USE OF MODERN BLOCK CIPHERS Symmetric-key encipherment can be done using modern block ciphers. Modes of operation have been devised to encipher text of any size employing either DES or AES. 1 USE OF MODERN BLOCK CIPHERS Electronic codebook (ECB) mode Error Propagation A single bit error in transmission can create errors in several in the corresponding block. However, the error does not have any effect on the other blocks.