Decrypting a password-protected 7z file with Delta filter fails

I have made a 7z archive using Delta filter containing a wav file and I have protected it with a password. I am running a terminal in Kali Linux. My problem is that I cannot get the password cracked using 7z2john.pl and john the ripper. If I omit the Delta compression, using only the default compression of 7z, then the cracking succeeds. My question: is it possible to use 7z2john.pl and john the ripper to crack a password-protected 7z file with Delta compression? If it is possible, how can it be done?

Here are the steps to reproduce the problem:

  1. I use the following command to create the archive:

7z a test.7z *.wav -mf=Delta:4 -peasy

I get this output:

7-Zip [64] 16.02 : Copyright (c) 1999-2016 Igor Pavlov : 2016-05-21 p7zip Version 16.02 (locale=fi_FI.utf8,Utf16=on,HugeFiles=on,64 bits,4 CPUs Intel(R) Core(TM) i5-4460  CPU @ 3.20GHz (306C3),ASM,AES-NI)  Open archive: test.7z -- Path = test.7z Type = 7z Physical Size = 1090 Headers Size = 162 Method = Delta LZMA2:15 7zAES Solid = - Blocks = 1  Scanning the drive: 1 file, 32080 bytes (32 KiB)  Updating archive: test.7z  Items to compress: 1       Files read from disk: 1 Archive size: 1090 bytes (2 KiB) Everything is Ok  
  1. I use 7z2john.pl to generate material for John the Ripper to crack the archive:

/usr/share/john/7z2john.pl test.7z > test.hash

  1. I create a word list file containing only the password I gave to the archive:

echo easy > wordlist.txt

Then I try to decrypt the file:

sudo john test.hash --wordlist=wordlist.txt

I get the following output:

Using default input encoding: UTF-8 Loaded 1 password hash (7z, 7-Zip [SHA256 256/256 AVX2 8x AES]) Cost 1 (iteration count) is 524288 for all loaded hashes Cost 2 (padding size) is 3 for all loaded hashes Cost 3 (compression type) is 2 for all loaded hashes Will run 4 OpenMP threads Press 'q' or Ctrl-C to abort, almost any other key for status Warning: Only 1 candidate left, minimum 32 needed for performance. 0g 0:00:00:00 DONE (2020-08-15 07:37) 0g/s 5.555p/s 5.555c/s 5.555C/s easy Session completed 
  1. I check if the password has been cracked: sudo john --show test.hash

I get the following output:

0 password hashes cracked, 1 left

So it seems that the decrypting did not succeed. However, I can extract the archive using command 7z e test.7z -peasy so the password should be correct. Also, if I create the archive without specifying the Delta filter using command 7z a test.7z *.wav -peasy. That way, by repeating the steps 1-4 I get the password cracked and am shown the result that the correct password has been found:

$   7z a test.7z *.wav -peasy  7-Zip [64] 16.02 : Copyright (c) 1999-2016 Igor Pavlov : 2016-05-21 p7zip Version 16.02 (locale=fi_FI.utf8,Utf16=on,HugeFiles=on,64 bits,4 CPUs Intel(R) Core(TM) i5-4460  CPU @ 3.20GHz (306C3),ASM,AES-NI)  Scanning the drive: 1 file, 32080 bytes (32 KiB)  Creating archive: test.7z  Items to compress: 1       Files read from disk: 1 Archive size: 1058 bytes (2 KiB) Everything is Ok  $   /usr/share/john/7z2john.pl test.7z > test.hash $   echo easy >> wordlist.txt $   sudo john test.hash --wordlist=wordlist.txt Using default input encoding: UTF-8 Loaded 1 password hash (7z, 7-Zip [SHA256 256/256 AVX2 8x AES]) Cost 1 (iteration count) is 524288 for all loaded hashes Cost 2 (padding size) is 11 for all loaded hashes Cost 3 (compression type) is 2 for all loaded hashes Will run 4 OpenMP threads Press 'q' or Ctrl-C to abort, almost any other key for status Warning: Only 1 candidate left, minimum 32 needed for performance. easy             (test.7z) 1g 0:00:00:00 DONE (2020-08-15 07:49) 5.263g/s 5.263p/s 5.263c/s 5.263C/s easy Use the "--show" option to display all of the cracked passwords reliably Session completed $   sudo john --show test.hash test.7z:easy  1 password hash cracked, 0 left  

Delta Green and handedness

I AM STARTING A POST APOCALYPSE DELTA GREEN GAME WHERE THE GROUP IS TASKED WITH TRYING TO REPAIR SOCIETY. i HADONE PERSON ASK CAN THEY USE Two weapons one in each hand. I can’t not find anything about this can someone give me some help with question. Our next session is2nd weekend in July.

