hft
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How do unzip programs check if the password is correct?
37 votes

It depends on the specific zip crypto algorithm. For example, the original ZIP specification used the password to initialize a set of three 32-bit decryption keys. Then the ZIP header (12 random ...

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How to investigate an unknown 1.5GB file named "sudo" in my Linux home directory?
25 votes

Does anybody have any tips on how to proceed investigating this file? Since file doesn't recognize the "data" as an executable, it will be difficult to try to analyze dynamically (by running it) ...

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Permanently erasing a file
17 votes

So the question is: If you overwrite a file's data with, let's say, just using WriteFile Win API to overwrite all data with zeros, will that become unrecoverable? Don't use the WIN API WriteFile to ...

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Strongest file encryption available
16 votes

I know nothing about cryptography. How do we encrypt a file in strongest (emphasis added) possible way such that we can access them some years later. I prefer that it should be fairly resistant from ...

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Trojan "Win32/Tnega!MSR" found by Windows Defender - aliases used by other antiviruses?
Accepted answer
12 votes

Does anyone here know the alias used for "Tnega!MSR" by other antiviruses, or can point me to a resource so I can find it out myself? Use the VirusTotal website. They have a lot of ...

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CVE-2018-10933 - Bypass SSH Authentication - libssh vulnerability
11 votes

Do Operating Systems like Debian, Ubuntu rely on libssh for SSH and if they do does that mean every server exposing SSH is vulnerable to this attack? The issues may arise with applications that use ...

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How likely is a collision using MD5 compared to SHA256 (for checking file integrity)?
Accepted answer
10 votes

I wonder how much safer is the use of the SHA256 hashes for integrity checks? Note: Consider the file content as random input (no attacks) Based on your note of "no attacks" it seems to me ...

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Security of hashing and encryption algorithms for 30 years
9 votes

Assuming a product shelf life of 30 years... As commenters have pointed out, this is an unreasonably long expectation for the shelf life. what is the recommendation/suggestion for hashing or ...

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How can salted passwords work if you don't "keep the salts in the system"?
9 votes

In this report on the recent ParkMobile breach, the article has this comment from the company: “You are correct that bcrypt hashed and salted passwords were obtained... Note, we do not keep the salt ...

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Can there be a virus that uninstall itself?
9 votes

Is there possible situation where a file contains malicious codes and after the code is executed, the virus attach itself to another file and delete the malicious code from the file where it comes ...

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When I sign a git commit, what is my signature actually based on?
Accepted answer
6 votes

I took a look at the function "commit_tree_extended" in the git source code for the file "commit.c" (e.g., in this blob). Based on reviewing this function, when you sign a commit ...

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Can your internet provider monitor your data (passwords, etc?)
Accepted answer
6 votes

Was typing in my password into an HTTPS website ... When I type in Username123 Password123 Can the internet provider see it just like that? Typically, no. The application-layer data you mentioned (...

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Encrypt folder on Linux that can only be decrypted on that specific OS and device
6 votes

Suppose I want to give a computer to someone that runs an application. I want to avoid that the program can be copied to another computer or be tampered with. There are commercially available ...

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How do I decrypt a .dmg image if I know details about the password?
6 votes

The answer/thread you linked to stated (regarding the brute force tool): Practically, this will bring you absolutely nowhere, unless the .dmg was encrypted with an extremely naive password (like '...

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Static detection of PE
5 votes

Can PE file have two or more executable sections? Yes, it can, but it is atypical. Normally the compiler will make a section named ".text" with the correct permissions for executable code. But PE ...

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Alternatives to cryptographic signatures
Accepted answer
5 votes

My overall goal is to be able to verify the message is valid, and retrieve the message (does not matter if it's visible or not) with the smallest overhead possible, with both endpoints under my ...

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Is this code vulnerable to Reflected XSS?
5 votes

Any ideas if this code is vulnerable and how can it be exploited? As mentioned in the comments, this code could be vulnerable to CSS injection. For example, if the URL looks like: http://some....

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Is there any risk from attempting ssh authentication to a rogue server?
5 votes

In the comments OP separated his original question into two different questions, the first of which has already been answered, as pointed out in the comments. Question 1: can client public key be ...

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Replacing cached domain credentials in SECURITY hive
5 votes

Now my question: Is it possible to replace the cached password hash of a domain > user with that of a known password, in order to then reboot the system and log > in with the known password Yes, this ...

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Will data be seen if an insecure packet is sent to an offline server?
5 votes

If the website is not listening on port 80 and the address http://website.com (or whatever URL, assuming website.com here means the domain that is listening on port 443 and not listening on port 80) ...

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Cryptographic hash function vs. non-cryptographic hash function examples and compare
Accepted answer
4 votes

An example of a cryptographic hash function is SHA256. An example of a non-cryptographic hash function is CRC32. A cryptographic hash could be used, for example, for a cryptographically strong Message ...

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Would a firewall contain an explicit allow rule at the top?
4 votes

Someone in an interview today told me every firewall has two rules: explicit allow at the top and explicit block at the bottom. Form the way I've always understood things firewalls are normally ...

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Determining the entropy of a string if each character has a slight bias
4 votes

My concern is that my character selection is biased. Because 10 doesn't divide evenly into 256, the first 6 VALID_CHARS are slightly more likely to occur. The secret space is 10^32, but my generated ...

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Is it too late to encrypt my already used USB drive?
4 votes

Is it too late to encrypt my drive even if files are on there already? You can "turn on" Bitlocker To-Go to encrypt the files/folders already on the USB drive. However, as the other post indicates, ...

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Most reduced types of DoS attacks
Accepted answer
4 votes

What about layer 4 and is my reducing attempt accurate? Your reducing attempt appears to group levels 3, 2, and 1 together and group 7, 6, and 5 together. This is not entirely accurate since denial ...

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SHA256 Encrypting with Value
Accepted answer
4 votes

Is it possible to encrypt a value (such as "hello world") with itself ("hello world") [...] Is it possible, but not recommended in practice (see below). using an encrypting technique such as ...

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Selling HDD - wiping
4 votes

Many different types of hardware write-blockers (e.g., wiebetech brand) will identify the HPA and DCO and remove them for you if you choose. Once the HPA and DCO are gone then wiping the disk, e.g., ...

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How many rounds of Bcrypt to use for security equivalent to SHA256?
3 votes

We regularly use 10000 iterations of SHA256 for hashing passwords. If we want to have similar security, how many rounds/work factor should we use when hashing passwords with bcrypt? It depends on ...

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What does it take to brute force 42 hex characters
Accepted answer
3 votes

What does it take to brute force something like this 00f54a5851e9372b87810a8e60cdd2e7cfd80b6e31 What you have shown above is 42 hex characters, which is 21 bytes, which is 168 bits. Therefore, if you ...

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Who is at risk from the PrintNightmare RCE?
3 votes

All the news articles describing the RCE are implying that any internet-connected computer running Windows is at risk. First, what you have stated here is not true. The article that you yourself ...

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