(input);
}
/**
* Processes the first <code>len</code> bytes in <code>input</code>,
* starting at <code>offset</code>.
*
* @param input the input buffer.
* @param offset the offset in <code>input</code> where the input starts.
* @param len the number of bytes to process.
*/
void update(byte input[], int offset, int len) {
if (first == true) {
// compute digest for 1st pass; start with inner pad
md.update(k_ipad);
first = false;
}
// add the selected part of an array of bytes to the inner digest
md.update(input, offset, len);
}
void update(ByteBuffer input) {
if (first == true) {
// compute digest for 1st pass; start with inner pad
md.update(k_ipad);
first = false;
}
md.update(input);
}
/**
* Completes the HMAC computation and resets the HMAC for further use,
* maintaining the secret key that the HMAC was initialized with.
*
* @return the HMAC result.
*/
byte[] doFinal() {
if (first == true) {
// compute digest for 1st pass; start with inner pad
md.update(k_ipad);
} else {
first = true;
}
try {
// finish the inner digest
byte[] tmp = md.digest();
// compute digest for 2nd pass; start with outer pad
md.update(k_opad);
// add result of 1st hash
md.update(tmp);
md.digest(tmp, 0, tmp.length);
return tmp;
} catch (DigestException e) {
// should never occur
throw new ProviderException(e);
}
}
/**
* Resets the HMAC for further use, maintaining the secret key that the
* HMAC was initialized with.
*/
void reset() {
if (first == false) {
md.reset();
first = true;
}
}
/*
* Clones this object.
*/
public Object clone() throws CloneNotSupportedException {
return new HmacCore(this);
}
// nested static class for the HmacSHA256 implementation
public static final class HmacSHA256 extends MacSpi implements Cloneable {
private final HmacCore core;
public HmacSHA256() throws NoSuchAlgorithmException {
SunJCE.ensureIntegrity(getClass());
core = new HmacCore("SHA-256", 64);
}
private HmacSHA256(HmacSHA256 base) throws CloneNotSupportedException {
core = (HmacCore)base.core.clone();
}
protected int engineGetMacLength() {
return core.getDigestLength();
}
protected void engineInit(Key key, AlgorithmParameterSpec params)
throws InvalidKeyException, InvalidAlgorithmParameterException {
core.init(key, params);
}
protected void engineUpdate(byte input) {
core.update(input);
}
protected void engineUpdate(byte input[], int offset, int len) {
core.update(input, offset, len);
}
protected void engineUpdate(ByteBuffer input) {
core.update(input);
}
protected byte[] engineDoFinal() {
return core.doFinal();
}
protected void engineReset() {
core.reset();
}
public Object clone() throws CloneNotSupportedException {
return new HmacSHA256(this);
}
}
// nested static class for the HmacSHA384 implementation
public static final class HmacSHA384 extends MacSpi implements Cloneable {
private final HmacCore core;
public HmacSHA384() throws NoSuchAlgorithmException {
SunJCE.ensureIntegrity(getClass());
core = new HmacCore("SHA-384", 128);
}
private HmacSHA384(HmacSHA384 base) throws CloneNotSupportedException {
core = (HmacCore)base.core.clone();
}
protected int engineGetMacLength() {
return core.getDigestLength();
}
protected void engineInit(Key key, AlgorithmParameterSpec params)
throws InvalidKeyException, InvalidAlgorithmParameterException {
core.init(key, params);
}
protected void engineUpdate(byte input) {
core.update(input);
}
protected void engineUpdate(byte input[], int offset, int len) {
core.update(input, offset, len);
}
protected void engineUpdate(ByteBuffer input) {
core.update(input);
}
protected byte[] engineDoFinal() {
return core.doFinal();
}
protected void engineReset() {
core.reset();
}
public Object clone() throws CloneNotSupportedException {
return new HmacSHA384(this);
}
}
// nested static class for the HmacSHA512 implementation
public static final class HmacSHA512 extends MacSpi implements Cloneable {
private final HmacCore core;
public HmacSHA512() throws NoSuchAlgorithmException {
SunJCE.ensureIntegrity(getClass());
core = new HmacCore("SHA-512", 128);
}
private HmacSHA512(HmacSHA512 base) throws CloneNotSupportedException {
core = (HmacCore)base.core.clone();
}
protected int engineGetMacLength() {
return core.getDigestLength();
}
protected void engineInit(Key key, AlgorithmParameterSpec params)
throws InvalidKeyException, InvalidAlgorithmParameterException {
core.init(key, params);
}
protected void engineUpdate(byte input) {
core.update(input);
}
protected void engineUpdate(byte input[], int offset, int len) {
core.update(input, offset, len);
}
protected void engineUpdate(ByteBuffer input) {
core.update(input);
}
protected byte[] engineDoFinal() {
return core.doFinal();
}
protected void engineReset() {
core.reset();
}
public Object clone() throws CloneNotSupportedException {
return new HmacSHA512(this);
}
}
}