cryptopals | Hacking cryptography in Ruby , using Cryptopals techniques | Cryptography library
kandi X-RAY | cryptopals Summary
kandi X-RAY | cryptopals Summary
This project demonstrates attacks on state-of-the-art Cryptography implementations, including AES, RSA, SHA-1, random number generators and much more...
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Top functions reviewed by kandi - BETA
- Copies the number of random numbers .
- Equivalent to two integers
- This method is used by calculating the bounds of a point .
- strip padding
- Delegate state to state
- Verifies the signature of the blob .
- Add text to the given text .
- Returns the public key for a public key
- divide two units
cryptopals Key Features
cryptopals Examples and Code Snippets
Community Discussions
Trending Discussions on cryptopals
QUESTION
I'm actually trying to solve cryptopals set 5 challenge 39. I'm trying to implement RSA for some larger primes p and q, e = 3. I've been puzzled over this for hours.
To generate primes, I'm hitting an API to get each prime. I keep generating p until gcd(p - 1, e) == 1, and then repeat for q until gcd(q - 1, e) == 1. I've tested for gcd((p - 1) * (q - 1), e) == 1, too. For example, I end up with p == 16226322033026808497, and q == 14712923008023747557.
I then do the simple RSA math to calculate the other terms, encrypt message 42 (no padding), decrypt that cipher, and compare the resulting plain to the original message. I've generated many, many ps and qs, and it never matches.
Can someone explain why this doesn't work, and help me generate some good parameters, please?
Python:
...ANSWER
Answered 2022-Jan-05 at 23:50The API that I used to generate primes was in fact giving composites, which prevents meaningful decryption. Generating with a more reliable source, I find p == 18015945217661527751, q == 11788823512629961979, for example, which are actually prime. And I can now successfully decrypt back to the original message.
I've found that https://asecuritysite.com/encryption/random3 gives some reasonable primes.
QUESTION
I'm trying to decode this AES string: https://cryptopals.com/static/challenge-data/7.txt (from here)
The page simply says it's been AES encrypted in ECB mode using the key YELLOW SUBMARINE.
The Crypto-JS library should be able to decode this. The docs show a simple method, and I'm using it like so:
...ANSWER
Answered 2021-Oct-21 at 17:10The key must be passed to decrypt() as WordArray. This can be achieved with the Utf8 encoder.
The ciphertext can be passed directly as Base64 encoded string and is implicitly converted to a CipherParams object by CryptoJS.
This allows the ciphertext to be decrypted:
QUESTION
Intro
Hi, I'm doing some fun cryptoanalysis exercises from cryptopals, and I have now encountered an 'issue', that also has happened earlier, and I really don't understand.
currently, I have a ciphertext that I read from a file in the following way:
...ANSWER
Answered 2021-Aug-26 at 14:18Ah, I remember this problem in cryptopals, I was facepalming when I understood how this trick works.
As MisterMiyagi said it, bytes is not a sequence of "bytes", but a sequence of ints.
If you index into an str, you get another str:
QUESTION
im trying to implement a repeating key xor encryption scheme in python.
I have this implementation:
...ANSWER
Answered 2021-Jul-06 at 19:01As I mentioned in a comment, bytes(n) doesn't convert n to a byte, it creates a bytes object with n zeros. I'm sure the xor is working fine. Instead of:
QUESTION
I've followed the following site instructions in order to implement base64 encoding.
Here's my code:
...ANSWER
Answered 2021-Feb-25 at 03:32According to the site, the task is to convert the hex to base64.
Your encoding, seems to be working correctly as the library base64 outputs the same as your result when running it directly over the hex value
QUESTION
This is a part of cryptopals challenges (cryptopals.org)
Following code performs the "encrypt" operation on the ciphertext obtained from the previous round:
...ANSWER
Answered 2020-Aug-31 at 07:25Shouldn't it be in your code assert testbytes == plaintext to test your hypothesis?
Anyway. An encryption consists of two parts, the algorithm (here AES) and the mode of operation (here ECB). The algorithm itself can only encrypt a single block. The mode of operation extends this to plaintexts of any length. So that your assumption is correct, the individual processing steps and their order for decryption and encryption must be identical for both parts, algorithm and mode of operation.
Concerning the ECB mode your assumption is true, because each block is processed independently from the other (which also makes this mode insecure). However, for AES your assumption is not true, since decryption is essentially done in the reverse order to encryption, for details see here.
The easiest way to check the latter is to encrypt only one block without padding. Since the ECB mode does not use an IV, the encryption is reduced to the AES primitive itself. Padding does not have to be disabled, because PyCryptodome does not implicitly pad (in contrast to many other libraries). This case just corresponds to your code (although you have to check the equality between testbytes and plaintext). The result verifies that a double encryption using AES does not result in the original plaintext.
QUESTION
Trying to understand why taking the index of a bytes object returns an int that you can't decode, but a slice returns a bytes object that you can. This seems un-intuitive. When you do the same operation with a string, taking an index at the string position still returns a string.
Working on the Cryptopals challenges, I'm trying to iterate over a byte array to do frequency analysis of an XORed string to count the occurrence of the number of plain text letters. I thought I could do the following, but I'm getting 'int' object has not attribute 'decode' error. From reading the Python docs, that makes sense, a byte array is a mutable sequence of integers, but when testing in the interpreter I was expecting different behavior.
...ANSWER
Answered 2020-May-10 at 00:31As you've found out the bytes iterator generates integers not characters. You need to use chr to convert the int value to an str value.
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On a UNIX-like operating system, using your system’s package manager is easiest. However, the packaged Ruby version may not be the newest one. There is also an installer for Windows. Managers help you to switch between multiple Ruby versions on your system. Installers can be used to install a specific or multiple Ruby versions. Please refer ruby-lang.org for more information.
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