January 22, 2002
Practical Aspects of Modern Cryptography
16
Problems with ECB
nPatterns in plaintext preserved in ciphertext
n
n
n
n
nNo basic integrity protection.  Must add or:
nCipher block substitution and rearrangement attacks
nFabrication of information
n
Block
Cipher
Block
Cipher
Block
Cipher
Block
Cipher
X0
X1
X2
X3 = X0
C0
C1
C2
C3 = C0