Tags: crypto 

Rating:

we collect all the frequences and convert the frequencies in ordrer in to characters (ascii encoding) :
```python
dictio = {}
with open("msg.txt") as fd :
data = fd.read()

letters = []
for i in data :
if i not in letters :
letters.append(i)
if i in dictio.keys() :
dictio[i] += 1
else :
dictio[i] = 1
print("".join(list(map(lambda x : chr(dictio[x]) , letters))))
```
flag :
`bcactf{ch4r4ct3r_fr3qu3ncy_15_50_c00l_55aFejnb}`