Questions tagged [hash-function]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
2
votes
2answers
431 views

Can one reverse a hash with partial plaintext knowledge?

First off, please forgive my ignorance because I am not as well versed in cryptography and mathematics as I would like to be. I may say something obviously wrong/dumb; please point it out! Is there ...
3
votes
1answer
521 views

Collision Attacks, Message Digests and a Possible solution

I've been doing some preliminary research in the area of message digests. Specifically collision attacks of cryptographic hash functions such as MD5 and SHA-1, such as the Postscript example and X.509 ...
2
votes
1answer
340 views

Getting started with Hashing for Information retrieval

I recently finished my bachelors and now work on Cross-lingual language search. I want to get started in hashing and see how they are useful in information retrieval. (Yes, I know what hashing is), ...
2
votes
2answers
8k views

How to compute Integer Hash of a string [closed]

Is it possible to convert a string to a unique number. Similar to any hashing algorithm (MD5, SHA-1 and SHA-2), I want to compute a unique integer value for an arbitrary length string, which should ...
11
votes
1answer
730 views

Do 'reflexive' hash algorithms exist?

Is there a class of hash algorithms, whether theoretical or practical, such that an algorithm in the class might be considered 'reflexive' according a definition given below: hash1 = algo1 ( "input ...
9
votes
2answers
930 views

What is the optimal data structure for a tree of maps.

I'm looking for a data structure, that is basically a tree of maps, where the map at each node contains some new elements, as well as the elements in its parent node's map. By map here I mean a ...
10
votes
2answers
799 views

Hashing sets of integers for inclusion testing

I'm looking for a hash function over sets H(.) and a relation R(.,.) such that if A is included in B then R(H(A), H(B)). Of course, R(.,.) must be easy to verify (constant time), and H(A) should be ...
3
votes
1answer
259 views

How is DHT different than regular hash tables in context to data/node lookup?

How is DHT different than regular hash tables in context to data/node lookup? This (introduction, 3rd paragraph) paper says: First, in addition to the insertion and deletion of items, DHTs must ...
5
votes
2answers
720 views

How is rebalancing of DHTs handled in case of failure or addition of new node?

I am reading about Dynamo-like DHT data storage applications like cassandra and project voldemort. I was curious, say: A new node is added to the cluster (since all the nodes are full) then the whole ...
26
votes
3answers
14k views

What is the difference between a second preimage attack and a collision attack?

Wikipedia defines a second preimage attack as: given a fixed message m1, find a different message m2 such that hash(m2) = hash(m1). Wikipedia defines a collision attack as: find two arbitrary ...
16
votes
1answer
559 views

Why is it important that the secret is at the end when signing with MD5?

it is often said that when using the MD5 algorithm to sign some arbitrary information, the shared secret has to be at the end. Why?

1
2