def dec():
n_USER=e2.get() # GET THE USER INPUT n VALUE
if n_USER == "Enter n":
return
if n_USER == " Decryption cancelled " :
v.set("Enter n")
return
n_USR=int(n_USER)
if n_USR == 0:
e2.delete(0,END)
v.set("Enter n")
return
# RETURNS THE PATH OF THE INTERMEDIATE # TO READ THE ENCRYPTED DATA
path_im=askopenfilename(title="Path of the Encrypted File",filetypes=[("Encrypted file","*.smt"),("pythonfiles","*.py")])
#this function is imported from tkFileDialog
#you can specify the filetypes of your choice
#there is an other function called LoadFileDialog which also
# CHECKS IF DECRYPTION IS CANCELLED
if path_im == () :
v.set(" Decryption cancelled ")
return
fim=open(path_im,'r')
fim.seek(0)
# check the file if decryption possible
# genuine intermediary file
# encrypted using the same program
binLen = 16
sf_cd = 1010101010101010
bin=int(fim.read(binLen))
if bin != sf_cd :
print "\nnot safe\n"
return
else :
print "\nsafe\n"
# RETREIVE INDEX TO FIND e
# ( PUBLIC KEY )
bin=int(fim.read(binLen))
index = packages.b2a(bin)
print "index is retrieved....."#,index
# RETREIVE PHI VALUE
bin=int(fim.read(binLen))
PHI = packages.b2a(bin)
print "PHI is retrieved......"#,PHI
# RETREIVE e ( PUBLIC KEY )
fim.seek(binLen*index)
bin=int(fim.read(binLen))
e = packages.b2a(bin)
print "e is retrieved........"#,e
# CALCULATE d ( PRIVATE KEY )
d=packages.get_d(e,PHI)
print "d is evaluated........"#,d
fim.seek(binLen*24) # REACH THE n VALUE
bin=int(fim.read(binLen))
n = packages.b2a(bin)
# RECEIVE THE USER INPUT n VALUE
# CHECKS AUTHORISATION
if n_USR == n :
# RETURNS THE PATH OF THE OUTPUT FILE
# TO GET THE DECRYPTED ACTUAL OUTPUT
path_op=asksaveasfilename(title="Path of the decrypted File",filetypes=[("Text","*"),("Images","*.jpg"),("BitMapImage","*.bmp"),("pythonfiles","*.py")])
#this function is imported from tkFileDialog
#you can specify the filetypes of your choice
#there is an other function called LoadFileDialog which also
fop=open(path_op,'a')
fop.seek(0)
eoff = 1111111111111111
bin=int(fim.read(binLen))
while bin != eoff :
C = packages.b2a(bin)
M = packages.de_en(C,d,n)
txt=chr(M)
fop.write(txt)
bin = int(fim.read(binLen))
fim.close()
fop.close()
e2.delete(0,END)
v.set("0")
else :
print "Wrong n entered"
e2.delete(0,END)
v.set("0")
fim.seek(0)
binLen = 16
sf_cd = 1010101010101010
# check the file if decryption possible
# genuine intermediary file
# encrypted using the same program
bin = int(fim.read(binLen))
if bin != sf_cd:
print "\nnot safe\n"
else:
print "\nsafe\n"
bin = int(fim.read(binLen))
index = packages.b2a(bin)
print "index is retrieved....." # ,index
bin = int(fim.read(binLen))
PHI = packages.b2a(bin)
print "PHI is retrieved......" # ,PHI
fim.seek(binLen * index)
bin = int(fim.read(binLen))
e = packages.b2a(bin)
print "e is retrieved........" # ,e
d = packages.get_d(e, PHI)
