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Questions tagged [dictionary-attack]

A dictionary attack is a technique for defeating a cipher or authentication mechanism by trying to determine its decryption key or pass-phrase by trying hundreds or sometimes millions of likely possibilities, such as words in a dictionary.

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Performing a dictionary attack on RSA/ECB with no padding

I have the exponent $e=2^{16}+1$ and modulus $n$ (154 digit number) of an RSA public key along with the ciphertext (64 bytes) encrypted using the same key with RSA/ECB and no padding. I am required ...
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Is forward search attack is the same as dictionary attack?

Currently, I started to learn about secure passwords in password file. The password file contains the hashed values for passwords. I know that the forward search attack for a password that if an ...
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How to prove that a rainbow table is complete?

Passwords that are hashed but not salted can be cracked using the rainbow table. I went through this and this which explains the logic behind rainbow table very well. But I am missing something about ...
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Passphrases, Dictionary attacks and 'bit shift'

How much better would a passphrase be if you swapped the first letters of each word with a shift to the left: "correct battery horse staple" becomes "borrect hattery sorse ctaple" This would be ...
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Does a password that's cracked someone's account increase the chances of cracking someone else's account?

For every find in password that cracks someone's account, does that particular password have a higher probability of cracking someone else's account more than a brute force dictionary choice? How ...
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Why does the Secure Remote Protocol have resistance of dictionary attack?

Assume that Eeve who masquerades as a legitimate host and convinces Carol to make an authentication attempt. (Carol wants to handshake with Steve – a host) Thus, Eve can get values $A = g^a, M1 = H(A,...
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What are the problems of IKEv1 aggressive mode (compared to IKEv1 main mode or IKEv2)?

I would like to seek confirmation/clarification of the following statements about IKE: IKEv1 aggressive mode is supposed to be “insecure” if used with PSK. But as far as I can see, correct (or more ...
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XOR cipher with three different ciphertexts and repeated key, key length known. How do I find the plaintexts?

Let us say we have three different plaintexts (all alphabets, A-Z): $x$, $y$ and $z$, each of length $21$. Let the key, $a$, be also of length $21$. Now, what we have is $x \oplus a$, $y \oplus a$ ...
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SRP-6 vulnerabilities when N is small

I'm one of the developers of an application which uses SRP-6 as the authentication mechanism. The authentication part of the code is very old and uses N with only 256 bits (all arithmetic is done in ...
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What is the entropy per Diceware word if a random symbol is inserted into a random position in the word?

On the Diceware page is this little gem: For extra security without adding another word, insert one special character or digit chosen at random into your passphrase... Inserting a letter at random ...
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Problem with anonymously merging information from distributed sources

Some Background: There is an entity with an identifier and some information. The identifier of this entity is a string with a known scheme/pattern(Which means the total number of such possible ...
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Does impersonating an SRP server give you enough information for an off-line dictionary attack?

In a comment to an answer I wrote to another question, CodesInChaos wrote that: "Problem with SRP is that an attacker who impersonates a server learns the password hash, enabling offline search." ...
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Obtaining a key that's using ice algorithm

I have a text file that has been processed by the SNOW steganography tool that uses ICE encryption. However, I do not know the key that would enable me to decrypt and retrieve the message hidden. ...
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Zero Knowledge auth schemes with weak secret

In Zero Knowledge auth schemes the public DH factor of each peer is encrypted with a potentially weak pre-shared secret and the resulting ciphertexts are exchanged over an insecure channel. Why is no ...
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What would be the most effective way to brute force a 16 char AES key?

I have a file that is encrypted in AES using a 16 char string. The string is (a-zA-Z0-9) and .,?!. Also, it only contains words ...
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How realistic is a dictionary attack on a secure remote password protocol (SRP) verifier?

I'm deploying a secure remote password protocol implementation and I'm wondering what the consequences are when the client generated verifier gets leaked to an attacker. I've read Thomas Wu's paper ...
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How can rainbow tables be used for a dictionary attack?

I'm putting together a password policy for my company. I very much want to avoid requiring complex passwords, and would much rather require length. The maximum length I can enforce is 14 characters. ...
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Dictionary attack on pass-phrases on common algorithms?

I don't yet perfectly understand the difference between brute-force and dictionary attack since this differentiates one attacking the key and another attacking password: apparently attacking passwords ...