SAS Project 2026 - Program

Building

Required dependencies:

• riscv64-unknown-elf toolchain
  • riscv64-unknown-elf-gcc
• gcc
• Python 3
• 7z (7-zip CLI)

make

Getting the flag

Compiling with make will print the correct flag to stderr, e.g.:

[Codegen] Generated Flag: ctf{3P1WBAldo2PxYZtJIoadV_NnL1nueJAbVDtMiJhY0vQ}

Configuration

Some challenge parameters can be set with environment variables. The provided .env.example file contains a sample configuration.

• FLAG_LEN: Number, the length of the flag
• FLAG_FORMAT: String, containing the constant FLAG_GOES_HERE to be replaced by the flag
• FLAG_SEED: String, the seed used to generate the flag, or false if it should be random
• ENCRYPTOR_VENDOR_ID: String, overwrite CPU vendor id. Will use system information if unset
• ENCRYPTOR_MODEL_NAME: String, overwrite CPU model name. Will use system information if unset
• ENCRYPTOR_OS_VERSION: String, overwrite OS version. Will use system information if unset
• ENCRYPTOR_MEM_TOTAL: String, overwrite total memory (in kB). Will use system information if unset

Running the challenge

• The built binary is at build/main[.exe]
• The binary together with the encrypted license file is packaged in build/challenge.zip