ALPHABET $="0123456789$ABCDEFGHIJKLMNOPQRSTUVWXYZ$\_$#$"$

message $=\text{'}$CV$4$RS$7$KDAPWZCT$4$Y#GD$56$W$34$UGY$1$C$8$D$2$HWU$3$B$0$RY$00\_1$S$694$SPJ$854$KG$6$AI$\_$D$0$UXSG$83$SDY$7$YEUW$1$S$76$GJAGUCY$8$O$59$FG$6$WZGPM$854$KDD$6$WWYKZ$803$K$56$NIZCCJ$8$WGB$\_$FWX$4$UP$4$K#VK$9$GK$2$WB$0$G$1$CZ$\_$FSO#SJN$4$SCZ$\_9$HWG$4$S$0$V#S$9$DMSHU$8$Q$0$YKWVK$6$SO#WYDR$24$Z$\_1$S$9$YWNN$280$ZKGANI$8$FG$4$O$9$U$5\_$AIYVYPU$8$QWB$2$EK$5$EYK$4$#S$55669$I$8$FG$4$KR#EGLAXGFGX$8$VWW$1$SCYSP$0$GXRG$2$O$9$A$35$CF$4$RS$7$KG$9$AI$9$FCTUSVKA$6$WU$3$B$0$G$0$QW$7169$I$9$FG$405$W$9$GSW$4$SW$07$HCG$2$O$96$DWYOGNSGW$9$DWA$4$PVY$80$XK$\_4$MCSGPZK#U$\_$GS$7$C$9$YJG$3$SGWGSUY$9$YHU$2$#VKBGWA$4$AKK$1$AG$2$OCJ$6$CYPU$1$CC$1\_$LWU$9$RTGM$5\_8$BSEI$5$MUYO$48$K$3$GNI$9$FG$4$ZS$4996$WA$4$YOGXAG$83$SP#WK$0$RSYWKA$6$WU$3$B$0$G$15$SY$5$SP#WKUKV$7$WCOLKI$2$C$0$GXRGD$56$JI$\_$YHKOZGCCJNGGUJKXC$912$SN$6$SB$00$OC$5$EFKQYGRQMO$5$Z$\_$FSC$6$WQ$0$UXZEK$\_$SO#$4$PV$4$NW$8$D$\_$F$8$YGGH$460$AK$6$FMC$\_$PG$44$VSDOLDYGNGUZZWK$\_$JAI$1$GMK$8$VWB$2$SEI$2$SUZ$8$O$3$CK$6$NI$9$FG$40$O$2\_$O$2$OIWTGX$68$Z$\_$F$6$WBZC$0$N$2\_$S$7$OJ$6$WWYKY$8$PADO$2$W$44$LQZY#$4$EGS$6$ZX$8$KX$8\_4$CHSKZGRJKWC$1$W#GQ$9$GRJK$8$U$7\_\_$LA$9$GNCX$1$C$4$#OLDY$\_$P$0$ZS$\_$WK$3$GNI$2$CTK$84$AXGAOBWLEK$8$O$3$ZOLDYGQEGX$5$EKDGNB$\_$MP$4$YTG#F$6$AX$4$K$00$RWU$1$OJA$4$SGPY$854$KH$9$A$4$GQQ$4134$E#DAAGRJKWC$91\_$LWBZC$\_424$WK$2$NA$9$EYG$1$O$392$CFWB$4$YIK$1$C$721$SKZGGV$4$YVGD$56$WXWQVOXAG$83$SIU$3$Y$0$H$25$GD$56$UISPG$4$KC$7249$PIYMQJ$844$BHSKZGNGUZZWK$67$W$0$GMEIK$4\_8$B$2$H$3$EYHU#UWDOEUAWJH$4$K#VKH$2$GYGNCX$1$C$\_7$OLDYGGPTYQW$7$HSL$3$W$8$U$\_\text{'}$

def getOrd$($x$)$:

$"""$ Returns the order of the character in the new alphabet"""

if ord$($x$)>=$ ord$("$A$")$ and ord$($x$)<=$ ord$("$Z$")$:

return ord$($x$)-$ ord$("$A$")+10$

elif ord$($x$)<=$ ord$("9")$ and ord$($x$)>=$ ord$("0")$:

return int$($x$)$

elif x $=="\_"$:

return len$($ALPHABET$)-1$

else:

return $-1$

def addChar$($marginals$,$ index, x$)$:

$"""$

Appends the character in the index's dictionary

$"""$

if x in marginals$[$index$]$:

marginals$[$index$][$x$]+=1$

else:

marginals$[$index$][$x$]=1$

def marginalFreq$($l$,$ message$)$:

$"""$

Returns the marginal probability distributions

$"""$

marginals $=[\{\}$ for $\_$ in range$($l$)]$

for index, x in enumerate$($message$)$:

addChar$($marginals$,$ index$\%$l$,$ x$)$

return marginals

def distance$($marginal$)$:

$"""$ Distance of a probability distribution"""

size $=0$

dist $=0$

for val in marginal.values$()$:

size $+=$ val

dist $+=$ val$**2$

return dist$/($size$**2)$

def totalDistance$($marginals$)$:

$"""$ Computes the global distance by summing

the distances of marginal distributions $"""$

globDist $=0$

for marginal in marginals:

globDist $+=$ distance$($marginal$)$

return globDist

MAX$\_$LENGTH $=25$

def indexMax$($lista$)$:

'Returns the index of the maximum'

indexMax $=0$

maximum $=-$float$("$inf$")$

if not lista:

return None

for index, val in enumerate$($lista$)$:

if val $>$ maximum:

indexMax $=$ index

maximum $=$ val

return indexMax

def guessLength$($message$)$:

dist $=[]$

marginals $=[]$

for length in range$(1,$ MAX$\_$LENGTH $+1)$:

marg $=$ marginalFreq$($length$,$ message$)$

marginals.append$($marg$)$

dist.append$($totalDistance$($marg$))$

period $=$ indexMax$($dist$)$

return indexMax$($dist$),$ marginals$[$period$]$

def computeOffset$($marginal$)$:

$"""$ Computes the offset of a marginal distribution"""

sortedM $=$ sorted$($marginal$.$items$(),$ key$=$ lambda x: $-$x$[1])$

return getOrd$($sortedM$[0][0])-$ len$($ALPHABET$)+1$

def computeOffsets$($marginals$)$:

$"""$ Computes the offsets for the different marginals"""

offsets $=[]$

for marginal in marginals:

offsets.append$($computeOffset$($marginal$))$

return offsets

def vigenereDecrpt$($message$)$:

$"""$ Decrypts the message by:

Identifying the period and applying

ceasar decryption for each subset"""

# We need the period and the corresponding marginals

period, marginals $=$ guessLength$($message$)$

print$($period$)$

offsets $=$ computeOffsets$($marginals$)$

decrypted $=\text{'}\text{'}$

for index, x in enumerate$($message$)$:

decrypted $+=$ ALPHABET$[($getOrd$($x$)-$ offsets$[$index$\%($period$+1)])\%$len$($ALPHABET$)]$

return decrypted

fp $=$ open$("$plainText$.$txt$","$w$")$

fp$.$write$($vigenereDecrpt$($message$))$

$-$ i am trying to decrypt a vigenere cipher. what am i doing wrong, because i am supposed to get an english plaintext. I haven't provided the entire ciphertext due to character limitation$,$ but the alphabet used are:

$0123456789$ABCDEFGHIJKLMNOPQRSTUVWXYZ$\_$#

where an underscore encodes a space and a hash character encodes a newline. Please fix the error and also provide the decoded plaintext, which should be english $($not gibbrish$)$