Delta rule for binary step function

I have a question of understanding about the Delta Rule:

Δwᵢ = (y – ŷ)*xᵢ

Why does x have to be multiplied again after the difference? If the input is 0, the product of w and x remains 0 anyway. Then it should not matter if the weight changes with an input of 0.

let us take the following example:

  • w_i = the ith weight of the weight vector
  • Δw_i = the change in weight w_i
  • y = the desired output of the neuron for the learning example
  • ŷ = the actual, calculated output for the learning example
  • x_i = the input

Step t:

  • Input (x) = 1 0 0
  • Random weights = 0.1 0.1 0.1
  • Scalar product –> 0.1
  • Step function outputs 1 –> ŷ = 1

BUT we want as output y = 0 So the weights have to be adjusted as follows:

Step t+1:

  • Δw_0 = (0 – 1) * 1 = -1
  • Δw_1 = (0 – 1) * 0 = 0
  • Δw_2 = (0 – 1) * 0 = 0

w_i(new) = w_i(old) + Δw_i

  • New weights: -0.9 0.1 0.1
  • Scalar product = -0.9
  • Output (y = 0)

You can totally skip the multiplication by x, can’t you? Because at the latest when the scalar product is created, the weight which is multiplied by x = 0 is still not included. So why multiply by x in the delta w?

Maximizing integer sets intersection (with integer delta)

There are two sets of integers with different numbers of items in them.

X= { x_0, x_1, ... x_n }, x_0 < x_1 < ... < x_n Y= { y_0, y_1, ... y_m }, y_0 < y_1 < ... < y_m 

And there is a function of a single integer defined as

F(delta) = CountOfItems( Intersection( X, { y_0+delta, y_1+delta, ... y_m+delta) ) ) 

That is – i add delta integer to every element of the Y and then count how many same integers are in the X and the modified Y.

And then the problem – find delta that maximizes F(delta).

max( F(delta) ), where delta is integer 

Is there some “mathematical” name for such task and optimal algorithm for this? Obviously i can use brute-force here and enumerate all possible combination – but it does not work for big n and m.

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The picture is of a Dell KB522 multimedia keyboard. I have just made a clean installation of my system with windows 10 and installed chrome with ublock. By pressing the “internet” key (the multimedia key above F1), my default browser will open. Now, this is getting tricky.

If my default browser is Edge, it will open edge as many times as I press this internet key.

If my default browser is chrome, it will open chrome one time with a blank tab but as soon as I hit this internet key a second time, chrome will navigate to delta-search dot com.

The drivers for the keyboard are the default keyboard driver from windows. Adware removal tool by TSA will find only the history entry and cache of delta-search after I hit the internet key mutiple times in chrome.

Question is, where does it come from? Is my chrome/google account the problem?

This is already happening for years. I switched my setup several times over the years, even had a complete hardware switch where I went from AMD to Intel but the kind of keyboard is the same.

Dell KB522

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We have an undirected simple connected graph with odd number of vertices. We also know the number $ k$ which is actually the closest odd number greater than or equal to $ \Delta$ . (So if $ \Delta$ is even, $ k = \Delta +1$ else $ k=\Delta$ .) i.e $ k$ is the least odd number that is greater than or equal to degrees of all vertices.

We want to find a linear time algorithm that colors the graph with $ k$ colors.

I am very new to graph coloring algorithms. I know that a greedy algorithm is actually linear time and can color the graph with $ \Delta +1$ . But I can’t guarantee I can color it with $ k= \Delta$ when $ \Delta$ is odd. Also, we probably should use all the information the question gives us. i.e using odd number of vertices somehow, but greedy algorithm don’t use this extra information.

How can I solve this?

Sending delta metrics to data warehouse

We have a requirement where our app server collects business metrics and sends them to the data warehouse daily. These records are in few millions ranging from 0.1 to 5 million for different metrics. The metrics are mainly database table records that get added, updated and deleted few number of times during the week. The metrics are temporarily stored in a sql table before being sent over AWS SQS to the data warehouse.

The flow is depicted in this diagram

enter image description here

We want to optimize our data (metrics) sending logic to send only the delta set of records i.e. send only the records that are newly added, updated or deleted from the previous day. Modifying the data collection logic to collect/query only delete is complicated hence we are thinking of applying the optimization only at the last step before the data is sent to the data warehouse.

What are some of the optimized ways that can help us to send the delta metrics to the data warehouse?

what is the difference between transition function (delta) and extended transition function (delta cap ) in finite automata

my doubt is

what is the difference between transition function (delta) and extended transition function (delta cap ) in finite automata ?

both of them when started at a state q for a string w will lead to same sate p what is the difference

is transition functions gives the transition over an input alphabet , where as the extended transition symbol gives a transition for the string w using the transition function?

On equation $\Delta \circ \partial/\partial X=\partial/\partial X \circ \Delta$ on a Riemannian manifold

Assume that $ M$ is a compact Riemannian manifold whose Laplacian is denoted by $ \Delta$ . Assume that the Euler characteristic of $ M$ is zero. Does $ M$ admit a non vanishing vector field $ X$ which satisfy $ $ (*) \qquad \Delta \circ \partial/\partial X=\partial/\partial X \circ \Delta$ $

What can be said about the structure of the Lie algebra of all vector fields $ X$ with the property $ (*)$ ?

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In the middle of a Magento 1.6.2 to Magento 2.x migration. I made a duplicate of the 1.6 store/database and migrated the data from that database to the new one. That was probably about 2 weeks ago after I sorted out all kinds of data migration problems. The duplicate 1.6 database has the tables added by the migration tool. In order to move ahead I would have to update the duplicate 1.6 database with the new data from the live 1.6 store and then do the delta migration to Magento 2. I’m not sure if this is possible. Or do I need to start over and migrate directly from the live site/database? If you have a method for this, please advise. Thanks.