Simplified-AES.sagews

attach("saes.py")
saes = SAES()

def xor(A,B):
    return bin(''.join('0' if i == j else '1' for i, j in zip(A,B)))

def L8(A):
    return A[0:8]

def R8(A):
    return A[8:16]

bin = BinaryStrings()
key = bin("1110111011110000"); key
P = bin("0000000000000001"); P

1110111011110000 0000000000000001

C=saes(P,key,algorithm="encrypt"); C

0101001000010100

C2=saes(C,key,algorithm="encrypt"); C2

0101110011101001

saes(C,key,algorithm="decrypt")

1000011100111011

#Determine Roundkeys
MS = MatrixSpace(FiniteField(16, "x"), 2, 2)
matK = MS(saes.binary_to_GF(key)).transpose() #Convert Key to Matrix
rkey0=saes.round_key(matK,0)
rkey1=saes.round_key(matK,1)
rkey2=saes.round_key(matK,2)
print "K0",saes.GF_to_binary(rkey0)
print "K1",saes.GF_to_binary(rkey1)
print "K2",saes.GF_to_binary(rkey2)

K0 0100101011110101 K1 1101110100101000 K2 1000011110101111

saes.binary_to_GF(P)

[x^3, x^2 + x + 1, x + 1, x^3 + x + 1]

#round 0
matP = MS(saes.binary_to_GF(P)).transpose()
C0=saes.add_key(matP, rkey0)
print "Add round key 0:",saes.GF_to_binary(C0)

Add round key 0: 1100110111001110

#round 1
S1=saes.nibble_sub(C0, algorithm="encrypt")
print "Substitution",saes.GF_to_binary(S1)
SR1=saes.shift_row(S1)
print "Switch Rows",saes.GF_to_binary(SR1)
MC1=saes.mix_column(SR1)
print "MixColumns",saes.GF_to_binary(MC1)
C1 = saes.add_key(MC1, rkey1)
print "Add round key 1:",saes.GF_to_binary(C1)

Substitution 1100111011001111 Switch Rows 1100111111001110 MixColumns 0101101000011011 Add round key 1: 1000011100110011

#round 2
S2=saes.nibble_sub(C1, algorithm="encrypt")
print "Substitution",saes.GF_to_binary(S2)
SR2=saes.shift_row(S2)
print "Switch Rows",saes.GF_to_binary(SR2)
C2 = saes.add_key(SR2, rkey2)
print "Add round key 2:",saes.GF_to_binary(C2)

Substitution 0110010110111011 Switch Rows 0110101110110101 Add round key 2: 1110110000011010

0010010001110000

0010010001110000

1101011100101000

P

1101011100101000

P1 = bin("1101011100101000"); P1
P2 = bin("1110001011000111"); P2
C0 = bin("0000000000000000"); C0
X1 = bin("0101000010001010"); X1

#ECB:
C1=saes(P1,key,algorithm="encrypt");C1
C2=saes(P2,key,algorithm="encrypt");C2

0010010011101100 0011101000001010

#CBC:
C1=saes(xor(P1,C0),key,algorithm="encrypt");C1
C2=saes(xor(P2,C1),key,algorithm="encrypt");C2

0010010011101100 0010010110001101

saes(C1,key,algorithm="decrypt")

1101011100101000

xor(saes(C2,key,algorithm="decrypt"),C1)

1110001011000111

P2

1110001011000111

#CBC
C1=saes(xor(P,Z),key,algorithm="encrypt");C1
C2=saes(xor(Q,C1),key,algorithm="encrypt");C2

0010010001110000 1000011101110101

#Decrypting CBC
saes(C1,key,algorithm="decrypt")

1101011100101000

xor(saes(C2,key,algorithm="decrypt"),C1)

1110001011000111

Q

1110001011000111

Z = bin("0000000000000000"); Z
P1 = bin("00110011")
P2 = bin("00110000")
P3= bin("10101101")
P4 = bin("11000000")

0000000000000000

#CFB
O1=L8(saes(X1,key,algorithm="encrypt"));O1
C1=xor(O1,P1);C1
X2=R8(X1)*C1;X2

00000000 00110011 1000101000110011

O2=L8(saes(X2,key,algorithm="encrypt"));O2

11011010

C2=xor(O2,P2);C2

11101010

X3=R8(X2)*C2;X3

0011001111101010