Rating:

## [See original writeup on site](https://barelycompetent.dev/post/ctfs/2021-04-11-ritsecctf/#lorem-ipsum)

### Lorem Ipsum
> Flag is case sensitive.

We're given a `ciphertext.txt` file:

```
Incompraehensibilis Conseruator.
Redemptor optimus
Iudex omnipotens
Sapientissimus omnipotens
Redemptor fabricator
Iudex redemptor
Optimus magnus
Aeternus iudex
Auctor omnipotens.
```

As well as a photo of "Virgin Mary, mother of Jesus" which is titled **hint.jpg**.

Disregarding the hint, I tried DuckDuckGo searching for the string "Incompraehensibilis Conseruator.".

The second result was for a geocaching site, [Proz # 5: The Art of Concealing](https://www.geocaching.com/geocache/GC3NFBF_cccc-5-the-art-of-concealing).

On this website, we find this gem:

> A variant of steganography is the linguistic steganography where words of a message are replaced by synonyms based on a key-dependent rule. An example for this would be the Ave-Maria chiffre, which was developed by Johannes Trithemius in the Middle Age and where 24 names of God are translated into 24 letters. The picture on the right shows an improved variant where each letter is represented by two names of God. For example the following phrase:
>
> Omnipotens Pacificus Dominus Consolator Deus Sempiternus Imperator Maximus Fabricator Deus Gubernator Optimus Pastor Sapientissimus Conseruator Conseruator Sapientissimus Aeternus Fortissimus Illustrator Magnus
>
> stands for the _text steganography is simple_

So, we know we seem to be working with an Ave-Maria cipher. They also provide an image of how to decode the ciphertext to plaintext on that site:

![](http://img.geocaching.com/cache/acaf9a80-ca23-4bd5-a4f5-94759d5a9eb7.jpg)

 

So, we can manually decipher the plaintext, looking like so:

```
Incompraehensibilis Conseruator.
(R) (S)

Redemptor optimus
(T) (h)

Iudex omnipotens
(I) (s)

Sapientissimus omnipotens
(I) (s)

Redemptor fabricator
(T) (r)

Iudex redemptor
(I) (t)

Optimus magnus
(H) (e)

Aeternus iudex
(M) (i)

Auctor omnipotens.
(U) (s)
```

I assumed the captialized ciphertext meant capitalized plaintext, and likewise for lowercase. Submitting it succeeds.

Flag is `RS{ThIsIsTrItHeMiUs}`.

Original writeup (https://barelycompetent.dev/post/ctfs/2021-04-11-ritsecctf/#lorem-ipsum).