Sessions and encrypted cookies problem

[eluser]Olf[/eluser]
I checked the length of data that comes with responsibility.
Feature _add_cipher_noise - returns different amounts of data.
In good case: 960 bytes.
In the bad: 672

Here's the data in hex form:

Good

Input 896 bytes:

Code:

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

Output 960 bytes:

Code:

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

Bad

Input 896 bytes:

Code:

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

Output 672 bytes:

Code:

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