ME SER Q4. (16 points). Explain the difference between CFB and OFB modes of block cipher operation. What mode is more reliable? Why? Hints: 2 IV Cu Oy NE 53 TE 64 64 K Encrypt K Encrypt KE Encrypt K Encrypt Encrypt 464 SE SE ward ward P's PM PM CM C a) Encryptica (a) Encryption Cu W H- IV Deep 64 64 64 Encrypt 64 Encrypt 64 her Decrypt 164 od Se ward SE card C CM P b) Decryption Figure 3.13 s-bit Cipher Feedback (CFB) Mode Pw P2 (b) lecryption Figure 3.14 s-bit Output Feedback (OFB) Mode ME SER Q4. (16 points). Explain the difference between CFB and OFB modes of block cipher operation. What mode is more reliable? Why? Hints: 2 IV Cu Oy NE 53 TE 64 64 K Encrypt K Encrypt KE Encrypt K Encrypt Encrypt 464 SE SE ward ward P's PM PM CM C a) Encryptica (a) Encryption Cu W H- IV Deep 64 64 64 Encrypt 64 Encrypt 64 her Decrypt 164 od Se ward SE card C CM P b) Decryption Figure 3.13 s-bit Cipher Feedback (CFB) Mode Pw P2 (b) lecryption Figure 3.14 s-bit Output Feedback (OFB) Mode