Questions tagged [cbc]

Cipher Block Chaining (CBC) is a block cipher mode of operation.

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How to alter text that was encrypted with AES CBC using PKCSPadding7 [migrated]

Assuming, I had a ciphertext along with its decrypted plain text result but not the IV or the Secret Key. (keep in mind that the text was encrypted with AES/CBC/PKCSPadding7). How would I go about ...
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Are ECB and CBC modes of operation generally insecure?

In some Java code that I'm reading, I stumbled over the following encryption algorithms passed to the Cipher.getInstance(...) method: AES/CBC/PKCS5Padding DESede/ECB/PKCS5Padding RSA/ECB/PKCS1Padding ...
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How does one implement chunked CBC encryption safely; is this implementation flawed?

UPDATE: Upon further research, I discovered a library that appears to meet my needs, especially with regard to the chunked aspect. Rather than "roll my own", I would be better served to use this well-...
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Decrypting AES-128-CBC leads to first block being correct, the rest corrupt

I'm currently investigating a piece of software which encrypts it's files with AES-128-CBC. From disassembly it is truly known that the algorithm used is correct (log messages plus calls to the ...
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What if the attacker tamper the IV used in the block cipher CBC mode?

I am a newbie to block cipher and when learning the CBC mode, I start to understand that an IV is being used in this mode and also will be transferred to the message receiver. So here is my question,...
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What is the impact of the reported weak IV in 7 Zip?

It has been reported that 7 Zip generates IVs in a weak manner. What is the actual impact of this? I'm asking about historical Zip files that I've sent. I've no plans to use 7 Zip going forward until ...
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Why does SSL Labs now consider CBC suites weak?

Why does SSL labs now mark CBC 256 suites as weak, although equivalent GCM and ChaCha20 are considered strong? Until a few months ago, it was unmarked in reports (neither explicitly as weak or strong),...
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Why is authentication impossible with CBC mode?

Suppose I have a protocol where fixed-length messages (1280 bytes, no padding) are encrypted with AES in CBC mode. I want to put some data in the message body to verify that the message is authentic. ...