Questions tagged [hashing]
The hashing tag has no usage guidance.
30
questions
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0
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59
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Weird behavior of repeated Mod of Hash
I was working on a wolfram challenge problem involving Hash, and I noticed some very odd behavior. The problem is to create a function ...
- 3,453
1
vote
1
answer
81
views
How to remove/ (avoid) the # sign in "Solve" output [duplicate]
I am trying to find an equation of A with variable B using the Solve function.
I have the first derivative of firm A's profit with respect to location a, which is equal to zero.
I have the first ...
- 11
6
votes
4
answers
331
views
Using multiple hashtags in NestList
Are multiple hashtags allowed in NestList usage? If yes, how to implement it?
Example,
f[{x_, y_}] := {x + y, x - y};
NestList[f, {100, 75}, 5]
My attempt,
...
- 883
4
votes
1
answer
106
views
Search speed of downvalues when indexing with strings
I'm writing a lot of print functions for different parts in a package and at the moment am using something like
myprint[ identifierString_String ][ data_ ] := ...
...
- 1,470
4
votes
2
answers
114
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From list to unique ID number AND back
If I have a series of list of the form $L_k=\{a_1, a_2,...a_n\}_k$ with $-4<a_i<4$ and $a_i\in\mathbb Z$, then I can make a unique ID number for $L_k$ using ...
- 964
2
votes
1
answer
100
views
Unique matrix ID and fast checking
I have the following problem :
I have a programm which can generate a lot of 3x3 matrices whose elements take integer values in [-3;3], example :{{1,2,3},{-3,0,-2},{1,1,1}}.
Each time my programm ...
- 964
8
votes
1
answer
515
views
How to define your own hash type?
Currently Mathematica offers support of a bunch of different hash algorithms. I would like to add my own to the list. In this way I can still use the function Hash[]...
- 175
3
votes
1
answer
148
views
User implemented SHA-1 isn't outputting correct hash
EDIT: I'm actually Thinking the issue is in the initialization phase, where we pad the message with 1's, 0's, and the message ...
- 445
1
vote
0
answers
52
views
Keyed Hash for HMAC SHA256 [duplicate]
I'm trying to use AWS REST API's (because I can't rely on AWSLink`). The sample C# code from Amazon uses this a lot:
...
1
vote
1
answer
86
views
Problem passing argument in hash table from global context to a module
I was experimenting with passing arguments via a hash table to a module. Found a very strange result. When I pass a function to be plotted inside the module, it comes out empty.
Yet all argument ...
- 137k
18
votes
2
answers
1k
views
How has Hash changed in 11.3?
There are already few topic related to Hash[_String]:
How does Hash calculate hash for strings?
Incorrect calculating Hash SHA256
But it looks like changes are ...
Kuba♦
- 136k
1
vote
2
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312
views
Incorrect calculating Hash SHA256
At the moment I'm using version 11.2. A few days ago, after an update in my programs, I found errors. It turned out that the new version incorrectly computes the hash. I'm using method SHA256. And ...
- 516
18
votes
1
answer
545
views
HMAC correct on 11.2 but wrong and different on 11.3 running same code
If you run this code on 11.2
...
- 1,289
8
votes
1
answer
438
views
How does Hash calculate hash for strings?
I have this code
Hash["a","SHA"]
Hash[ToCharacterCode["a"],"SHA"]
and I was expecting to get the same result, but somehow it is different.
My question is: how ...
- 531
4
votes
2
answers
170
views
J/Link HMAC Base64
I am trying to recreate a Java algorithm in Mathematica. It is taking a key and signing a message using the HMAC and SHA256 algorithm.
The Java code for which I am basing it off is here
I have ...
- 1,289
3
votes
1
answer
338
views
Using Mathematica how can I simulate the MD5 or SHA encryption of a userid and password performed by htpasswd on Apache?
htpasswd hashes a user's password using the userid. Thus this generator takes both userid and password as inputs and then it outputs a line for inclusion in the <...
user51827
5
votes
5
answers
1k
views
Help converting geohash string to latitude, longitude?
I'm having difficulty converting a geohash string to latitude and longitude with Mathematica and wondered if I'm missing a built in function that already has the functionality available?
(I'm still ...
- 263
3
votes
1
answer
1k
views
API HTTP Request Signing using base64 encoding/decoding and HMAC (Cryptocurrencies Exchange, GDAX)
I am trying to access the GDAX API private methods which can be seen here, GDAX Documentation
There is some great Python code that does it that I am trying to recreate in Mathematica. That code can ...
- 1,289
0
votes
0
answers
231
views
Algorithm that will trim a unique ID number and produce a shorter unique ID
I have a unique ID number with 2^128 magnitude length (128 bits). This means ~3.4e+38 which is quite large that my actually needs, spending valuable time in a transmission protocol.
There is a ...
- 101
4
votes
1
answer
222
views
HMAC-SHA512 in mathematica and $SystemShell differences
Hi I'been trying to rebuild the script to get hmac-sha512 but could not get it work
...
7
votes
2
answers
174
views
Hash reliability for uniqueness?
I have an algorithm that produces certain entries of data and appends them to a list myList = {};. For example, after five iterations the list might look like:
<...
- 11.9k
3
votes
1
answer
227
views
Read RDF N-Triples and replace them with a hashed index 'on the fly'
I want to process a 181GB uncompressed RDF N-Triples file. You may download a small sample file (4KB) and read the file line by line.
...
- 1,291
13
votes
3
answers
3k
views
How to calculate SHA256 of a number, not string
Mathematica always interprets the input of the Hash function as a string. I would expect this:
...
- 427
1
vote
0
answers
106
views
Is this a serious flaw in Mathematica's default hashing algorithm
Below, I define two expressions X and Y (which arose in the wild!) such that not only
...
- 1,251
8
votes
1
answer
458
views
HMAC implementation in pure Mathematica
I am trying to implement the HMAC algorithm in Mathematica. The algorithm is a relatively simple way of signing messages with a key.
Here is some pseudocode from Wikipedia:
My attempt:
...
- 8,442
2
votes
0
answers
175
views
When does Mathematica automatically use dispatch tables for function evaluation? [closed]
I've read the documentation for Dispatch, and it says:
Lists of rules produced by assignments made with = and := are automatically optimized with dispatch tables ...
- 743
5
votes
2
answers
575
views
Why should we make sure the calculated MD5 is of length 32?
I see when people write code on calculating MD5, (even in the documentation), they write like this:
IntegerString[Hash[something, "MD5"], 16, 32]
But I think ...
- 7,851
6
votes
2
answers
1k
views
Why does the hash of a file differ from the hash of its content?
FileHash doesn't allow arguments like
FileHash[file,{"CRC32","MD5"}];
A solution could be:
...
- 1,843
29
votes
2
answers
1k
views
Default behaviour of Hash[expr] and hashing in different versions of Mathematica
In different versions of Mathematica, Wolfram silently changed the behaviour of Hash when the algorithm is not specified explicitly
...
- 528
15
votes
3
answers
1k
views
Why does Hash return different values in Version 7?
This function does not work correctly for me. The generated Gravatars do not match the ones actually produced by using the corresponding address.
The problem was traced to differing output from the <...
- 270k