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Jun
23
reviewed Close What is the danger if a non-prime is chosen for RSA?
Jun
23
reviewed Leave Open An electronic voting system
Jun
23
awarded  Caucus
Jun
23
awarded  Constituent
Jun
23
reviewed Leave Open Is it possible to break enigma code with a todays laptop
Jun
23
reviewed Leave Open An example of Knapsack Cryptosystem cracks/attacks?
Jun
3
comment Approach towards anonymous e-voting
@Alok, visual cryptography is not a very good solution for two reasons. One is the complexity - how do I know that lining up two bits of paper proves anything? To counter it, consider that XOR has no inherent security, so I can produce a matrix of dots that displays "JOHNSON" when combined with mask A, but displays "SMITH" when combined with mask B. (Consider the cheating section of that same article.) The other problem goes back to election secrecy, and that you must not be able to leave the polling place with evidence of how you voted (or else you could sell your vote.)
Apr
27
reviewed Approve How does asymmetric encryption work?
Apr
27
reviewed No Action Needed Does SRP reduce to DH key exchange when shared password is not secret?
Apr
27
reviewed No Action Needed Question about decryption
Apr
27
reviewed Close How to decrypt a '.enc' file that has been encrypted with RSA using a public key?
Mar
25
comment Authentication using a one-time pad
Have you modeled the value this system is protecting? $2^{32}$ sounds like it would be very simple to brute force attack it. All an attacker needs to do is forge a key offset of 0 for each message, and he has the winning hand. I like @poncho's suggestion of using a minimal-memory strong cypher as both the encryption and hash mechanisms, which gets further away from the roll-your-own nature of the OTP suggestion.
Mar
24
comment Authentication using a one-time pad
Not hare-brained, but you need enough bits in each of message to defend against corrupted or tampered messages, which takes a lot more than 4 bits. You also need to consider how these machines will securely re-sync if a message is lost. Restarting a one-time pad would make it be more than one-time!
Mar
24
comment credit card number encryption using aes-ctr mode
it's been a few years since I've seen them, but they were issued by American banks. I was,also basing my statement on your wording choice of "characters", not digits. 16 characters is 128 bits (ASCII), but you can obviously encode many more digits if you are willing to encode it as a big integer or BCD value. That conversion also risks loss of fidelity in the case where an issuer encodes any other value, such as a driver's license or proprietary gift card.
Mar
24
comment credit card number encryption using aes-ctr mode
Credit card account numbers are 16 digits today only by convention. The ISO standard (7314?) permits card numbers up to 22 digits in length. I've seen some debit card account numbers that are already up to 19 digits in length. I wouldn't recommend coupling the encryption mechanism to an arbitrary attribute controlled by 12,000 random bankers.
Mar
19
reviewed Leave Open AES encryption takes more time to decrypt than encrypt
Mar
19
answered Deciphering text encrypted with a changing cipher
Mar
13
reviewed Approve diffusion tag wiki excerpt
Mar
12
reviewed Approve what is the current actual budget - as of 2015 - needed to build a DES breaker machine?
Mar
11
reviewed Close Fault encryption attack on RSA