Cryptanalysis is the part of cryptology dedicated to the mathematical analysis of the weaknesses of cryptographic algorithms, the goal being to defeat some of the security properties that the algorithm should fulfill, e.g. decrypting data which has been symmetrically encrypted with substantially ...

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What keeps the private key safe if an attacker has both clear and encrypted copies of a message and the public key?

Let's say someone obtained a message in both clear text and in its encrypted copy with asymmetric cryptography, like RSA-2048. He also has the public keys. Is the private key still undiscoverable? ...
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Cryptanalysis of encrypted data at rest

Imagine I have a file encrypted using AES CBC mode with a key and a random IV. The attacker access to the encrypted text and the IV used but not the key. In this scenario there is no vulnerability ...
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242 views

Can I combine two of SHA-3 candidates cryptography hash functions and obtain more secure Algorithm? [duplicate]

Possible Duplicate: Are different hash algorithms ever used together? For example, Is possible to combine (Concatenate or Chain or XOR) Skein SHA-3 candidate with Grostl SHA-3 candidate to ...
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Knowing Input&Output, How to determine encode method and the passkey that was used in encoding?

I've looked on this site and on SE. but I couldn't get a handle on this. Is there a way to find what type of encoding (and/or encode key) is being used? For example, I am testing a web ...
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Encryption app stroring the password

The encryption app that we are using seems to generate the same output for the same input. That is bad right? I'm not smart enough to understand the scheme being used though. The header of each ...
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Does Known plaintext attacks lead to exposure of the key?

The back-story is long and boring so I will get down to the meat of the argument. I say that if a professional code breaker has a bunch of data, the encoded version of said data and the encoding ...
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912 views

Tool for generating MD4 collisions

There are a lot of research papers available online that discuss vulnerabilities of MD4 algorithm, but I couldn't find any implementation of these. Uptill now I have used tools like John the Ripper ...
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142 views

The basics of cryptanalysis [closed]

There are a lot of books on encryption. Is there a must read intro, something like Smashing the Stack for Fun and for profit, that more or less everyone reads?
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268 views

any small idea to decode this algortihm from php script [closed]

So I think the algorithm is based on the php function ENCODING_decode defined in includes/encoding.php (which i don't have) . The encoded result $xId_campaign_encoded from the php script has ...
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433 views

Best protection against a “chosen-ciphertext” attack?

What is the best protection against a "chosen-ciphertext" attack when transmitting (=streaming) secured (=crypted) data via networks using the TCP protocol?
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Frequency Analysis [closed]

I have started looking into Crytography, and the obvious starting point is frequency analysis. As a task for myself I thought it would be good to compile a script which could be used for perform the ...
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Google's usage of RC4

I was reading about Google's usage of RC4 and an answer on stackexchange website stated the following: I know Google uses RC4 for most of its services, and this is the reason one shouldn't keep ...
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cold boot attacks

To quote the wikipedia article on Cold Boot Attacks: In cryptography, a cold boot attack (or to a lesser extent, a platform reset attack) is a type of side channel attack in which an attacker with ...
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How key_derivation and key_verification functions are implemented of a 7-zip archive's encryption mechanism?

I am curious about how password recovery works for password protected files. And I want to know the exact flow of the 7-zip encryption mechanism :) !! 7-zip uses the AES-256 encryption algorithm in ...
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120 views

Timing analysis attack and cryptosystem

Why is a “Timing Analysis Attack” a problem for a cryptosystem? I've been trying to learn security, and have a question about timing analysis attack.
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1answer
133 views

Who can view my https browsing habbits? [closed]

I was wondering about HTTPS security and how easily is compromised. I have already read the similar threads in here, but I have some more questions: Let's say I am searching something at Google. ...
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126 views

Crack Unknown Encryption [closed]

I was challenged by a friend to decrypt a piece of text that was somehow encrypted. The encrypted text is the following: ...
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2answers
298 views

how to identify plain text from cipher [closed]

I am trying to find what encryption algorithm has been used in this code original text: 11011698 encrypted text/cipher: uIC4hZFECIAYMi%20FWxamjQ== original text:11008569 encrypted text/cipher: ...
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2answers
96 views

Facing hard encryption [closed]

I have a little problem with encryption. I have this cipher text "AA969CF9657F77C597C8EAFF1594D59374E4977F" and i know that correspond to "http://jogos.meo.pt/". I have another samples, but i can´t ...
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Would this kind of encryption be good at anything?

I have put much thought into this very simple algorithm and I have no clue if it was thought before... But I think it should have. I also know nothing about other encryption algorithms so I can't tell ...