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From: Marcel Logen <333200007110-0201@ybtra.de>
Newsgroups: sci.crypt
Subject: Re: What are the chances of this encrytion being broken?
Date: Sat, 29 Mar 2025 00:08:17 +0100
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colin in sci.crypt:

>On 28/03/25 04:56, Marcel Logen wrote:

[...]

>>| user15@o15:/tmp$ openssl enc -aes-256-cbc -in 511bytes.txt -pass pass:1234 -pbkdf2 -nosalt | wc -c
>>| 512
>>
>>-nosalt => 512
>
>I think I have got my head around it now.
>
>Openssl adds salt by default.
>At least 1 byte of padding is always added ( up to 16 )

I agree.

>Hence with -nosalt
>511 -> 512
>512 -> 528 ( one block full of just padding )
>513 -> 528
>527 -> 528
>528 -> 544

In the case 512 (multiple of 128 bits) one can use -nopad.

Then

512 -> 512

Marcel