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- Correct errors in the specification of the BuildResponseRecord.

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The first 32 bytes are not random; they are the hash of the following 496 bytes.
- Don't waste entropy on bytes we are going to overwrite in the BRR
This commit is contained in:
zzz
2013-06-06 15:24:01 +00:00
parent b7dc8f425e
commit e1c68d22a3
1 changed files with 4 additions and 3 deletions
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7
router/java/src/net/i2p/data/i2np/BuildResponseRecord.java
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@ -10,7 +10,8 @@ import net.i2p.data.SessionKey;
* Read and write the reply to a tunnel build message record. * Read and write the reply to a tunnel build message record.
* *
* The reply record is the same size as the request record (528 bytes). * The reply record is the same size as the request record (528 bytes).
* Bytes 0-526 contain random data. * Bytes 0-31 contain the hash of bytes 32-527
* Bytes 32-526 contain random data.
* Byte 527 contains the reply. * Byte 527 contains the reply.
*/ */
public class BuildResponseRecord { public class BuildResponseRecord {
@ -18,14 +19,14 @@ public class BuildResponseRecord {
/** /**
* Create a new encrypted response * Create a new encrypted response
* *
* @param status the response * @param status the response 0-255
* @param responseMessageId unused except for debugging * @param responseMessageId unused except for debugging
* @return a 528-byte response record * @return a 528-byte response record
*/ */
public static byte[] create(I2PAppContext ctx, int status, SessionKey replyKey, byte replyIV[], long responseMessageId) { public static byte[] create(I2PAppContext ctx, int status, SessionKey replyKey, byte replyIV[], long responseMessageId) {
//Log log = ctx.logManager().getLog(BuildResponseRecord.class); //Log log = ctx.logManager().getLog(BuildResponseRecord.class);
byte rv[] = new byte[TunnelBuildReplyMessage.RECORD_SIZE]; byte rv[] = new byte[TunnelBuildReplyMessage.RECORD_SIZE];
ctx.random().nextBytes(rv); ctx.random().nextBytes(rv, Hash.HASH_LENGTH, TunnelBuildReplyMessage.RECORD_SIZE - Hash.HASH_LENGTH - 1);
DataHelper.toLong(rv, TunnelBuildMessage.RECORD_SIZE-1, 1, status); DataHelper.toLong(rv, TunnelBuildMessage.RECORD_SIZE-1, 1, status);
// rv = AES(SHA256(padding+status) + padding + status, replyKey, replyIV) // rv = AES(SHA256(padding+status) + padding + status, replyKey, replyIV)
ctx.sha().calculateHash(rv, Hash.HASH_LENGTH, rv.length - Hash.HASH_LENGTH, rv, 0); ctx.sha().calculateHash(rv, Hash.HASH_LENGTH, rv.length - Hash.HASH_LENGTH, rv, 0);