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17

EaZyCode

3892

6y

Follow-up to my previous story: https://devrant.com/rants/1969484/...

If this seems to long to read, skip to the parts that interest you.

~ Background ~
Maybe you know TeamSpeak, it's basically a program to talk with other people on servers. In TeamSpeak you can generate identities, every identity has a security level. On your server you can set a minimum security level you need to connect. Upgrading the security level takes longer as the level goes up.

~ Technical background ~
The security level is computed by doing this:
SHA1(public_key + offset)
Where public_key is your public key in Base64 and offset is an 8 Byte unsigned long. Offset is incremented and the whole thing is hashed again. The security level comes from the amount of Zero-Bits at the beginning of the resulting hash.
My plan was to use my GPU to do this, because I heared GPUs are good at hashing. And now, I got it to work.

~ How I did it ~
I am using a start offset of 0, create 255 Threads on my GPU (apparently more are not possible) and let them compute those hashes. Then I increment the offset in every thread by 255. The GPU also does the job of counting the Zero-Bits, when there are more than 30 Zero-Bits I print the amount plus the offset to the console.

~ The speed ~
Well, speed was the reason I started this. It's faster than my CPU for sure. It takes about 2 minutes and 40 seconds to compute 2.55 Billion hashes which comes down to ~16 Million hashes per second.
Is this speed an expected result, is it slow or fast? I don't know, but for my needs, it is fucking fast!

~ What I learned from this ~
I come from a Java background and just recently started C/C++/C#. Which means this was a pretty hard challenge, since OpenCL uses C99 (I think?). CUDA sadly didn't work on my machine because I have an unsupported GPU (NVIDIA GeForce GTX 1050 Ti). I learned not to execute an endless loop on my GPU, and so much more about C in general. Though it was small, it was an amazing project.

rant sha1 hashing gpu computing gpu c teamspeak opencl

1
6

lxmcf

19957

6y

Another small update on my games modding stuff...

Currently building a command line tool to pack the game data, currently have a working sprite packer and am able to actually read data from the packed file and export all images byte for byte... Holy shit I might be able to actually do this!

Let me know if anyone might be interested in seeing a demo or some very unclean source code!

random game engine modding assets

5
6

Oyveloper

1592

6y

I was making software for a small handheld RFID scanner that would read specific fields from the tags. Somehow one of the fields always missed the first byte. Given that I was new to working with C I thought it was my lack of skills in the language. Spent days searching my methods, trying to find my mistake. After day two I found out I was given the wrong address to read from, and that I had just wasted two days.

rant c notmyfault rfid

2
5

7400

2757

7y

When the program exactly fit on the MCU, using up every available byte of flash. It was just a small display unit, but it felt nice that I had chosen the smallest possible controller for the job.

undefined wk65 assembly
4

SanthuLavri

35

4y

A beginner in learning java. I was beating around the bushes on internet from past a decade . As per my understanding upto now. Let us suppose a bottle of water. Here the bottle may be considered as CLASS and water in it be objects(atoms), obejcts may be of same kind and other may differ in some properties. Other way of understanding would be human being is CLASS and MALE Female be objects of Class Human Being. Here again in this Scenario objects may differ in properties such as gender, age, body parts. Zoo might be a class and animals(object), elephants(objects), tigers(objects) and others too, Above human contents too can be added for properties such as in in Zoo class male, female, body parts, age, eating habits, crawlers, four legged, two legged, flying, water animals, mammals, herbivores, Carnivores.. Whatever.. This is upto my understanding. If any corrections always welcome. Will be happy if my answer modified, comment below.

And for basic level.

Learn from input, output devices

Then memory wise cache(quick access), RAM(runtime access temporary memory), Hard disk (permanent memory) all will be in CPU machine. Suppose to express above memory clearly as per my knowledge now am writing this answer with mobile net on. If a suddenly switch off my phone during this time and switch on.Cache runs for instant access of navigation,network etc.RAM-temporary My quora answer will be lost as it was storing in RAM before switch off . But my quora app, my gallery and others will be on permanent internal storage(in PC hard disks generally) won't be affected. This all happens in CPU right. Okay now one question, who manages all these commands, input, outputs. That's Software may be Windows, Mac ios, Android for mobiles. These are all the managers for computer componential setup for different OS's.

Java is high level language, where as computers understand only binary or low level language or binary code such as 0’s and 1’s. It understand only 00101,1110000101,0010,1100(let these be ABCD in binary). For numbers code in 0 and 1’s, small case will be in 0 and 1s and other symbols too. These will be coverted in byte code by JVM java virtual machine. The program we write will be given to JVM it acts as interpreter. But not in C'.

Let us C…

Do comment. Thank you

random beginner advice encouragement suggestions are welcome basics comments oops java

6
3

lorentz

15122

4y

I just realized why 4 bits make a nybble. I love the naming conventions in this field.

random nybble naming small byte

2

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