Description of De-Crypter

Main Raptor Cryptographic Alternative Algorithm

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Algorithm

To decrypt the obtained string sequence from the Crypter, you have to follow these steps :

• Rebuild the terms list from the given string using sep and vir Sets

• Convert crypted value to their integer index

• Devide each of value by 10 to get the smaller origianl values

• Rebuild float values from the integer couples values

• Round multiplication of float value and Mirror key value to rebuild terms

• Divide each computed values from multiplication of i_term fo the float list with the last computed term by 10000 to get origianls terms

• Round and convert to ASCII values to get the original string

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Source Code

from base_opt import *
import random as r

sep=['!','"','#','$','%','&','(',')','*','+',',','-','.','/']
vir=['A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z']

table=table()


string=input('Chaine Cryptée : ')
str_key=input('Clé : ')

Mirror_key=[]
tmp=''
ind=0
for item in str_key:
        if not item in sep :
                tmp+=item
        else:
                Mirror_key.append(int(tmp))
                tmp=''
                ind+=1

rez=[]
tmp=''
ind=0
first=Mirror_key[-1]
Mirror_key=Mirror_key[:-1]

# Rebuild the terms list from the given string using sep and vir Sets
for item in string:
        if not item in sep and not item in vir:
                tmp+=item
        else:
                # Convert crypted value to their integer index
                rez.append(table[Mirror_key[ind]].index(tmp))
                tmp=''
                ind+=1
firstt=rez[-1]
rez=rez[:-1]

# Devide each of value by 10 to get the smaller origianl values
for i in range(len(rez)):
        rez[i]/=10
Float_rez=[]

# Rebuild float values from the integer couples values
for i in range(0,len(rez)):
        if(i%2==0):
                tmp=rez[i]
        else:
                Float_rez.append(tmp+rez[i]/1000)
                tmp=0.0

# Algorithme de décryptage

# Round multiplication of float value and Mirror key value to rebuild terms
rez=[]
for i in range(len(Float_rez)):
        rez.append(round(Float_rez[i]*(Mirror_key[i]+1)))

rezz=[]
rezz.append((first*rez[0])/10000)

# Divide each computed values from multiplication of i_term fo the float list with the last computed term by 10000 to get origianls terms
for i in range(1,len(rez)):
        rezz.append((rez[i]*rezz[i-1])/10000)

final=[]
# Round and convert to ASCII values to get the original string
for i in range(len(rezz)):
        final.append(chr(round(rezz[i])))
txt=""
txt=(chr(first))
for i in range(len(final)):
        txt+=final[i]

print(txt)