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performance: cache session keys per compatible S2K configuration

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This commit is contained in:
Vincent Breitmoser
2016-02-01 15:21:33 +01:00
parent cbf6f15d91
commit e3b8cea04d
5 changed files with 266 additions and 6 deletions
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27
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/CanonicalizedSecretKey.java
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@@ -19,6 +19,7 @@
package org.sufficientlysecure.keychain.pgp;
import org.spongycastle.bcpg.S2K;
import org.spongycastle.bcpg.SymmetricKeyAlgorithmTags;
import org.spongycastle.openpgp.PGPException;
import org.spongycastle.openpgp.PGPPrivateKey;
import org.spongycastle.openpgp.PGPSecretKey;
@@ -33,6 +34,7 @@ import org.spongycastle.openpgp.operator.jcajce.JcaPGPKeyConverter;
import org.spongycastle.openpgp.operator.jcajce.JcePBESecretKeyDecryptorBuilder;
import org.spongycastle.openpgp.operator.jcajce.JcePublicKeyDataDecryptorFactoryBuilder;
import org.spongycastle.openpgp.operator.jcajce.NfcSyncPGPContentSignerBuilder;
import org.spongycastle.openpgp.operator.jcajce.SessionKeySecretKeyDecryptorBuilder;
import org.sufficientlysecure.keychain.Constants;
import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralException;
import org.sufficientlysecure.keychain.pgp.exception.PgpKeyNotFoundException;
@@ -145,13 +147,12 @@ public class CanonicalizedSecretKey extends CanonicalizedPublicKey {
// Otherwise, it's just a regular ol' passphrase
return SecretKeyType.PASSPHRASE;
}
}
/**
* Returns true on right passphrase
*/
public boolean unlock(Passphrase passphrase) throws PgpGeneralException {
public boolean unlock(final Passphrase passphrase) throws PgpGeneralException {
// handle keys on OpenPGP cards like they were unlocked
S2K s2k = mSecretKey.getS2K();
if (s2k != null
@@ -163,8 +164,26 @@ public class CanonicalizedSecretKey extends CanonicalizedPublicKey {
// try to extract keys using the passphrase
try {
PBESecretKeyDecryptor keyDecryptor = new JcePBESecretKeyDecryptorBuilder().setProvider(
Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(passphrase.getCharArray());
int keyEncryptionAlgorithm = mSecretKey.getKeyEncryptionAlgorithm();
if (keyEncryptionAlgorithm == SymmetricKeyAlgorithmTags.NULL) {
mPrivateKey = mSecretKey.extractPrivateKey(null);
mPrivateKeyState = PRIVATE_KEY_STATE_UNLOCKED;
return true;
}
byte[] sessionKey;
sessionKey = passphrase.getCachedSessionKeyForAlgorithm(keyEncryptionAlgorithm, s2k);
if (sessionKey == null) {
PBESecretKeyDecryptor keyDecryptor = new JcePBESecretKeyDecryptorBuilder().setProvider(
Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(passphrase.getCharArray());
// this operation is EXPENSIVE, so we cache its result in the passed Passphrase object!
sessionKey = keyDecryptor.makeKeyFromPassPhrase(keyEncryptionAlgorithm, s2k);
passphrase.addCachedSessionKey(keyEncryptionAlgorithm, s2k, sessionKey);
}
PBESecretKeyDecryptor keyDecryptor = new SessionKeySecretKeyDecryptorBuilder()
.setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(sessionKey);
mPrivateKey = mSecretKey.extractPrivateKey(keyDecryptor);
mPrivateKeyState = PRIVATE_KEY_STATE_UNLOCKED;
} catch (PGPException e) {

