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package com.sun.crypto.provider;
import java.io.IOException;
import java.io.Serializable;
import java.security.Security;
import java.security.Key;
import java.security.PrivateKey;
import java.security.Provider;
import java.security.KeyFactory;
import java.security.MessageDigest;
import java.security.GeneralSecurityException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.UnrecoverableKeyException;
import java.security.AlgorithmParameters;
import java.security.spec.PKCS8EncodedKeySpec;
import javax.crypto.Cipher;
import javax.crypto.CipherSpi;
import javax.crypto.SecretKey;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.SealedObject;
import javax.crypto.spec.*;
import sun.security.x509.AlgorithmId;
import sun.security.util.ObjectIdentifier;
/**
* This class implements a protection mechanism for private keys. In JCE, we
* use a stronger protection mechanism than in the JDK, because we can use
* the <code>Cipher</code> class.
* Private keys are protected using the JCE mechanism, and are recovered using
* either the JDK or JCE mechanism, depending on how the key has been
* protected. This allows us to parse Sun's keystore implementation that ships
* with JDK 1.2.
*
* @author Jan Luehe
*
*
* @see JceKeyStore
*/
final class KeyProtector {
// defined by SunSoft (SKI project)
private static final String PBE_WITH_MD5_AND_DES3_CBC_OID
= "1.3.6.1.4.1.42.2.19.1";
// JavaSoft proprietary key-protection algorithm (used to protect private
// keys in the keystore implementation that comes with JDK 1.2)
private static final String KEY_PROTECTOR_OID = "1.3.6.1.4.1.42.2.17.1.1";
private static final int SALT_LEN = 20; // the salt length
private static final int DIGEST_LEN = 20;
// the password used for protecting/recovering keys passed through this
// key protector
private char[] password;
KeyProtector(char[] password) {
if (password == null) {
throw new IllegalArgumentException("password can't be null");
}
this.password = password;
}
/**
* Protects the given cleartext private key, using the password provided at
* construction time.
*/
byte[] protect(PrivateKey key)
throws Exception
{
// create a random salt (8 bytes)
byte[] salt = new byte[8];
SunJCE.getRandom().nextBytes(salt);
// create PBE parameters from salt and iteration count
PBEParameterSpec pbeSpec = new PBEParameterSpec(salt, 20);
// create PBE key from password
PBEKeySpec pbeKeySpec = new PBEKeySpec(this.password);
SecretKey sKey = new PBEKey(pbeKeySpec, "PBEWithMD5AndTripleDES");
pbeKeySpec.clearPassword();
// encrypt private key
PBEWithMD5AndTripleDESCipher cipher;
cipher = new PBEWithMD5AndTripleDESCipher();
cipher.engineInit(Cipher.ENCRYPT_MODE, sKey, pbeSpec, null);
byte[] plain = key.getEncoded();
byte[] encrKey = cipher.engineDoFinal(plain, 0, plain.length);
// wrap encrypted private key in EncryptedPrivateKeyInfo
// (as defined in PKCS#8)
AlgorithmParameters pbeParams =
AlgorithmParameters.getInstance("PBE", SunJCE.getInstance());
pbeParams.init(pbeSpec);
AlgorithmId encrAlg = new AlgorithmId
(new ObjectIdentifier(PBE_WITH_MD5_AND_DES3_CBC_OID), pbeParams);
return new EncryptedPrivateKeyInfo(encrAlg,encrKey).getEncoded();
}
/*
* Recovers the cleartext version of the given key (in protected format),
* using the password provided at construction time.
