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Questions tagged [hash-collision]

a situation that occurs when two distinct pieces of data have the same hash value, checksum, fingerprint, or cryptographic digest.

See also the wiki tag.

233 questions
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One way hash with variable length alphanumeric output

I need to one way hash alphanumeric + special chars(ascii) strings of variable length (10-20 chars). The output should be of variable length but max 25 chars long, alphanumeric and case insensitive. Also I do not want to produce collisions so I need…
Chris L.
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How to find a specific element in an array when using quadratic probing?

I have two inputs (example): "Smooth Criminal" and "Billie Jean", that return the same index key, when run through a hash function. In the array[], i want to save the path to the songs MP3 file on my harddisk. Let's say they both return 0 as index…
Kenci
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Likelihood of Collision

I want to hash an internal account number and use the result as a unique public identifier for an account record. The identifier is limited to 40 characters. I have approximately 250 records with unique account numbers. What is less likely to…
Michael Starkie
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Probability of New Hash Collision, Conditional on No Current Collisions

I'm trying to understand the probability of collision of new hashes, given no collisions in the existing hash table yet. For illustration, let's say I have a table where I store hashes of each row. The table currently has 1 billion rows There are…
Chandler Sommerville
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Can 2 files have "same" "many" "different" types of hash?

I know that hash collision is possible with large number of files. But i want to know if 2 files can share "many , different" types of hash. I have 2 hashes SHA256 and BLAKE256 (Both will result in different hashes) For example: File A have…
Akash
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Is mixing uuidv4 and uuidv5 collision safe?

I have a key value store where rows are indexed by uuid. For some of the keys I generate the key with uuidv4. For some of the other keys I generate the key from two other uuids from that same key value…
david_adler
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How to find a collision of first 56 bits for MD5(MD5(x)) for input data with the same prefix?

I have a code to find the collision of the first 56 bits of the hash function: md5(md5(x)) (using the Floyd algorithm to find cycles). The script returns two strings (hare, tortoise) for which a collision occurs. How to modify this script to return…
Jarosław Wieczorek
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Efficiently run hash collision checker

I'm trying to run the ff.
IMB
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In RFC4122 there is a phrase "A UUID is 128 bits long, and can guarantee uniqueness across space and time"

RFC4122 what does phrase uniqueness across space and time mean and please explain.
Madhukar Moogala
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Can I use GetHashCode without Equals?

Maybe I don’t understand something. No, I definitely don’t understand something. There is a custom class with two int type properties. Overriding the GetHashCode method, I want to use both of these properties as the basis for obtaining the hash…
Konstantin
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Can two features in two different namspaces collide while hashing in vowpal wabbit?

Do all the namespaces have the same hash space or does each namespace have an independent hash space? Also, if they do have independent hash spaces, do they create new hash spaces for interaction features?
sameershah141
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HashMap hash function- Binary operator

I was going through the source code of HashMap, but the binary operators confuses a lot. I do understand the general purpose of below, fair distribution and bring hashCode within the bucket limit. Can someone explain the comments here and what is…
Deepak Kumar
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Is deletion less costly if linear probing is employed than in the case of separate chaining?

For hashtables, as is familiar we first compute a hashfunction. Then we need to take care of collisions; cases when two or more keys to be inserted hash to the same index. Two methods of doing this include separate chaining and linear probing. My…
0jnats3
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I'm using .hashCode() to create hashes. Is there a library to perform double hashing in Java to resolve collisions?

As a homework problem, I'm trying to create an implementation of a hashmap using an array. I'm using .hashCode() to create the hash, and I need to find a way to resolve collisions. I thought of using double hashing, but I can't find a way to do…
EnterPassword
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Collisions when using FARM_FINGERPRINT in BigQuery to generate hashes for Surrogate Keys

I was wondering if anyone is able to provide some insight into the chances of collisions when using FARM_FINGERPRINT in BigQuery to generate INT64 hashes to be used as Surrogate Keys on tables? Going with a normal UUID increases storage of the key…
Twist
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