Cipher Block Chaining (CBC)
{"Image DocumentName": "Cipher Block Chaining (CBC)", "Image ImageDescription": "All lines transmit as many characters as a block comprises Addition mod appropriately chosen modulus Subtraction mod appropriately chosen modulus. n+2. If error on the line: Resynchronization after 2 blocks, but block borders have to be recognizable. bit error. n. n+1. memory for ciphertext block n-1. memory for ciphertext block n-1. key. key. storing cipher text \uf0e0 using it for next blocks \uf0e0 therefore cipher block chaining. first block like ECB! sum \uf0e0 usually XOR. IV: could be anything like a counter etc. -> not need to keep it secret. if all plaintextblock are the same \uf0e0 still different output \uf0e0 main motivation for construction. important property: self synchronizing! effect of bit error \uf0e0 on block is gabbled + stored! \uf0e0 next block with one bit error \uf0e0 afterwards all ok again \uf0e0 state will be re-synced after two steps! (because of forward flow) encryption. decryption. \uf0b7 \uf0b7 plaintext block n. ciphertext block n. plaintext block n. self synchronizing.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}