*/
Key recover(EncryptedPrivateKeyInfo encrInfo)
throws UnrecoverableKeyException, NoSuchAlgorithmException
{
byte[] plain;
try {
String encrAlg = encrInfo.getAlgorithm().getOID().toString();
if (!encrAlg.equals(PBE_WITH_MD5_AND_DES3_CBC_OID)
&& !encrAlg.equals(KEY_PROTECTOR_OID)) {
throw new UnrecoverableKeyException("Unsupported encryption "
+ "algorithm");
}
if (encrAlg.equals(KEY_PROTECTOR_OID)) {
// JDK 1.2 style recovery
plain = recover(encrInfo.getEncryptedData());
} else {
byte[] encodedParams =
encrInfo.getAlgorithm().getEncodedParams();
// parse the PBE parameters into the corresponding spec
AlgorithmParameters pbeParams =
AlgorithmParameters.getInstance("PBE");
pbeParams.init(encodedParams);
PBEParameterSpec pbeSpec =
pbeParams.getParameterSpec(PBEParameterSpec.class);
// create PBE key from password
PBEKeySpec pbeKeySpec = new PBEKeySpec(this.password);
SecretKey sKey =
new PBEKey(pbeKeySpec, "PBEWithMD5AndTripleDES");
pbeKeySpec.clearPassword();
// decrypt private key
PBEWithMD5AndTripleDESCipher cipher;
cipher = new PBEWithMD5AndTripleDESCipher();
cipher.engineInit(Cipher.DECRYPT_MODE, sKey, pbeSpec, null);
plain=cipher.engineDoFinal(encrInfo.getEncryptedData(), 0,
encrInfo.getEncryptedData().length);
}
// determine the private-key algorithm, and parse private key
// using the appropriate key factory
String oidName = new AlgorithmId
(new PrivateKeyInfo(plain).getAlgorithm().getOID()).getName();
KeyFactory kFac = KeyFactory.getInstance(oidName);
return kFac.generatePrivate(new PKCS8EncodedKeySpec(plain));
} catch (NoSuchAlgorithmException ex) {
// Note: this catch needed to be here because of the
// later catch of GeneralSecurityException
throw ex;
} catch (IOException ioe) {
throw new UnrecoverableKeyException(ioe.getMessage());
} catch (GeneralSecurityException gse) {
throw new UnrecoverableKeyException(gse.getMessage());
}
}
/*
* Recovers the cleartext version of the given key (in protected format),
* using the password provided at construction time. This method implements
* the recovery algorithm used by Sun's keystore implementation in
* JDK 1.2.
*/
private byte[] recover(byte[] protectedKey)
throws UnrecoverableKeyException, NoSuchAlgorithmException
{
int i, j;
byte[] digest;
int numRounds;
int xorOffset; // offset in xorKey where next digest will be stored
int encrKeyLen; // the length of the encrpyted key
MessageDigest md = MessageDigest.getInstance("SHA");
// Get the salt associated with this key (the first SALT_LEN bytes of
// <code>protectedKey</code>)
byte[] salt = new byte[SALT_LEN];
System.arraycopy(protectedKey, 0, salt, 0, SALT_LEN);
// Determine the number of digest rounds
encrKeyLen = protectedKey.length - SALT_LEN - DIGEST_LEN;
numRounds = encrKeyLen / DIGEST_LEN;
if ((encrKeyLen % DIGEST_LEN) != 0)
numRounds++;
// Get the encrypted key portion and store it in "encrKey"
byte[] encrKey = new byte[encrKeyLen];
System.arraycopy(protectedKey, SALT_LEN, encrKey, 0, encrKeyLen);
// Set up the byte array which will be XORed with "encrKey"
byte[] xorKey = new byte[encrKey.length];
// Convert password to byte array, so that it can be digested
byte[] passwdBytes = new byte[password.length * 2];
for (i=0, j=0; i<password.length; i++) {
passwdBytes[j++] = (byte)(password[i] >> 8);
passwdBytes[j++] = (byte)password[i];
}
// Compute the digests, and store them in "xorKey"
for (i = 0, xorOffset = 0, digest = salt;
i < numRounds;
i++, xorOffset += DIGEST_LEN) {
md.update(passwdBytes);
md.update(digest);
digest = md.digest();
md.reset();
// Copy the digest into "xorKey"
if (i < numRounds - 1) {
System.arraycopy(digest, 0, xorKey, xorOffset,
digest.length);
} else {
System.arraycopy(digest, 0, xorKey, xorOffset,
xorKey.length - xorOffset);
}
}
// XOR "encrKey" with "xorKey", and store the result in "plainKey"
byte[] plainKey = new byte[encrKey.length];
for (i = 0; i < plainKey.length; i++) {
plainKey[i] = (byte)(encrKey[i] ^ xorKey[i]);
}
// Check the integrity of the recovered key by concatenating it with
// the password, digesting the concatenation, and comparing the
// result of the digest operation with the digest provided at the end
// of <code>protectedKey</code>. If the two digest values are
// different, throw an exception.
