Questions tagged [md5]

MD5 is a hash function that is no longer considered secure from a cryptographic point of view. Therefore, it should only be used for backward compatibility.

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Avoiding MD5 collision with secondary partial hashes

I am trying to design a VCS like program that determines if the files are the same by comparing their MD5 hashes. Then I read about MD5 collisions here, and I wonder if I can work around that by doing ...
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how high is the possibility of getting a hash collision in text files?

Just for an example, let's say I downloaded "the adventures of tom sawyer" from gutenberg in .txt file format and saved it to my usb thumb drive. And as you can see, usb drive is not an ...
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How strong if I combine two hash functions, such as MD5(SHA256(input))?

If I try to do MD5(SHA256(input)), what is the strength of this so-called double hashing approach? Is it as strong as SHA256, or as strong as MD5, or as strong as ...
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How blueimp JavaScript-MD5 works?

I have made some progress on the MD5 avalanche problem, https://github.com/221294583/crc32 It is said that CRC32 realizes avalanche through recursive XOR of polynomials and original values at the same ...
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Matching accounts across multiple data leaks via their hashed passwords

I've heard about several instances where OSINT researchers were able to match user accounts from multiple data leaks purely based on their hashed passwords, assuming accounts had the same password on ...
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How easy is it to fake a file hashed with three functions, CRC32, MD5 and SHA-1?

File-A is hashed with CRC32, MD5 and SHA-1. How easy is it to create a fake file-B that has the same hashes of file-A? CRC32, MD5 and SHA-1? Can an average PC with a GPU calculate a triple hash ...
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Is it possible to have a hash in UUID form that ends with 16 characters instead of 12?

You may know how sometimes a hash in a URL may be in UUID format, which consists of groups of hex values separated by hyphens. In UUID format, I have come to learn that this hash takes the form: 8-4-4-...
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Can someone please explain the "secret" and the "data" in the MD5 hashing algorithm?

I've been studying the MD5 hashing algorithm, and there is something that I just don't understand yet. They say that the server holds some sort or "secret" and that it appends some sort of &...
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Padding and the MD5 algorithm

In MD5, if M=100, how can we perform padding on it and how many blocks are needed in each round? These are general questions for understanding padding and rounds.
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Finding the cleartext password given its MD5

Given powerful GPU and PC hardware, is it realistic to recover a password in a few hours given a cleartext's MD5? Max chars are 95, and the maximum length of the password is 15 characters.
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Is it possible to exploit MD5 weaknesses to create an artificial collision for a password?

If it is possible, could an attacker create a collision for an MD5 password in a database? Could they look at an MD5 hash output and figure out data that creates the same MD5 hash?
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Two Different Ciphers with Same MD5

I was wondering if someone could help explain md5 collision abit better. I found this resource: https://www.mscs.dal.ca/~selinger/md5collision/ where they provided an example of where two cipher texts ...
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Use slow hashing to reduce digest size?

I have seen this question on MD5 replacement for 128 bit digests. It is said numerous times that having a 128 bit digest is impossible today because finding a collision would only require $2^{64}$ ...
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MD5 Algorithm is nonlinear?

https://iopscience.iop.org/article/10.1088/1742-6596/978/1/012116/pdf Each operation performs a nonlinear function on three of a, b, c,and d. ...
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Recreate RC4 Stream cipher

I'm trying to learn how to go about cracking RC4 ciphers (nothing illegal, its an old, i.e., not active challenge for a job application, so no cheating). I have nine md5 hashes with their own ciphers. ...
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If you have two inputs of the same length, are there theoretically collissions in both MD5 and SHA-256?

Can there be two messages M, M' both of the same length such that both MD5(M)=MD5(M') and SHA-256(M)=SHA-256(M')? Let's compare two files: if they have the same length, they are candidates for having ...
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Can we build two messages with same MD5 but different size? [duplicate]

Can we build two messages with same MD5 but different size? I researched MD5 collisions, but everything I found targets messages of the same size.
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Attack MD5 with limited input and partial information

If I know that MD5 input is limited to a character set. can I find any information on the input based on the output? example: input consists of 16 character from list of [1,2,3,4,5]. question: based ...
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Will repeatedly applying a hash function to the prior result visit all possible hashes? [duplicate]

If one were to take a message, say "Hello world!", and compute the MD5 hash: 86fb269d190d2c85f6e0468ceca42a20 Then, taking the MD5 hash of this, and repeating that procedure: ...
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How are SHACAL-2 ciphers calculated?

I am trying to learn about the underlying functionality of the different hash functions (currently SHA) and I'm pretty stuck even after watching a Stanford video about it. One method of hashing is by ...
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Security implications of using the low-order bits for Merkle–Damgård message length

According to RFC 1321 § 3.2 (MD5), the length of the message ($b$) is encoded as $b \bmod 2^{64}$: ...
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Can I clone MD5 hash to a different file? [duplicate]

one.ttf (3f67f2feb32a72cf4b90c767eb43aa52) two.ttf (8880bae64dc9e6ba22446f789d09d3d7) I want to set one.ttf md5 hash to two.ttf It is possible? Like this one.ttf (3f67f2feb32a72cf4b90c767eb43aa52) two....
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Changing a bit in IV of MD5

It is obvious that changing even one bit in data or IV (initialization vector) will change the hash value a lot. I want to know if, for example, changing a single bit within the $IV$ in MD5 can be ...
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Are the common hash algorithms already dead? [closed]

I have one honestly question: How can we are so confident with the use of the common hash algorithms (nowadays there are so many pages with cracking tools: crackstation, gpuhash, etc) ? Are we lost ...
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Is this password-cracking challenge possible?

