Symmetric cryptosystems assume two communicating entities share a pre-established secret key.
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86 views
True 128bit secured password length?
assume we say 128bit keys are secure so a 16 character long password is safe, but if i even use lower case and upper case letters with numbers and special characters on my keyboard its about 80 ...
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1answer
108 views
How do I calculate the maximum plain text length allowable for a certain cipher text length?
I am encrypting and storing sensitive values in the database. I have a set max length in the database, but in order to provide useful user feedback, I'd like to know the max input I should allow for a ...
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379 views
AES GCM symmetric encryption of data at rest in c#, ciphertext much longer than plaintext
I've written encryption/decryption routines using AES GCM. Code can be found here.
I recently realized that the cipher text is longer than I believe it should be. It should add the tag and IV onto ...
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1answer
99 views
brute force attack on KDF vs KEY
if we believe 256bit keys are secure in AES against any brute force attack, is that possible we use a KDF (convert user's weak entered password in truecrypt into a fixed AES key) with too much round ...
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2answers
59 views
Prepend information about encryption implementation to the stored data
I want to preface this by saying i will not be using any of this code/information in a live project, this is only for learning/fun (so I welcome some speculation)
I was looking at how the PHP crypt() ...
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1answer
77 views
Question about use of IV in this cipher
Main cipher objective : Generate a keyed CSPRN stream, that does not expose useful information about the state of the CSPRNG, and xor this with the plaintext. To prevent an attacked who could somehow ...
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2answers
135 views
Does gpg's symmetric encryption keep information about the filename?
If I encrypt a file with gpg -c file.zip, and change the filename. Is there any way I can restore the filename as I used as a password. or the name encrypted to?
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1answer
65 views
Is symmetric key encrypted with server's public key secure
I'm trying to implement lightweight yet secure protocol for communicating two trusted parties with each other.
Consider following scheme:
Alice wants to establish secure two-sided channel with ...
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1answer
164 views
Polynomial for secure communication
Can we use a polynomial $P(x)$ to securely communicate ?
For example Alice & Bob agree on a degree of a polynomial. The value $x$ & the coeficients are generated from a seed using a hash ...
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1answer
73 views
Random decomposition of symmetric key
Considering a symmetric cipher (i.e : AES in counter mode), is it possible for any given key to be randomly decomposed into other keys without knowing the message or the ciphertext, such as :
100 = ...
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0answers
73 views
Cryptograpy library for Python [closed]
I was searching for libraries/modules for encryption of data and found a few such as M2Crypto and GNUTLS but both of them don't support CMAC which is what I wanted to use for authentication. Anyone ...
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2answers
176 views
Cryptographic Symmetric Stream Cipher
Let me know a cryptographic symmetric stream cipher system with only two functions say S() and P() and it should satisfy the following conditions:
There will be two independent computers say M1 and ...
