Cipher block chaining (CBC) is a method for encrypting large amounts of data with a block cipher that can only encrypt fixed length plaintexts. When used with an unpredictable initialization vector (IV), it is secure against chosen plaintext attacks (CPA-secure).

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Why is there an extra block when encrypting?

I am passing input data 20 bytes long and java AES-CBC returns 48 bytes instead of 32 which is what I think it should output because of padding. My key is 16 bytes long. ...
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Increasing the diffusion of the AES-CBC encryption algorithm in pycrypto for python

When encryption is done using the AES-CBC algorithm, the encryption can be thought of as chaining the cipher texts with the previous ones and an IV. However, if its on CBC mode, we give our cipher ...
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Cracking an appliance's network protocol

I'm trying to crack my thermostat's network protocol. I've captured several rounds of network traffic and here is what I've got to work with. Communicating via HTTP POST The POST data is JSON ...
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Modes of Operations Exercise

I am currently stuck at an exercise for my Cryptography Class in University which is: Alice wants to send a message $M = (M_1,M_2) =$ "Pay Bob \$100 from bank accout $12345$" to her bank (encrypted). ...
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if using cbc+hmac dealing with small size of data(less than 128bit) , will it cause any problem?

if use AES-cbc,HMAC-SHA256, and there is some txt needed to be enc, and I divide this txt into small packages with variable length, then enc them. some of these package can be less than 128bit. Is ...
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NRPAD and FPAD padding schemes (Korean Seed?)

I've got an API spec that specifies NRPAD and FPAD as possible padding schemes. I see these being used together with the Korean SEED algorithm. The SEED specification however is void of any padding ...
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CBC-MAC, possible attack that violates computational resistance

received this question in an assignment and figured the wizards of crypto.stackexchange could give me some useful and relevant input. Suppose an attacker knows three message/CBC-MAC pairs $(M_1 , ...