The tag has no usage guidance.

learn more… | top users | synonyms (1)

31
votes
8answers
8k views

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 ...
17
votes
1answer
263k views

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 ...
15
votes
5answers
4k views

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 ...
12
votes
3answers
3k views

md5: Why is my command-line hash different from online md5 hash results?

On Mac OSX Leopard PowerPC, if I do: echo "hello" | md5 on the command line, the result is: b1946ac92492d2347c6235b4d2611184But if I enter hello into one of the online md5 hash sites like http://...
12
votes
2answers
2k views

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
11
votes
5answers
53k views

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 ...
9
votes
5answers
7k views

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 ...
9
votes
1answer
993 views

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?
8
votes
2answers
711 views

MD5 and SHA1 checksum uses for downloading

I notice that when downloading a lot of open source tools (Eclipse, etc.) there are links for MD5 and SHA1 checksums, and didn't know what these were or what their purpose was. I know these are ...
6
votes
4answers
9k views

OpenSSL hash function for generating AES key

What hash function does OpenSSL use to generate a key for AES-256? I can't find it anywhere in their documentation. $ touch file $ openssl aes-256-cbc -nosalt -P -in file enter aes-256-cbc ...
5
votes
3answers
582 views

Why does sha1sum act differently with the same input?

I'm trying to replicate the behavior of the sha1sum executable in some java code, however, in the process I've discovered that sha1sum appears to behave differently given the same input in two ...
5
votes
3answers
1k views

Best Way to Archive Digital Photos and Avoid Duplicate File Names

This problem pertains to archiving of digital pictures taken from multiple cameras. Answers here covered the general topic of the-mechanics-of-backups: How do you archive digital photos and ...
5
votes
2answers
574 views

Calculating sha256sum of a dvd

I have a burnt dvd from an iso image. I have also sha256sum of the iso image. to compare hashes, I created an iso image from the dvd and executed sha256sum image.iso, but it differs from the hash of ...
5
votes
3answers
1k views

What is a tool for getting a complete directory/file listing with detailed information including hash(es)?

Once in a while, I take a complete snapshot of my drives with a command like the following. > for %i in (%drives_hd%) do @dir %i:\/s/a/o>>File_List.txt This gives detailed information (...
5
votes
1answer
4k views

enabling LM hash in Windows 7

Is there any way to enable/convert an NTLM hash for a user account on Windows 7 to a LM hash? I know it's not secure, but I am trying to test something. Is it even possible?
4
votes
4answers
1k views

How do I verify a GPG symmetrically encrypted file?

I created an encrypted file with symmetric encryption. gpg -c 50GBfile Now I want to delete the original. Before I delete the original, I want to verify the integrity of the encrypted file. (...
4
votes
1answer
255 views

Any examples of duplicate MD5 Hashes?

I was wondering, as it is theoretically possible to have duplicate MD5 hashes, are there any known examples of this, or is it all just theoretical?
4
votes
1answer
5k views

“line length exception” in hashcat (kali linux)

I've received this line: root:$1$25A116L54$7/IbiL1ZsUyPwYBx/zuNv/ and asked to crack the password. So, I created a crack.hash file and put the following in it: $1$25A116L54$7/IbiL1ZsUyPwYBx/zuNv/ ...
4
votes
3answers
582 views

How secure is it to use a password hash of a common English word as a WPA2 key?

I have a wireless router, and I want a difficult password that is still, in a way, easy to remember. I came up with this idea to take the MD5, SHA-1, SHA-256, or whatever hash of a common English ...
4
votes
1answer
699 views

How to configure Firefox to warn or reject SHA-1 signed certificates?

Is there a way to configure Firefox either through an add-on, plugin, or other setting that will either reject or warn whenever it encounters a certificate that has been signed using SHA-1?
4
votes
1answer
217 views

What files from the /boot partition, in addition to the MBR, must be hashed in order to detect an “evil maid” attack against LUKS-encrypted Linux?

Are boot.img, initrd, and vmlinuz adequate or should the entire contents be hashed? I am not familiar enough with the Linux boot process to answer this with confidence myself.
3
votes
1answer
1k views

How to check file against a hash on windows 7? [duplicate]

How to check downloaded file against its hash (SHA-256 Hash, SHA-1 Hash, MD5 Hash) on windows?
3
votes
1answer
3k views

What is the fastest MD5 sum calculator?

I tested the speed of md5sum on a few Ubuntu 8.04 servers Pentium III 700 MHz: 52 MB/s Atom 1.6 GHz, 32-bit: 119 MB/s Core 2 (Yorkfield) 2.5GHz, 32-bit: 194 MB/s Core 2 (Yorkfield) 2.5GHz, 64-bit: ...
2
votes
2answers
284 views

Why does cygwin sha512 create different checksums depending on terminal?

I'm using Windows 7 and have both Cygwin and the ming-based Git command line tool. When I issue the command: c:\>echo -n hello | e:\cygwin\bin\sha512sum from the Windows cmd, it generates ...
2
votes
1answer
2k views

/etc/shadow in old format, where is salt stored?

In /etc/shadow I have entries such as admin:YtChlvAGYzva2:16318:0:99999:7:::. I know the original password and would like to generate the same hash somehow. However, running openssl passwd -crypt ...
2
votes
1answer
88 views

Inconsistencies on MD5 checksums

I am trying to obtain the md5 hash of a string. Said string consists of only uppercase and lowercase letters and digits. No other characters, including spaces and newlines. The string is inputted via ...
2
votes
2answers
12k views

Strongest Encryption and Hashing Algorithms Today [closed]

Basically, I want to know what the strongest (hardest to break) encryption algorithm today is. The same goes for the hashing algorithm. Let's say I pick a super-strong password too (bonus: how long ...
2
votes
1answer
706 views

Is the linux md5 password hashing considered secure?

