import numpy  as fw
#欧几里得算法求逆
def Euclid(a,b=26):
    x1 = 1
    x2 = 0
    x3 = a
    y1 = 0
    y2 = 1
    y3 = b

    while y3 != 0 :
        q = int(x3/y3)
        t1 = x1-q*y1
        t2 = x2-q*y2
        t3 = x3-q*y3

        x1 = y1
        x2 = y2
        x3 = y3

        y1 = t1
        y2 = t2
        y3 = t3

        if x1<0:
            x1 = x1+b
    return x1

#求模m的逆矩阵
def  want1(x):
    a=x[0,0]
    b=x[0,1]
    c=x[1,0]
    d=x[1,1]
    k=a*d-b*c
    k=Euclid(k)
    x1=[[(k*d)%26,(-k*b)%26],[(-k*c)%26,(k*a)%26]]
    return x1


#加密
def hill2encrypt(c1,A):
    c11=[0,0]
    c1111=[]
    for i in range(len(c1)):
        if c1[i]=='z':
            c1[i]='`'
    for i in range(len(c1)):
        if  i%2==0:
          c11[0]=ord(c1[i])-96
        else:
            c11[1]=ord(c1[i])-96
            strc11=str(c11[0])+';'+str(c11[1])
            c111=fw.mat(strc11)
            c111=A*c111
            x=chr((int(c111[0][0]))%26+96)
            y=chr((int(c111[1][0]))%26+96)
            if x=='`':
                x='z'
            if y=='`':
                y='z'
            c112=x+y
            c1111.append(c112)
    c1111=''.join(c1111)
    print('加密后为',c1111)


#解密
#def hill2decrypt(d1):
def hill2decrypt(d1,A1):
    d11=[0,0]
    d1111=[]
    for i in range(len(d1)):
        if d1[i]=='z':
            d1[i]='`'
    for i in range(len(d1)):
        if  i%2==0:
            d11[0]=ord(d1[i])-96
        else:
            d11[1]=ord(d1[i])-96
            strd11=str(d11[0])+';'+str(d11[1])
            d111=fw.mat(strd11)
            d111=A1*d111
            x=chr((int(d111[0][0]))%26+96)
            y=chr((int(d111[1][0]))%26+96)
            if x=='`':
                x='z'
            if y=='`':
                y='z'
            d112=x+y
            d1111.append(d112)
    d1111=''.join(d1111)
    print('解密后为',d1111)

#开始
print("请输入一段4字母的用hill2加密的明文和其密文（线性无关）")
a = input('明文为：')
b = input('密文为：')
c = input('想要加密的明文为：')
d = input('想要解密的密文为：')
'''
a='taco'
b='ucrs'
c='clintonisgoingtovisitacountryinmiddleeastt'
d='ojwpiswazuxauuiseabaucrsiplbhaammlpjjotenh'
'''
#输入已知的明文和密文
a=list(a)
for i in range(4):
    if a[i]=='z':
        a[i]=='`'
a[0]=str(ord(a[0])-96)+' '
a[1]=str(ord(a[1])-96)+' '
a[2]=str(ord(a[2])-96)+';'#abcdefghijklmnopqrstuvwxyz
a[3]=str(ord(a[3])-96)    #cfglkroxsdwjapevibmhqnutyz
a[1],a[2]=a[2],a[1]
a=''.join(a)

b=list(b)
for i in range(4):
    if b[i]=='z':
        b[i]=='`'
b[0]=str(ord(b[0])-96)+' '
b[1]=str(ord(b[1])-96)+' '
b[2]=str(ord(b[2])-96)+';'
b[3]=str(ord(b[3])-96)
b[1],b[2]=b[2],b[1]
b=''.join(b)

#a,b变为矩阵
a1 = fw.mat(a)
b1 = fw.mat(b)
'''print('a1:\n',a1)
print('b1\n',b1)
'''
A=b1*want1(a1)
A1=want1(A)
'''print(A1)'''

#对要明文和密文操作
c1=list(c)
d1=list(d)
print('A:\n',A)
print('A1:\n',A1)
hill2encrypt(c1,A)
hill2decrypt(d1,A1)