diff --git a/core/java/src/net/i2p/crypto/DHSessionKeyBuilder.java b/core/java/src/net/i2p/crypto/DHSessionKeyBuilder.java
index 804aff1af7c8d6a6bbd99b824f4e09df037dba2d..b3c5813f13bf05746f0092b65365166dd5d1b69f 100644
--- a/core/java/src/net/i2p/crypto/DHSessionKeyBuilder.java
+++ b/core/java/src/net/i2p/crypto/DHSessionKeyBuilder.java
@@ -48,6 +48,7 @@ import net.i2p.util.RandomSource;
* @author jrandom
*/
public class DHSessionKeyBuilder {
+ private static I2PAppContext _context = I2PAppContext.getGlobalContext();
private final static Log _log = new Log(DHSessionKeyBuilder.class);
private static int MIN_NUM_BUILDERS = -1;
private static int MAX_NUM_BUILDERS = -1;
@@ -68,7 +69,7 @@ public class DHSessionKeyBuilder {
public final static String DEFAULT_DH_PRECALC_DELAY = "1000";
static {
- I2PAppContext ctx = I2PAppContext.getGlobalContext();
+ I2PAppContext ctx = _context;
try {
int val = Integer.parseInt(ctx.getProperty(PROP_DH_PRECALC_MIN, DEFAULT_DH_PRECALC_MIN));
MIN_NUM_BUILDERS = val;
@@ -305,6 +306,8 @@ public class DHSessionKeyBuilder {
_log.debug("Storing " + remaining.length + " bytes from the DH exchange by SHA256 the session key");
} else { // (buf.length >= val.length)
System.arraycopy(buf, 0, val, 0, val.length);
+ // feed the extra bytes into the PRNG
+ _context.random().harvester().feedEntropy("DH", buf, val.length, buf.length-val.length);
byte remaining[] = new byte[buf.length - val.length];
System.arraycopy(buf, val.length, remaining, 0, remaining.length);
_extraExchangedBytes.setData(remaining);
diff --git a/core/java/src/net/i2p/crypto/ElGamalAESEngine.java b/core/java/src/net/i2p/crypto/ElGamalAESEngine.java
index 085b917989565faaebf523f31767c50b23daf2e4..5cf8e9ef05b319c08a755bf6c25c5ca6547cedee 100644
--- a/core/java/src/net/i2p/crypto/ElGamalAESEngine.java
+++ b/core/java/src/net/i2p/crypto/ElGamalAESEngine.java
@@ -154,11 +154,14 @@ public class ElGamalAESEngine {
byte preIV[] = null;
+ int offset = 0;
byte key[] = new byte[SessionKey.KEYSIZE_BYTES];
- System.arraycopy(elgDecr, 0, key, 0, SessionKey.KEYSIZE_BYTES);
+ System.arraycopy(elgDecr, offset, key, 0, SessionKey.KEYSIZE_BYTES);
+ offset += SessionKey.KEYSIZE_BYTES;
usedKey.setData(key);
preIV = new byte[32];
- System.arraycopy(elgDecr, SessionKey.KEYSIZE_BYTES, preIV, 0, 32);
+ System.arraycopy(elgDecr, offset, preIV, 0, 32);
+ offset += 32;
//_log.debug("Pre IV for decryptNewSession: " + DataHelper.toString(preIV, 32));
//_log.debug("SessionKey for decryptNewSession: " + DataHelper.toString(key.getData(), 32));
@@ -168,6 +171,9 @@ public class ElGamalAESEngine {
System.arraycopy(ivHash.getData(), 0, iv, 0, 16);
_context.sha().cache().release(cache);
+ // feed the extra bytes into the PRNG
+ _context.random().harvester().feedEntropy("ElG/AES", elgDecr, offset, elgDecr.length - offset);
+
byte aesDecr[] = decryptAESBlock(data, 514, data.length-514, usedKey, iv, null, foundTags, foundKey);
if (_log.shouldLog(Log.DEBUG))
@@ -403,6 +409,8 @@ public class ElGamalAESEngine {
elgEncr = elg;
}
//_log.debug("ElGamal encrypted length: " + elgEncr.length + " elGamal source length: " + elgSrc.toByteArray().length);
+
+ // should we also feed the encrypted elG block into the harvester?
SHA256EntryCache.CacheEntry cache = _context.sha().cache().acquire(preIV.length);
Hash ivHash = _context.sha().calculateHash(preIV, cache);
diff --git a/core/java/src/net/i2p/crypto/EntropyHarvester.java b/core/java/src/net/i2p/crypto/EntropyHarvester.java
new file mode 100644
index 0000000000000000000000000000000000000000..a635d6bf81e9dad13d0e95d749adece92e1077ae
--- /dev/null
+++ b/core/java/src/net/i2p/crypto/EntropyHarvester.java
@@ -0,0 +1,30 @@
+package net.i2p.crypto;
+
+/**
+ * Allow various components with some entropy to feed that entropy back
+ * into some PRNG. The quality of the entropy provided varies, so anything
+ * harvesting should discriminate based on the offered "source" of the
+ * entropy, silently discarding insufficient entropy sources.
+ *
+ */
+public interface EntropyHarvester {
+ /**
+ * Feed the entropy pools with data[offset:offset+len]
+ *
+ * @param source origin of the entropy, allowing the harvester to
+ * determine how much to value the data
+ * @param offset index into the data array to start
+ * @param len how many bytes to use
+ */
+ void feedEntropy(String source, byte data[], int offset, int len);
+ /**
+ * Feed the entropy pools with the bits in the data
+ *
+ * @param source origin of the entropy, allowing the harvester to
+ * determine how much to value the data
+ * @param bitoffset bit index into the data array to start
+ * (using java standard big-endian)
+ * @param bits how many bits to use
+ */
+ void feedEntropy(String source, long data, int bitoffset, int bits);
+}
diff --git a/core/java/src/net/i2p/util/RandomSource.java b/core/java/src/net/i2p/util/RandomSource.java
index f5508203f3c915802b910881dc787651f0a79c9f..cf320d599446bb280240c90855778775928945d2 100644
--- a/core/java/src/net/i2p/util/RandomSource.java
+++ b/core/java/src/net/i2p/util/RandomSource.java
@@ -12,6 +12,7 @@ package net.i2p.util;
import java.security.SecureRandom;
import net.i2p.I2PAppContext;
+import net.i2p.crypto.EntropyHarvester;
/**
* Singleton for whatever PRNG i2p uses.
@@ -20,10 +21,14 @@ import net.i2p.I2PAppContext;
*/
public class RandomSource extends SecureRandom {
private Log _log;
+ private EntropyHarvester _entropyHarvester;
public RandomSource(I2PAppContext context) {
super();
_log = context.logManager().getLog(RandomSource.class);
+ // when we replace to have hooks for fortuna (etc), replace with
+ // a factory (or just a factory method)
+ _entropyHarvester = new DummyEntropyHarvester();
}
public static RandomSource getInstance() {
return I2PAppContext.getGlobalContext().random();
@@ -62,4 +67,12 @@ public class RandomSource extends SecureRandom {
super.nextBytes(bytes);
}
}
+
+ public EntropyHarvester harvester() { return _entropyHarvester; }
+
+ // noop
+ private static class DummyEntropyHarvester implements EntropyHarvester {
+ public void feedEntropy(String source, long data, int bitoffset, int bits) {}
+ public void feedEntropy(String source, byte[] data, int offset, int len) {}
+ }
}
\ No newline at end of file