Re: Codebusters C
Posted: March 25th, 2019, 7:31 pm
Can somebody please explain this event? It just got released to division B and I don't really understand how it works.
Not sure if your rules are different, but basically you get a list of bunch of ciphers that you're expected to either decode, encode, or both. Usually the type of cipher is specified. Check the Wiki for more details and Test Exchange for example problems.WangwithaTang wrote:Can somebody please explain this event? It just got released to division B and I don't really understand how it works.
You can also practice through the question marathon if you want, although it's not entirely reliable in terms of how active it is.UTF-8 U+6211 U+662F wrote:Not sure if your rules are different, but basically you get a list of bunch of ciphers that you're expected to either decode, encode, or both. Usually the type of cipher is specified. Check the Wiki for more details and Test Exchange for example problems.WangwithaTang wrote:Can somebody please explain this event? It just got released to division B and I don't really understand how it works.
I compete in this event for Division B. The rules are pretty much the same, but we don't have to know Hill Cipher, RSA, Affine Analysis, and Affine decryption. What you do need to know is Aristocrats, Patristocrats, Baconian, Affine encryption, Atbash, Caesar Cipher, Xenocrypts, Vigenere, and Running Key Cipher (I think that's it?). You don't have notes for this event, so memorize! The test format can vary, but it always starts off with a timed question. You can get bonus points based on how fast you answer. The rest of the test is just cracking the rest of the codes. Definitely go read your rules!wec01 wrote:You can also practice through the question marathon if you want, although it's not entirely reliable in terms of how active it is.UTF-8 U+6211 U+662F wrote:Not sure if your rules are different, but basically you get a list of bunch of ciphers that you're expected to either decode, encode, or both. Usually the type of cipher is specified. Check the Wiki for more details and Test Exchange for example problems.WangwithaTang wrote:Can somebody please explain this event? It just got released to division B and I don't really understand how it works.
okay, thanks guys!starfruit wrote:I compete in this event for Division B. The rules are pretty much the same, but we don't have to know Hill Cipher, RSA, Affine Analysis, and Affine decryption. What you do need to know is Aristocrats, Patristocrats, Baconian, Affine encryption, Atbash, Caesar Cipher, Xenocrypts, Vigenere, and Running Key Cipher (I think that's it?). You don't have notes for this event, so memorize! The test format can vary, but it always starts off with a timed question. You can get bonus points based on how fast you answer. The rest of the test is just cracking the rest of the codes. Definitely go read your rules!wec01 wrote:You can also practice through the question marathon if you want, although it's not entirely reliable in terms of how active it is.UTF-8 U+6211 U+662F wrote: Not sure if your rules are different, but basically you get a list of bunch of ciphers that you're expected to either decode, encode, or both. Usually the type of cipher is specified. Check the Wiki for more details and Test Exchange for example problems.
Can you send a sample timed question you took for length? Strategies vary based on how long the timed question is.will0416 wrote:Anyone got higher level tips for the TQ? We currently average in the 1:40's but I'm assuming that we'll be a bit slower at tournaments to come (I'd say our slowest recent time has been 2:30 and we want to prevent that from happening in a high-stakes scenario).
Basically, a crib is a portion of the plaintext, so if you're given, say, the first three words already decrypted, then you would line those up with the ciphertext and subtract the plaintext letter values (be sure to use A=0) from the ciphertext letter values, which should result in the letter values of the key used to encrypt the cipher once you've gone through enough plaintext-ciphertext letter pairs. Once you've found the key, you can just copy it down over the rest of the ciphertext and solve normally.WangwithaTang wrote:Ok, can somebody explain how to do the crib method for Vigenere Ciphers?
oh, okay, thanks!dragonfruit35 wrote:Basically, a crib is a portion of the plaintext, so if you're given, say, the first three words already decrypted, then you would line those up with the ciphertext and subtract the plaintext letter values (be sure to use A=0) from the ciphertext letter values, which should result in the letter values of the key used to encrypt the cipher once you've gone through enough plaintext-ciphertext letter pairs. Once you've found the key, you can just copy it down over the rest of the ciphertext and solve normally.WangwithaTang wrote:Ok, can somebody explain how to do the crib method for Vigenere Ciphers?