It is a list of reversing challenges compiled from different CTF, whose content is the binary and solution using r2pipe, IDAPython or just reverse binary in high-level language like Python or C and some writeups!. It is a list in continuous update so enjoy and learn!.

Baby

Challenge	Output and info
9447 CTF 2015: The real flag finder	Usage: ./flagFinderRedux [arg1] Elf
Defcamp CTF Qualifications 2015: entry-language-100	Enter the password: [stdin] Elf
Hack The Box: Find The Easy Pass	Enter Password: [stdin] Exe
Hack The Box: Impossible Password	* [stdin] Elf
CCN-Cert Atenea CTF: WannaCry	Malware Exe
CCN-Cert Atenea CTF: Saint Seiya	Enter Key: [stdin] Exe
CCN-Cert Atenea CTF: Spear Phising... Can you catch me?	Malware Exe
CCN-Cert Atenea CTF: Counter	Packed Exe
CCN-Cert Atenea CTF: Crackme! if you can...	Usage: crypt0.exe [arg1] [arg2] Crackme Exe
H4CK1T CTF 2016: Crypt00perator	Enter th3 k3y: [stdin] Crackme Exe
CSAW 2016: Gametime	Exe
Hack.lu CTF 2018: Baby Reverse	Welcome to this Chall! Enter the Key to win: [stdin] Crackme Elf
INSTRUO CTF 2018: Tez Bano Tez	INSTRUO-2018 IIEST-S *** Calculating key... Crackme Elf
HoneyCON CTF 2018: Basic Conditional Decision	Usage: rev3 [arg1], Crackme Elf
X-MAS CTF 2019: Santa's crackme	[stdin], Binary: main Crackme Elf
X-MAS CTF 2019: Santa's crackme	[stdin], Binary: main Crackme Elf
Basic Algorithm Decrypt function	Usage: entropy [arg1], Binary: entropy Crackme Elf

Easy

Challenge	Output and info
r2con2018: psv	Welcome to PSV (Perfectly Secure Vault)! Enter your secret key to unlock: [stdin] Crackme Elf
r2con2018: scrabble	Usage: scrabble [arg1], Crackme Elf
r2con2018: forceme	****** As a Lockpicking master, Open the Lock! ******* Usage: forceme [arg] Crackme Elf
Navarra Lan Party CTF 2018: Key is the key	Ultimate ultra-mega hacker key checker Version: 01.1337 (Only 1 key has been saved) Usage: keyisthekey [arg1] [arg2] by KaoRz (@alextaito99) Crackme Packed Elf Anti-Debugging
Flare-On 2018: Ultimate Minesweeper	.NET Game by Nick Harbour (@nickharbour) Exe
HoneyCON CTF 2018: Brute Me	Usage: rev4 [arg1], Crackme Elf
HoneyCON CTF 2018: Ultra Secure Bank Login	Es necesario introducir los 8 PINes para realizar login en FWHIBBIT Bank PIN 1: [stdin], Crackme Elf

Medium

Challenge	Output and info
r2con2018: disqualified	Show me what you got: [stdin] by Megabeets (@megabeets_) Crackme Elf
Navarra Lan Party CTF 2018: In time	Introduce tu flag y comprueba si es la correcta [stdin] Espere unos instantes... by Gibdeon (@gibdeon) Crackme Elf
PatataCTF 2018: Angry Potato	./angry-patatas [arg] by Patatas (@HackingPatatas) Crackme Elf
InCTF 2018: Decoy	Input: [stdin] Crackme Exe Anti-Debugging
X-MAS CTF 2019: Last Christmas	Binary: LAST_XMAS Crackme Elf Packed Anti-Debugging
CTF FWHIBBIT 2020: EB SECRET	Web Access DON'T RUN AS ROOT Crackme Elf Obfuscate Anti-Debugging

Hard

Challenge	Output and info
State Machine 2018: Ret0	CLS Team 2018 Enter Password: [stdin] by @Bym24v Crackme Exe

Insane