TheGiant Cipher – Possible Road to Community Solution (AES Encryption)

Hi all, I’m sharing this in the hopes that someone more experienced with ciphers/cryptography can attempt and hopefully solve.

Step 1 – Character Length

The character length of the cipher text is 192 characters long:

kCmlgFi6GUJNgkNI1Q41fbfyLoCFTCvIqkZiI0KIAXAzP1U1uy1BE4UfPBfpKmmLObjYnQNRBaPtKiVWzc5A4v0w3xle8FOhAGJZ7g4in0wndJxMOvO3dc1M82at2T6935roTqyWDgtGD/hwwRF3oHqFM5Vcw1JtINbsgWRm4o4/quEDkZ7x1B275bX3/Fo1

Due to the way base64 works, the cipher text above converts from base64 into an output of 144 characters long (albeit gibberish) and converts to base64 into an output of 256 characters long, namely:

a0NtbGdGaTZHVUpOZ2tOSTFRNDFmYmZ5TG9DRlRDdklxa1ppSTBLSUFYQXpQMVUxdXkxQkU0VWZQQmZwS21tTE9ialluUU5SQmFQdEtpVld6YzVBNHYwdzN4bGU4Rk9oQUdKWjdnNGluMHduZEp4TU92TzNkYzFNODJhdDJUNjkzNXJvVHF5V0RndEdEL2h3d1JGM29IcUZNNVZjdzFKdElOYnNnV1JtNG80L3F1RURrWjd4MUIyNzViWDMvRm8x

Step 2 – Druon Antigoon

The Black Ops 3 Data Vault contains interesting information which references The Giant and Druon Antigoon, see: https://callofduty.fandom.com/wiki/Druon

Druon Antigoon is a mythical Giant from Belgian folklore.

The Data Vault piece is by a user called ElGiganteX4 (“TheGiant” x 4 in Spanish).

Step 3 – The Belgian Connection

Two big names in Belgian cryptography are Vincent Rijmen and Joan Daemen, who created the Rijndael block cipher, now commonly known as its variant: the Advanced Encryption Standard (AES), see https://en.m.wikipedia.org/wiki/Advanced_Encryption_Standard

Step 4 – AES Encryption

AES is a variant of Rijndael, with a fixed block size of 128 bits and a key size of 128, 192, or 256 bits.

In simpler terms, this means that the cipher text must have a character length which is divisible by 16 and the corresponding key must have a character length of 16, 24 or 32.

The three types of AES encryption are called AES-128, AES-192 and AES-256.

Step 5 – Possible Solution

To solve this cipher, we need to know the CIPHER and the KEY.

CIPHER: If we collate all of the above information, our cipher text is compatible with an AES-192 decryption (English cipher text = 192 characters) or an AES-256 decryption (base64 cipher text = 256 characters).

KEY: For AES-192, a 24 character key is required and for AES-256, a 32 character key is required.

Linking back to the Data Vault post, a 32 character key is ElGiganteX4, namely: “TheGiantTheGiantTheGiantTheGiant”. However, a different key and/or configurations of the AES cipher may be required.

This is the point where I need someone with more cipher solving experience than me to step in. I believe a solution could be found if we attempt the decryption using AES configurations and various zombie relevant keyword phrases.

Here is a tool to use for AES decryption:
https://www.devglan.com/online-tools/aes-encryption-decryption

Good luck!