Advent of Cyber Day 12 Elfcryption

TryHackMe | Advent of Cyber

You think the Christmas Monster is intercepting and reading your messages! Elf Alice has sent you an encrypted message. Its your job to go and decrypt it!

Read the supporting materials here.

#1 What is the md5 hashsum of the encrypted note1 file?

1kali@kali:~/Downloads$ md5sum note1.txt.gpg
2"24cf615e2a4f42718f2ff36b35614f8f"  note1.txt.gpg

#2 Where was elf Bob told to meet Alice?

1gpg key is 25daysofchristmas # Hint provided by tryhackme

1kali@kali:~/Downloads$ gpg -d note1.txt.gpg
2gpg: AES encrypted data
3gpg: encrypted with 1 passphrase
4I will meet you outside "Santa's Grotto" at 5pm!

#3 Decrypt note2 and obtain the flag!

Now, if we use our private key, we can decrypt the file and get the original message:

1openssl rsautl -decrypt -inkey private.key -in encrypted.txt -out plaintext.txt

1kali@kali:~/Downloads$ openssl rsautl -decrypt -inkey private.key -in note2_encrypted.txt -out note2.txt
2Enter pass phrase for private.key: hello # private password is hello (**Hint provided by tryhackme)**

1kali@kali:~/Downloads$ cat note2.txt
2"THM{ed9ccb6802c5d0f905ea747a310bba23}"

Advent of Cyber Day 12 Elfcryption

#1 What is the md5 hashsum of the encrypted note1 file?

#2 Where was elf Bob told to meet Alice?

#3 Decrypt note2 and obtain the flag!

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