On my RHEL6 linux is configured to use MD5 password hashing is the linux usage of MD5 for password hashing considered secure?
2
votes
3answers
107 views

How to create a SHA256SUMS file?

I can check the content of several files in a directory against checksums contained in a file named for example SHA256SUMS with sha256sum -c SHA256SUMS. Is there an easy way to generate a SHA256SUMS ...
2
votes
1answer
49 views

How can hashes be used to efficiently keep track of version changes in documents?

I have heard that open source software uses these. Are they computed on an entire file? Like if you changed one letter of Moby Dick the hash would be different? I am curious about these for keeping ...
2
votes
1answer
592 views

Checksums for Win7 installation files?

OK many thanks to the guys on Where do I download Windows 7 (legally from Microsoft)? who provided links to d/l the WIn7 .ISO images. Now where can we find a similar listing of the md5 hashes for ...
2
votes
1answer
4k views

Can Robocopy ensure file integrity?

I am trying to copy a large file, around 10G size, over Internet using Robocopy, but I am a bit concerned about the file integrity. So can I just trust Robocopy to ensure file integrity or I need to ...
2
votes
2answers
1k views

Obtain SHA256 Value for Subject Key Identifier

Using Keytool we can view the details of a Keystore with the command keytool -list -v -keystore <KeystoreName> This returns a set of values including a Subject Key Identifer ...
2
votes
1answer
1k views

Compute salt with known plaintext and hash?

I have the string that was used in a webapp with md5 hashing to come up with a hash. I also have the hash. But the md5 of the string doesn't match the hash, so I'm guessing there's a salt involved. Is ...
2
votes
0answers
95 views

Embedding index in pdf files [closed]

Are there any (free) tools for building an index of a pdf and embedding it in the file in order to speed up searching? I know Acrobat Pro has a catalog option but I was hoping for a free tool and ...
2
votes
1answer
926 views

QR Codes for Files on Google Code

When you download files from Google Code now (example), in addition to the text version of the SHA1 hash, it includes a QR code of it. The device that the file was downloaded to is the one that has ...
1
vote
3answers
330 views

Current alternative to the old CHECKSUM program

I'm looking for an application that does md5/sha hash check on specific files/folders periodically and store an index file per folder for future verification. I remember such application exist in DOS ...
1
vote
2answers
452 views

Why is an internal table of PATH directories maintained?

I was looking for what rehash command does and found this: The rehash command re-computes the internal hash table of the contents of directories listed in the path environmental variable to ...
1
vote
2answers
124 views

calculate checksum of every file that is being written to HDD

Is it possible to automatically calculate checksum of every file that is being written to HDD? My OS is Linux. I've read that btrfs stores some kind of checksums for files. Would be possible to dump ...
1
vote
2answers
132 views

Looking for a cross platform/portable program that spews out cryptographic hashes of a file

I am looking for a program, that should be source portable across Windows and Linux ( for eg. ANSI C, etc ) that generates cryptographic hashes like MD5, SHA, etc as well as CRC32 of a file/list of ...
1
vote
1answer
19 views

Rebuilding a raid 1+0 (10) system

We have a set of 8 disks that are raided together with RAID 10. Our software that rebuilds RAIDS do not allow a RAID 10 but does have a RAID 1 or a RAID 0. In theory, we wanted to drop the mirrored ...
1
vote
2answers
6k views

How to make sure a downloaded .iso matches a hash value?

I have download the .iso file as guided here and there is part that says to verify the downloaded .iso with CRC or SHA-1 hash value. Make sure that the CRC and SHA1 hash values of the downloaded ...
1
vote
2answers
3k views

Is there a way to detect encryption used on a file?

I have a small file that is encrypted and I want to see if it is a encryption method that has been broken or cracked.
1
vote
2answers
125 views

Getting Linux hashes from shadow file

I have an Ubuntu 12.04 VirtualBox machine in which some days ago I changed the password. Now when I used the machine again I've forgotten the password and can't get root access. I tried to get hashes ...
1
vote
1answer
87 views

add hash to a file using command line

I am writing a Windows batch file to copy a file from my computer to a network location, but before doing this, I need to add a hash for it using the command line. Assuming that my file is named ...
1
vote
3answers
135 views

Should I use an SSD or HDD to hash lots of data?

Purely in terms of drive life which will be better for hashing hundreds of thousands of files - SSD or HDD? Background - My HDD has files which I want to hash and compare with data in a spreadsheet, ...
1
vote
1answer
61 views

How does applications read my hashed passwords?

mpdas (last.fm scrobbler for mpd) forces one to write password hashed in md5. But if it's hashed, how does it login to last.fm? Isn't hash function one-way only?
1
vote
1answer
198 views

Is it possible to write an app that ignores the zip archive password?

I am not sure how password protected archives work but is it the programs enforcing the protection or is it the way the format works where if it's password protected, there is no way to extract the ...
1
vote
2answers
658 views

is it possible to create custom columns (such as checksum/hash column) in windows explorer?

Is it possible to create my own custom column in Windows Explorer when listing files in "Details" mode? Right now, I have: Name Date Modified Type Size Hash I would like ...
1
vote
3answers
4k views

md5sum of files in two folders

I'm trying to compare all the files in two folders via an md5sum in one command. Some like the following (bash) in Debian: $ cd ~/FOLDER1 $ md5sum ~/FOLDER2/* | md5sum -c - The idea is that the ...