2022 Google CTF writeup
| Name | Category | Points | Solves |
|---|---|---|---|
| Cycling | CRYPTO | 201 / 500 | 50 |
It is well known that any RSA encryption can be undone by just encrypting the ciphertext over and over again.
If the RSA modulus has been chosen badly then the number of encryptions necessary to undo an encryption is small.
However, if the modulus is well chosen then a cycle attack can take much longer. This property can be used for a timed release of a message.
We have confirmed that it takes a whopping 2^1025-3 encryptions to decrypt the flag.
Pack out your quantum computer and perform 2^1025-3 encryptions to solve this challenge. Good luck doing this in 48h.
See attachments.
See solutions.
| Name | Category | Points | Solves |
|---|---|---|---|
| Electric Mayhem CLS | CRYPTO | 164 / 500 | 70 |
The server presents power traces of a secret firmware crypto operation. The goal is to recover the secret key.
Note, the flag is ‘CTF{XXX}’ where XXX is your recovered key.
https://electric-mayhem-cls-web.2022.ctfcompetition.com/
See attachments.
See solutions.
| Name | Category | Points | Solves |
|---|---|---|---|
| Electric Mayhem PQC | CRYPTO | 453 / 500 | 3 |
The server presents power traces of a secret firmware crypto operation. The goal is to recover the secret key.
https://electric-mayhem-pqc-web.2022.ctfcompetition.com
See attachments.
See solutions.
| Name | Category | Points | Solves |
|---|---|---|---|
| Maybe Someday | CRYPTO | 240 / 500 | 35 |
Leave me your ciphertexts. I will talk to you later.
maybe-someday.2022.ctfcompetition.com 1337
See attachments.
See solutions.
| Name | Category | Points | Solves |
|---|---|---|---|
| Enigma | CRYPTO | 373 / 500 | 9 |
Cryptanalysis has advanced a long way.
Can you break Enigma without a known plaintext?
The flag is written in all caps, with spaces and punctuation between words. It does not contain quotes.
See attachments.
See solutions.
| Name | Category | Points | Solves |
|---|---|---|---|
| Custom Protocol | CRYPTO | 420 / 500 | 5 |
I like to implement crypto myself. Please, take a look at my new implementation. It looks amazing, right?
custom-protocol.2022.ctfcompetition.com 1337
See attachments.
See solutions.
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