DES-X Encryption slow / Help needed

[NON]

Originally Posted by eychei

Hi everyone,

I did write a small vb.net program to encrypt and decrypt DESX.
Its actually nearly the same as DES but with an additional input and output XOR with two extra keys.

Attachment 10479

So when I decrypt files it easy really fast taking around 10sec for 100mb.
This is because I can decrypt the complete file first without needing to go from one block to the next.

But when I encrypt files I need to chain 8 byte sized chunks in serial.



So I tried different approaches in appending the ciphertext at the end to a bte array so i can write it to file afterwards.
It does not change in speed if I use array.copy / concat or for loop copy.
I also tried with creating 4-8 parallel threads. While this reduces the time needed for encryption, it is still slow for very big files.


How can I increase speed for the encryption algorithm? Hope someone has a solution.

Thx.

-e

You can write native code instead of the .Net code. Will be much faster. At least, write the time consuming parts of the code in native. You can use the pre-written libraries available on internet. No need to create your own. Much faster.

[chants]

Originally Posted by Gregory Morse

You can write native code instead of the .Net code. Will be much faster. At least, write the time consuming parts of the code in native. You can use the pre-written libraries available on internet. No need to create your own. Much faster.

In the future if you are going to troll with annoying advice, consider not posting. He clearly stated that decryption functioned in a reasonable time. To throw out generic canned nonsense advice like using native code was clearly not what was asked. Although you've been doing this for a while now so it's not surprising.

[dyers eve]

Originally Posted by chants

In the future if you are going to troll with annoying advice, consider not posting. He clearly stated that decryption functioned in a reasonable time. To throw out generic canned nonsense advice like using native code was clearly not what was asked. Although you've been doing this for a while now so it's not surprising.

You are not the only one who knows everything, @chants.
Whether they are right or wrong, is not for you to decide.
While you may have a better answer, if someone else also wants to post their opinions, let them do so!

@eychie It is better to avoid managed frameworks like .Net when you want to optimise for performance. It is also preferable to code the most compute-intensive parts of the encryption in C++ or better yet, in a memory-safe language like Rust.
Is there a good reason why you chose VB.Net instead of C?
I cannot comment further since I cannot access your attachment due to my low rank. I can help with the code if you provide more information, if you need.