Could some one please help me figure this question out? I will rate! Thank you!!
2. Encryption using different ciphers and modes The algorithm seems to follow the pattern: (Algorithm name)-(key size)-(encryption mode) Noted: If the key size is omitted or excluded then it means there is only one key-size for that algorithm Algorithm name: Sometimes there is number included in the algorithm name whose usage is to distinguish the version of the algorithm; for instance, RC2 and RC4. Key size: key size is in bit. The longer the key the stronger your encryption is, but the slower operation it takes. Encryption mode: there are five main encryption mode that widely use in block cipher mode operation, Electronic Codebook (ECB), Cipher Block Chaining (CBC), Cipher Feedback (CFB), Output Feedback (OFB), and Counter (CTR) There are several encryption algorithm in OpenSSL as shown in image below. $ openssl enc --help -aes-128-cbc -aes-128-cfb8 -aes-192-cbc -aes-192-cfb8 -aes-256-cbc -aes-256-cfb8 -aes128 -bf -bf-ecb -cast -cast5-cfb -des -des-cfb1 -des-ede -des-ede-ofb -des-ede3-cfb -des-ede 3-ofb - desx -rc2-40-cbc -rc2-cfb - rc4 -aes-128-cfb -aes-128-ecb aes-192-cfb -aes-192-ecb -aes-256-cfb -aes-256-ecb -aes192 -bf-cbc -bf-ofb -cast-cbc -cast5-ecb -des-cbc -des-cfb8 -des-ede-cbc -des-ede3 -des-ede3-cfb1 -des-ofb - desx-cbc -rc2-64-cbc -rc-ecb - rc4-40 -aes-128-cfb1 -aes-128-ofb -aes-192-cfb1 -aes-192-0fb -aes-256-cfb1 -aes-256-ofb -aes 256 -bf-cfb -blowfish -cast5-cbc -cast5-ofb -des-cfb -des-ecb -des-ede-cfb -des-ede3-cbc -des-ede3-cfb8 - des 3 -rc2 -rc2-cbc -rc2-ofb 4. Assume that Alice sends a message of 640 bits encrypted using DES to Bob and that the 65th bit of the ciphertext is flipped during transmission. How many bits of the plaintext will be garbled at the Bob's side if the message is encrypted under ECB, CBC, 8-bit CFB, 8-bit OFB, and CTR modes, respectively? Explain your answers briefly. (total 10 points, 2 points for each mode) 2. Encryption using different ciphers and modes The algorithm seems to follow the pattern: (Algorithm name)-(key size)-(encryption mode) Noted: If the key size is omitted or excluded then it means there is only one key-size for that algorithm Algorithm name: Sometimes there is number included in the algorithm name whose usage is to distinguish the version of the algorithm; for instance, RC2 and RC4. Key size: key size is in bit. The longer the key the stronger your encryption is, but the slower operation it takes. Encryption mode: there are five main encryption mode that widely use in block cipher mode operation, Electronic Codebook (ECB), Cipher Block Chaining (CBC), Cipher Feedback (CFB), Output Feedback (OFB), and Counter (CTR) There are several encryption algorithm in OpenSSL as shown in image below. $ openssl enc --help -aes-128-cbc -aes-128-cfb8 -aes-192-cbc -aes-192-cfb8 -aes-256-cbc -aes-256-cfb8 -aes128 -bf -bf-ecb -cast -cast5-cfb -des -des-cfb1 -des-ede -des-ede-ofb -des-ede3-cfb -des-ede 3-ofb - desx -rc2-40-cbc -rc2-cfb - rc4 -aes-128-cfb -aes-128-ecb aes-192-cfb -aes-192-ecb -aes-256-cfb -aes-256-ecb -aes192 -bf-cbc -bf-ofb -cast-cbc -cast5-ecb -des-cbc -des-cfb8 -des-ede-cbc -des-ede3 -des-ede3-cfb1 -des-ofb - desx-cbc -rc2-64-cbc -rc-ecb - rc4-40 -aes-128-cfb1 -aes-128-ofb -aes-192-cfb1 -aes-192-0fb -aes-256-cfb1 -aes-256-ofb -aes 256 -bf-cfb -blowfish -cast5-cbc -cast5-ofb -des-cfb -des-ecb -des-ede-cfb -des-ede3-cbc -des-ede3-cfb8 - des 3 -rc2 -rc2-cbc -rc2-ofb 4. Assume that Alice sends a message of 640 bits encrypted using DES to Bob and that the 65th bit of the ciphertext is flipped during transmission. How many bits of the plaintext will be garbled at the Bob's side if the message is encrypted under ECB, CBC, 8-bit CFB, 8-bit OFB, and CTR modes, respectively? Explain your answers briefly. (total 10 points, 2 points for each mode)
