Reverse Engineering challenge #44.

Tags: X86 EXEC L2 WINDOWS CRYPTO .

There is an utility which encrypts/decrypts files using a password. There is an encrypted text file, the password is unknown. The encrypted file is a text in the English language.

The utility uses a relatively strong cryptosystem, nevertheless, it was implemented with a serious blunder. With the mistake present, it is possible to decrypt the file with a little effort.

Try to find the mistake and decrypt the file.

Windows x86.

The text file: files/text_encrypted.

More challenges: challenges.re; about solutions: challenges.re/#Solutions.