## Can COViD break Alice’s design?

This is the second challenge from the Cryptography section of Stack-The-Flag 2020 by govtech-csg. It uses LFSR stream cipher to encrypt 500 bytes of data and...

## Can COViD steal Bob’s idea?

This is the first challenge from the Cryptography section of Stack-The-Flag 2020 by govtech-csg. The challenge wants us to break vulnerable Diffie-hellman pa...

## Gamer’s Cipher

This is the first challenge from the Cryptography section of BambooFox CTF 2021. It introduced Nimber field and do encryption using it.

## ORZ network

This is the third challenge from the Cryptography section of BambooFox CTF 2021. The challenge wants us determine if a Diffie-hellman parameter is vulnerable...

## YALA (PART 1)

This is the fourth challenge from the Mobile section of DSO-NUS CTF 2021. The challenge needs us to brute force the password for the user.

## Sekret

This is the second challenge from the Mobile section of DSO-NUS CTF 2021. The challenge needs us to find the password of a user using OSINT.

## Sighhh

This is the third challenge from the Web & Crypto section of DSO-NUS CTF 2021. The challenge uses digital certificate extension with ASN.1 encoding to st...

## Protect the Vaccine

This is the second challenge from the Web & Crypto section of DSO-NUS CTF 2021. The challenge introduced a new LSB attack on Special-Structured RSA Prime...

## Poor Men

This is the first challenge from the Web & Crypto section of DSO-NUS CTF 2021. The challenge introduced a different variation of RSA that is safe from ac...

## ctf-sg-2021

This is the third challenge from the Crypto section of CTF SG 2021. The challenge needs us to break a Stream Cipher that uses 4 LFSR.

## GRIC

This is the second challenge from the Crypto section of CTF SG 2021. The challenge needs us to find out the checksum letter when given a 10 digit number.

## Long Long Encrypt

This is the first challenge from the Crypto section of CTF SG 2021. The challenge introduced a different variation of RSA that uses $$n = p^{q}$$

## Space Noise

This is a challenge from Cryptography section of Standcon 2021. The challenge wants us to guess the encryption scheme

## Ingenuity Installer

This is a challenge from Cryptography section of Standcon 2021. The challenge wants us to forge a signature of a zip file.

## Interstellar Chat

This is a challenge from Cryptography section of Standcon 2021. The challenge uses AES_CTR to encrypt stuff

This is a challenge from Cryptography section of Standcon 2021. The challenge wants us to break the PRNG system.

This is a challenge from Cryptography section of Standcon 2021. The challenge provide you an encrypted text and a decryption oracle.

## Substitution Extreme

This is a challenge from Cryptography section of Standcon 2021. The challenge used subsitution cipher to encrypt a text.

## Space Papaya

This is a challenge from Cryptography section of Standcon 2021. The challenge used bad parameters for RSA encryption

## Swap on Curve

This is the fourth crypto challenge from ASCS 2021. It is an interesting question related to ECC.

## CBCBC

This is the second crypto challenge from ASCS 2021. It tried to use double AES CBC to protect against padding oracle attack.

## RSA stream

This is the first crypto challenge from ASCS 2021. It used Stream cipher with RSA to encrypt a message.