91
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/ComparableS2K.java Normal file
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@@ -0,0 +1,91 @@
package org.sufficientlysecure.keychain.pgp;
import java.util.Arrays;
import android.os.Parcel;
import android.os.Parcelable;
import org.spongycastle.bcpg.S2K;
public class ComparableS2K implements Parcelable {
int encryptionAlgorithm;
int s2kType;
int s2kHashAlgo;
long s2kItCount;
byte[] s2kIV;
Integer cachedHashCode;
public ComparableS2K(int encryptionAlgorithm, S2K s2k) {
this.encryptionAlgorithm = encryptionAlgorithm;
this.s2kType = s2k.getType();
this.s2kHashAlgo = s2k.getHashAlgorithm();
this.s2kItCount = s2k.getIterationCount();
this.s2kIV = s2k.getIV();
}
protected ComparableS2K(Parcel in) {
encryptionAlgorithm = in.readInt();
s2kType = in.readInt();
s2kHashAlgo = in.readInt();
s2kItCount = in.readLong();
s2kIV = in.createByteArray();
}
@Override
public int hashCode() {
if (cachedHashCode == null) {
cachedHashCode = encryptionAlgorithm;
cachedHashCode *= 31 * s2kType;
cachedHashCode *= 31 * s2kHashAlgo;
cachedHashCode *= (int) (31 * s2kItCount);
cachedHashCode *= 31 * Arrays.hashCode(s2kIV);
}
return cachedHashCode;
}
@Override
public boolean equals(Object o) {
boolean isComparableS2K = o instanceof ComparableS2K;
if (!isComparableS2K) {
return false;
}
ComparableS2K other = (ComparableS2K) o;
return encryptionAlgorithm == other.encryptionAlgorithm
&& s2kType == other.s2kType
&& s2kHashAlgo == other.s2kHashAlgo
&& s2kItCount == other.s2kItCount
&& Arrays.equals(s2kIV, other.s2kIV);
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(encryptionAlgorithm);
dest.writeInt(s2kType);
dest.writeInt(s2kHashAlgo);
dest.writeLong(s2kItCount);
dest.writeByteArray(s2kIV);
}
public static final Creator<ComparableS2K> CREATOR = new Creator<ComparableS2K>() {
@Override
public ComparableS2K createFromParcel(Parcel in) {
return new ComparableS2K(in);
}
@Override
public ComparableS2K[] newArray(int size) {
return new ComparableS2K[size];
}
};
}

2
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpDecryptVerifyOperation.java
View File

@@ -610,6 +610,8 @@ public class PgpDecryptVerifyOperation extends BaseOperation<PgpDecryptVerifyInp
if (secretEncryptionKey.getSecretKeyType() == SecretKeyType.DIVERT_TO_CARD) {
passphrase = null;
} else if (secretKeyType == SecretKeyType.PASSPHRASE_EMPTY) {
passphrase = new Passphrase("");
} else if (cryptoInput.hasPassphrase()) {
passphrase = cryptoInput.getPassphrase();
} else {

45
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/Passphrase.java
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@@ -22,9 +22,14 @@ import android.os.Parcelable;
import android.text.Editable;
import android.widget.EditText;
import org.spongycastle.bcpg.S2K;
import org.sufficientlysecure.keychain.Constants;
import org.sufficientlysecure.keychain.pgp.ComparableS2K;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map.Entry;
/**
* Passwords should not be stored as Strings in memory.
@@ -38,6 +43,7 @@ import java.util.Arrays;
*/
public class Passphrase implements Parcelable {
private char[] mPassphrase;
HashMap<ComparableS2K, byte[]> mCachedSessionKeys;
/**
* According to http://stackoverflow.com/a/15844273 EditText is not using String internally
@@ -87,8 +93,18 @@ public class Passphrase implements Parcelable {
return mPassphrase.length;
}
public char charAt(int index) {
return mPassphrase[index];
public byte[] getCachedSessionKeyForAlgorithm(int keyEncryptionAlgorithm, S2K s2k) {
if (mCachedSessionKeys == null) {
return null;
}
return mCachedSessionKeys.get(new ComparableS2K(keyEncryptionAlgorithm, s2k));
}
public void addCachedSessionKey(int keyEncryptionAlgorithm, S2K s2k, byte[] sessionKey) {
if (mCachedSessionKeys == null) {
mCachedSessionKeys = new HashMap<>();
}
mCachedSessionKeys.put(new ComparableS2K(keyEncryptionAlgorithm, s2k), sessionKey);
}
/**
@@ -98,6 +114,12 @@ public class Passphrase implements Parcelable {
if (mPassphrase != null) {
Arrays.fill(mPassphrase, ' ');
}
if (mCachedSessionKeys == null) {
return;
}
for (byte[] cachedSessionKey : mCachedSessionKeys.values()) {
Arrays.fill(cachedSessionKey, (byte) 0);
}
}
@Override
@@ -144,10 +166,29 @@ public class Passphrase implements Parcelable {
private Passphrase(Parcel source) {
mPassphrase = source.createCharArray();
int size = source.readInt();
if (size == 0) {
return;
}
mCachedSessionKeys = new HashMap<>(size);
for (int i = 0; i < size; i++) {
ComparableS2K cachedS2K = source.readParcelable(getClass().getClassLoader());
byte[] cachedSessionKey = source.createByteArray();
mCachedSessionKeys.put(cachedS2K, cachedSessionKey);
}
}
public void writeToParcel(Parcel dest, int flags) {
dest.writeCharArray(mPassphrase);
if (mCachedSessionKeys == null || mCachedSessionKeys.isEmpty()) {
dest.writeInt(0);
return;
}
dest.writeInt(mCachedSessionKeys.size());
for (Entry<ComparableS2K,byte[]> entry : mCachedSessionKeys.entrySet()) {
dest.writeParcelable(entry.getKey(), 0);
dest.writeByteArray(entry.getValue());
}
}
public static final Creator<Passphrase> CREATOR = new Creator<Passphrase>() {