Nxt source code flaw reports - page 24.

getfun12345

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Quote from: Come-from-Beyond on January 11, 2014, 03:10:57 AM

Quote from: getfun12345 on January 11, 2014, 12:36:56 AM

The API "broadcastTransaction" doesn't check the transaction is valid.
If attacker send a transaction with large size, the transaction will be broadcasted to all peers, and the network will stuck.

It won't be broadcasted to all peers. Peers validate transactions.

But the public node who received this huge transaction, will busy to broadcasting it, can't do anything else.
The attacker can cause more damage by using less data. Depends on the peers connected to this public node.

Come-from-Beyond

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Quote from: getfun12345 on January 11, 2014, 12:36:56 AM

The API "broadcastTransaction" doesn't check the transaction is valid.
If attacker send a transaction with large size, the transaction will be broadcasted to all peers, and the network will stuck.

It won't be broadcasted to all peers. Peers validate transactions.

getfun12345

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The API "broadcastTransaction" doesn't check the transaction is valid.
If attacker send a transaction with large size, the transaction will be broadcasted to all peers, and the network will stuck.

msin

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Nice work ricot, sounds like a great option.

opticalcarrier

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Quote from: ricot on January 10, 2014, 07:22:39 PM

I just posted a proposal to fix the account number typo-problem over at the official forums:
https://forums.nxtcrypto.org/viewtopic.php?f=17&t=524 <- making NXT account numbers awesome!

What do you think about that?

thanks for posting that there. I went to the alt-client forum there and asked all the devs there who have done their own client to implement this.

lol think of the possibilities of vanity accounts with alphanumeric! actually, probably not many. the forward error correction would most likely prohibit most words from being used

ricot

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Quote from: aorith on January 10, 2014, 07:28:33 PM

Looks good, waiting to see the code!

Just updated the original post at nxtcrypto.

aorith

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Quote from: ricot on January 10, 2014, 07:22:39 PM

I just posted a proposal to fix the account number typo-problem over at the official forums:
https://forums.nxtcrypto.org/viewtopic.php?f=17&t=524 <- making NXT account numbers awesome!

What do you think about that?

Looks good, waiting to see the code!

ricot

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Activity: 56

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I just posted a proposal to fix the account number typo-problem over at the official forums:
https://forums.nxtcrypto.org/viewtopic.php?f=17&t=524 <- making NXT account numbers awesome!

What do you think about that?

gimre

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Quote from: ZeroTheGreat on January 10, 2014, 05:07:09 PM

Quote from: Come-from-Beyond on January 04, 2014, 10:06:07 AM

Quote from: ImmortAlex on January 04, 2014, 10:01:41 AM

So what's the reason? There was some deleted code?

Maybe

Stopping of generating blocks from height 20001 cos signatures'll stay unverified by condition?

Quote

1250:      boolean verifyGenerationSignature() {
1251:
1252:         try {
1253:
1254:            if (getLastBlock().height <= 20000) {

Why was answered undirect answer? It doesn't seem like a serious flaw.

there is else block below. This (split into if<=20000) was probably done when alias system was added to the code

ZeroTheGreat

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I see )

Come-from-Beyond

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Quote from: ZeroTheGreat on January 10, 2014, 05:07:09 PM

Quote from: Come-from-Beyond on January 04, 2014, 10:06:07 AM

Quote from: ImmortAlex on January 04, 2014, 10:01:41 AM

So what's the reason? There was some deleted code?

Maybe

Stopping of generating blocks from height 20001 cos signatures'll stay unverified by condition?

Quote

1250:      boolean verifyGenerationSignature() {
1251:
1252:         try {
1253:
1254:            if (getLastBlock().height <= 20000) {

Why was answered undirect answer? It doesn't seem like a serious flaw.

Well, I can't answer some questions that r close to the injected flaws. But sometimes I don't answer the other questions so u can't find a pattern. Wink

ZeroTheGreat

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Quote from: Come-from-Beyond on January 04, 2014, 10:06:07 AM

Quote from: ImmortAlex on January 04, 2014, 10:01:41 AM

So what's the reason? There was some deleted code?

Maybe

Stopping of generating blocks from height 20001 cos signatures'll stay unverified by condition?

