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I was wondering what the main reason was for symmetric keys not being used in this context?
With a symmetric key, anyone who could check the signature could also forge a signature. For most of the use cases of digital signatures, we want untrusted parties to be able to verify the signature. That requires that the key you use to check that a signature is correct be insufficient to generate a valid signature, and that requires asymmetric cryptography by definition.
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So yeah, different modulus(n), same exponent(e), different encrypted messages(C). Can I do anything with that to find the original messages(M) ? Thank you !
Sure. You can factor the modulus, altho for real world RSA keys, that's not gonna be very practical.
More seriously, 99% of all RSA keys use 65537 as the exponent. If a common public exponent were a weakness 99% of all RSA applications would be vulnerable.
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I have an encrypted code and decrypted code how to know the algorithm?
encrypted code of "A" is "bc1M4j2I4u6VaLpUbAB8Y9kTHBs="
encrypted code of "B" is "rk8oHfWl0P88rWNx921cKbbZU+w="
encrypted code of "C" is "MglsLg7/M9hE7m1nVAes4YKJNX0="
I am making an application which must use that algorithm I have only encrypter software that creates the code but I don't know the algorithm.
How do I know the algorithm?
It's a SHA1 base64 hash algorithm
See this Ruby code
require 'digest/sha1'
puts Digest::SHA1.base64digest 'A'
# bc1M4j2I4u6VaLpUbAB8Y9kTHBs=
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I got this question in a local hacking event, but I couldn't solve it.
Problem Statement ----
Continuing their snooping habit, NSA kept bugging Alice's communication. Resorting to the age old RSA encryption, Alice used 128-bit RSA encryption to exchange messages. Alice shares her public key as
$0xffffffa95256a837568a41c265f4fe27110814aae19f144762d5cc0bcb931807$
and her public key exponent $\phi(n)$ as $0x11$ with Warden.
However, NSA, with its enormous resource, cracked this 128 bit encryption super easily. Seeing your work on the previous ciphers, NSA decided to offer you a job in their Cryptography group. As a final test, NSA shared this public key which they intercepted from Alice and Warden's conversation. They also gave away the private key that they computed from their message exchange.
$Public$ $Key -
(0xffffffa95256a837568a41c265f4fe27110814aae19f144762d5cc0bcb931807,
0x11)$
$Private$ $Key -
(0xffffffa95256a837568a41c265f4fe27110814aae19f144762d5cc0bcb931807,$
$0xc3c3c3817b3335577e69b9d0e48e2bc1fdf71f1f4f73a38a7d628d39739bbaf1)$
What are the values of $p$ and $q$? (the prime numbers used in key generation)
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What is the key size of the SHA512 hashing algorithm? I know that the final message digest is 512 bits. I would like to know what key size it uses. Thank you very much :)
Hash functions does not use key. It just map any input to one of 2^512 possible values.
What key? There is no key. It's a hashing algorithm, not an encryption algorithm.
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I'm trying to do Encryption using software and decryption by Hardware(AES-CTR mode algorithm).But facing some issue.software I'm using openssl logic. I tried encryption by sw and Hw with same input but output is differnt :(
Encryption with hardware and software has different output.I guess that is ok. In fact that is how it should be. Normally due to random salting you get different output.
When you do decryption,, decryption should work if both hard ware and software uses same salting mechanism