md.update(passwdBytes);
java.util.Arrays.fill(passwdBytes, (byte)0x00);
passwdBytes = null;
md.update(plainKey);
digest = md.digest();
md.reset();
for (i = 0; i < digest.length; i++) {
if (digest[i] != protectedKey[SALT_LEN + encrKeyLen + i]) {
throw new UnrecoverableKeyException("Cannot recover key");
}
}
return plainKey;
}
/**
* Seals the given cleartext key, using the password provided at
* construction time
*/
SealedObject seal(Key key)
throws Exception
{
// create a random salt (8 bytes)
byte[] salt = new byte[8];
SunJCE.getRandom().nextBytes(salt);
// create PBE parameters from salt and iteration count
PBEParameterSpec pbeSpec = new PBEParameterSpec(salt, 20);
// create PBE key from password
PBEKeySpec pbeKeySpec = new PBEKeySpec(this.password);
SecretKey sKey = new PBEKey(pbeKeySpec, "PBEWithMD5AndTripleDES");
pbeKeySpec.clearPassword();
// seal key
Cipher cipher;
PBEWithMD5AndTripleDESCipher cipherSpi;
cipherSpi = new PBEWithMD5AndTripleDESCipher();
cipher = new CipherForKeyProtector(cipherSpi, SunJCE.getInstance(),
"PBEWithMD5AndTripleDES");
cipher.init(Cipher.ENCRYPT_MODE, sKey, pbeSpec);
return new SealedObjectForKeyProtector(key, cipher);
}
/**
* Unseals the sealed key.
*/
Key unseal(SealedObject so)
throws NoSuchAlgorithmException, UnrecoverableKeyException
{
try {
// create PBE key from password
PBEKeySpec pbeKeySpec = new PBEKeySpec(this.password);
SecretKey skey = new PBEKey(pbeKeySpec, "PBEWithMD5AndTripleDES");
pbeKeySpec.clearPassword();
SealedObjectForKeyProtector soForKeyProtector = null;
if (!(so instanceof SealedObjectForKeyProtector)) {
soForKeyProtector = new SealedObjectForKeyProtector(so);
} else {
soForKeyProtector = (SealedObjectForKeyProtector)so;
}
AlgorithmParameters params = soForKeyProtector.getParameters();
if (params == null) {
throw new UnrecoverableKeyException("Cannot get " +
"algorithm parameters");
}
PBEWithMD5AndTripleDESCipher cipherSpi;
cipherSpi = new PBEWithMD5AndTripleDESCipher();
Cipher cipher = new CipherForKeyProtector(cipherSpi,
SunJCE.getInstance(),
"PBEWithMD5AndTripleDES");
cipher.init(Cipher.DECRYPT_MODE, skey, params);
return (Key)soForKeyProtector.getObject(cipher);
} catch (NoSuchAlgorithmException ex) {
// Note: this catch needed to be here because of the
// later catch of GeneralSecurityException
throw ex;
} catch (IOException ioe) {
throw new UnrecoverableKeyException(ioe.getMessage());
} catch (ClassNotFoundException cnfe) {
throw new UnrecoverableKeyException(cnfe.getMessage());
} catch (GeneralSecurityException gse) {
throw new UnrecoverableKeyException(gse.getMessage());
}
}
}
final class CipherForKeyProtector extends javax.crypto.Cipher {
/**
* Creates a Cipher object.
*
* @param cipherSpi the delegate
* @param provider the provider
* @param transformation the transformation
*/
protected CipherForKeyProtector(CipherSpi cipherSpi,
Provider provider,
String transformation) {
super(cipherSpi, provider, transformation);
}
}