Quote

1250:      boolean verifyGenerationSignature() {
1251:
1252:         try {
1253:
1254:            if (getLastBlock().height <= 20000) {

Why was answered undirect answer? It doesn't seem like a serious flaw.

Come-from-Beyond

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Quote from: ZeroTheGreat on January 10, 2014, 04:24:05 PM

If we look at line 4633 (I was wrong about number in previous post):

Quote

if (!futureBlocks.isEmpty() && Block.getLastBlock().height - blocks.get(commonBlockId).height < 720) {

It seems like prohibiting deep reorg condition before "synchronized".

But 4546...

The same, this limits depth to 720 blocks.

ZeroTheGreat

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Activity: 644

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If we look at line 4633 (I was wrong about number in previous post):

Quote

if (!futureBlocks.isEmpty() && Block.getLastBlock().height - blocks.get(commonBlockId).height < 720) {

It seems like prohibiting deep reorg condition before "synchronized".

But 4546...

gimre

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Quote from: ZeroTheGreat on January 10, 2014, 03:56:07 PM

Quote from: Come-from-Beyond on January 08, 2014, 01:11:47 PM

I can't answer all the questions, coz this may reveal the flaw. Sorry.

Quote

4633: if (Block.getLastBlock().height - blocks.get(commonBlockId).height < 720) {

Should be >= 720, right? Other way network'll die with peers being stucked in second half of the first day: no next blocks'es requests. As I understood.

Certainly NOT. This is there to make sure we won't change "older" blocks

ZeroTheGreat

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Quote from: Come-from-Beyond on January 08, 2014, 01:11:47 PM

I can't answer all the questions, coz this may reveal the flaw. Sorry.

Quote

4546: if (Block.getLastBlock().height - blocks.get(commonBlockId).height < 720) {

Should be >= 720, right? Other way network'll die with peers being stucked in second half of the first day: no next blocks'es requests. As I understood.

Upd: corrected line number.

ricot

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Quote from: Come-from-Beyond on January 10, 2014, 02:56:43 PM

In ~5K blocks we r switching to next phase of TF when all the accounts r equal.

That's what I wanted to hear

Come-from-Beyond

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Quote from: ricot on January 10, 2014, 02:34:28 PM

Should I do the calculations for you again that I already did?

No need. We analyze the code without TF. With TF most of these problems disappear.

Quote from: ricot on January 10, 2014, 02:34:28 PM

Why aren't all accounts equal? (Bare the genesis account, of course)

We needed special accounts coz in the beginning someone had to forge blocks. In ~5K blocks we r switching to next phase of TF when all the accounts r equal.

ricot

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Quote from: Come-from-Beyond on January 10, 2014, 05:35:38 AM

Quote from: ricot on January 10, 2014, 05:06:49 AM

So by design the founders have the ability to increase their forging chances 73-fold???
Then this currency is dead Sad

They don't have this ability. Use math and u'll see why.

I already pointed out an attack using multiple accounts to increase forging because you only had to predict one forge before the money becomes valid. If it becomes valid right away, you don't even need to predict anything.
You can see before creating your block, which of the other founder's accounts will have the best chance at forging the next, and send the money there in the block that you are forging.
Should I do the calculations for you again that I already did?

Why aren't all accounts equal? (Bare the genesis account, of course)

jl777

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http://wiki.nxtcrypto.org/wiki/Whitepaper:Nxt has the outline of the NXT Whitepaper

It has a lot of holes, especially the technical details about how exactly the NXT protocol works at the detailed low level.

I am sure that the regulars on this thread can quickly beef up the missing details and do a much better job than what is there now. Much better.

I also think there are a few missing sections.

Often when I am stumped on a deep technical problem (like finding these injected flaws), I find that switching to english and writing out how it works clarifies things in my mind. Maybe you will get a flash of insight as you describe in detail in the whitepaper wiki.

Please help. I think the wiki magically calculates everybody's contribution and there seems to be some sort of significant bounty attached to this. This way, even if you don't find injected flaw, you can at least get part of whitepaper bounty.

James

Topic: Nxt source code flaw reports - page 24. (Read 113359 times)