Taking a graduate computer security class, part of our current assignment is to crack 50 Unix md5crypt password hashes, due on Thursday, October 8th (in eight days.) I've managed to crack 49 out of ...
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Is the MD5 algorithm only useful for bytes, rather than bits?

The MD5 algorithm is designed to accept a message of any length and produce a 512-bit message digest. Because of the way it pads the original message, by adding a 1-bit then a number of 0-bits, the ...
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Avoiding collisions by combining MD5 and SHA-2

It is often suggested that hashing of long character columns can be used for indexing in databases, but the possibility of collisions is an issue for Unique indexes. Whilst I know that both MD5 and ...
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The length extension attack and security on length shortening of a hashed message by one byte

MD5, SHA1, SHA2 are vulnerable to length extension attacks Wikipedia:Length extension attack. Could is also be possible to generate $H(\text{message}[1..n-1])$ from $H(\text{message}[1..n])$ if I know ...
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How can a collision attack using MD5 be used to break WOTS

It is stated in Winternitz One time signature security that MD5 is not safe for Winternitz due to collision attack. Given that WOTS generates multiple, say 32 private keys then hashing them a number ...
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Security implication of concatenating two hashes using different algorithms

Background Hashing files is an expensive thing for CPU. I am tasked to write a secure digital signature scheme. For that, I decided to check the integrity of files using Hash/Digest. To be more secure,...
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Would increasing the "target space" of MD5 collisions make it significantly easier to find a collision?

This is tangential to this question, which asks about generating a file to match an exact MD5 hash. My question is if it would be significantly easier to generate a file that is "within X digits ...
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Combining Hashes - NTLM and SHA

i have been recently learning about different types of hashing and the encryption/decryption methods of such hashes. Im currently trying to find the preimage of this hash i have been given as a ...
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If two hosts are using a transparent IP level authentication and encryption, is their communication subject to both MITM or replay attacks?

Encryption process for any outgoing packet to the specified "remote IP": -original payload P is encrypted (the bytes after the IP header) using RC4 with the preestablished key ...
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Length extension attack in the middle help!

is it possible to insert the command that you want to execute in the middle of the md5 hash token already known?
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How to create two partly similar plaintexts with same MD5 hash value?

The problem I'd like to solve looks like this: There are two plaintexts which differ in length and letters, but contain a few common strings. The first few words and the last few words are the same, ...
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How is the MD5 digest calculated in BGP?

The RFC is very superficial on the implementation details. What is the injective function being used? RFC (ietf) MD5 digest is produced by applying the MD5 algorithm to these items in the following ...
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MD5 hash: retrieve an element of a source string

Suppose you have a string, precisely an MD5 hash string, which basically it is computed in the following way: "element1:element2:element3" So, in order to get ...
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Formula of function in MD5 algorithm

As i read MD5 have many complex formulas, example: $k_i := \lfloor \space| \sin(i + 1) \times 2^{32}| \space\rfloor$ My question is why use sin(), how about cos() or tan() or something like that. ...
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What is the use of encoding a hash output?

In many applications, the MD5 algorithm is used which produces a 128-bit output which is represented as a sequence of 32 hexadecimal digits. This output is further encoded using a base62 or base64 ...
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CHAP vs EAP-MD5

I started studying EAP authentication framework and I don't understand why was the EAP-MD5 developed. Why not just use the CHAP protocol ? To me they seem the same. Can you explain to me ?
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Can the OpenSSL random number generator be considered cryptographically secure? [duplicate]

The OpenSSL Random Number generator documented here uses an OS-provided entropy source coupled with a MD5 hash function. Does it impact the quality of randomness to use a broken cryptographic hash ...
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Storing email addresses in plain sight

What would be the best approach for storing a list of hardcoded email addresses in plain sight (in a public JS file or such)? The site is pretty low-key, for a small community of friends. Starting ...
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Most efficient way to break md5?

if you know the result of a hash, for this example the resulting hash is: ec664d1d65fd8a58c59b337b11c37a4d And you also know the hash has been made like this: <...
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Are there two known ASCII-only strings which have the same MD5 hash value?

Up to now, the pairs of strings that create an MD5 collision that have been discovered all contain non-ASCII (binary) characters. Are there two known ASCII-only strings which have the same MD5 hash ...
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Is it feasible to get a hash collision for CRC32, MD-5 and SHA-1 on one file?

I'm aware that individually, each has its weaknesses (especially CRC32), but is it feasible that a file could be created to falsely match all three?
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Does a hash function have a Upper bound on input length?

I came across this Answer stating (just a line from the answer):- The input space is "infinite" and thus it has an infinite amount of values that will collide into a single hash And in the ...
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For a hashing function like MD5, how similar can two plaintext strings be and still generate the same hash?

When I say similar, I'm referring to the Hamming distance, the Levenshtein distance, or a similar string distance metric that measures how similar or dissimilar two strings are. For instance, are ...
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Suitable 16-bit checksum?

I am writing a toy1 transport protocol and I am trying to implement a feature whereby: A 16-bit checksum is included in every packet. This checksum can be extended to be 48-bit if the data is large, ...
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Does it matter if I publish only publish good or bad MD5 hashes after recovering from a hack?

(This question is a follow-up from another question I asked about MD5, which is why I'm insisting on using MD5 in this question as well) My imaginary Linux distribution, Sushi Linux has had a big ...
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Is there really no use for MD5 anymore?

I read an article about password schemes that makes two seemingly conflicting claims: MD5 is broken; it’s too slow to use as a general purpose hash; etc The problem is that MD5 is fast I know that ...

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