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Questions tagged [hashing]

183 questions
795
votes
30 answers

Is there a built-in checksum utility on Windows 7?

Is there a built-in checksum/hash utility on Windows 7?
user64996
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44
votes
12 answers

sha1sum for a directory of directories

sha1sum ./path/to/directory/* | sha1sum the above was posted as a way to compute a sha1sum of a directory which contains files. This command fails if the directory includes more directories. Is there a way to recursively compute the sha1sum of a…
Ocasta Eshu
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40
votes
6 answers

Is there an Excel function to create a hash value?

I'm working with a number of data lists that are keyed by document name. The document names, while very descriptive, are quite cumbersome if I need to view them on (up to 256 bytes is a lot of real estate) and I'd love to be able to create a smaller…
dwwilson66
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39
votes
4 answers

How to take sha256sum of file and compare to check in one line?

I keep on finding myself wanting to download and check the integrity of the download immediately in a script, but I haven't been able to find the right incantation of…
tarabyte
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35
votes
8 answers

Can a file be maliciously changed in a way that maintains its original SHA-1 Hash?

According to this article, and many others, SHA-1 is not secure. In my case, I am not concerned about passwords or digital certificates. I am concerned about file integrity. Is it reasonably possible for a file (e.g. an ISO image or executable file)…
misha256
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28
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4 answers

Why is my command-line hash different from online MD5 hash results?

On a Mac OS X v10.5 (Leopard) PowerPC, if I do: echo "hello" | md5 on the command line, the result is: b1946ac92492d2347c6235b4d2611184 But if I enter hello into one of the online MD5 hash sites like http://md5online.net/, I…
pellea72
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23
votes
3 answers

How can zero byte files generate a hash value?

How can a zero byte text file generate a hash when hashed with sha1sum, sha256sum etc? What data are the programs hashing to generate a hash value? Ta
Gizmo_the_Great
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23
votes
1 answer

How do I recover the password of a RAR file on Mac OS X?

I'm running Mac OS X 10.6.2 and have been handed a couple of old files that need to be extracted. Old backups or finances or bills I believe. They are RAR files, and password protected. Is there a way to extract the hash from these files so I can…
Josh K
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22
votes
3 answers

Get the fingerprint of an existing SSH public key

This Question asks about getting the fingerprint of a SSH key while generating the new key with ssh-keygen. But how does one get determine the fingerprint of an existing public key in a .pub file? ➥ How to get: SHA256 hash of an existing…
Basil Bourque
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19
votes
6 answers

How to compare parts of files by hash?

I have one successfully downloaded file and another failed download (only the first 100 MB of a large file) which I suspect is the same file. To verify this, I'd like to check their hashes, but since I only have a part of the unsuccessfully…
sinned
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18
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5 answers

Why is MD5 still used heavily?

MD5 seems to have well documented vulnerabilities and yet it remains widespread in its usage. Does anyone have any reasons for it remaining a viable option when other alternatives (e.g. SHA-2) seem to be more robust?
David in Dakota
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15
votes
7 answers

How can I generate an MD5 sum for a folder on Windows?

There are several posts about generating MD5 sums for files and/or folders on various Windows platforms. However, none of these worked for me. I tried: Windows CertUtil: CertUtil -hashfile myFileName MD5 returns "Access is denied" on all folders…
Klangen
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14
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6 answers

Safe way to verify that a Microsoft ISO has not been tampered with

I'd like to make sure an ISO (disc image) I have for a Microsoft Windows 10 OS is genuine. The way I usually do this with any file is by computing a hash of the file and comparing the result to the expected hash (typically provided by the software…
BeetleJuice
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13
votes
1 answer

Which file system automatically stores hashes of files?

Which file system automatically computes and stores hashes of files and later checks them at access to detect corruption?
Adrian Panasiuk
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12
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5 answers

For websites, is your password's hash computed on the client or the server side?

I was wondering if passwords' inputs are "converted" locally on the client/web browser side or on the server side. I'm pretty sure it's on the server side, but in that case it brings a concern to me: that means you are sending your password to a…
Ozwel
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