DES follows In the DES algorithm the round key is __________ bit and the Round Input is ____________bits. The basic idea is show in figure. A final permuatation(inverse of P) is applied to (R16,L16) to yield ciphertext a) Scaling of the existing bits However double DES uses 112 bit key but gives security level of 2^56 not 2^112 and this is because of meet-in-the middle attack which can be used to break through double DES. Furthermore, different types of cryptosystems require vastly different … Triple DES: Triple DES is a encryption technique which uses three instance of DES on same plain text. b) 32 Bits d) Addition of ones The DES Algorithm Cipher System consists of ____________rounds (iterations) each with a round key In general, Triple DES with three independent keys (keying option 1) has a key length of 168 bits (three 56-bit DES keys), but due to the meet-in-the-middle attack, the effective security it provides is only 112 bits. 13. View Answer, 9. The use of a deprecated algorithm means that the algorithm or key length may be used if the risk of doing so is acceptable. If you are looking for a reviewer in datacom, topic in Electronics Systems and Technologies (Communications Engineering) this will definitely help you before taking the Board Exam. Search Google: Answer: (c). Join our social networks below and stay updated with latest contests, videos, internships and jobs! DES is really the standard, and DEA is the algorithm. b) False a) 8 Works with 144 bit blocks of plain text and applies DES algorithm once. Each algorithm is designed to accept a certain key length. b) False We have mention that DES uses a 56 bit key. The key length is 56 bits. Uses 128 bit blocks of plain text and 112 bit keys and apply DES algorithm thrice. SHA 1: Secure Hash Algorithm 1 is a cryptographic hash function in cryptography. In the DES algorithm, although the key size is 64 bits only 48bits are used for the encryption procedure, the rest are parity bits. Others Each other Keys Data . The questions asked in this NET practice paper are from various previous year papers. The algorithms available will most likely be different for each CSP. d) 32, 32 This set of Cryptography Multiple Choice Questions & Answers (MCQs) focuses on “The Data Encryption Standard (DES) and It’s Strength”. What is the size of the key in the SDES algorithm? Strength of algorithm (b) Secrecy of key (c) Length of key (d) All of the above ( ) 24. During decryption, we use the Inverse Initial Permutation (IP-1) before the IP. The DES Algorithm Cipher System consists of _____rounds (iterations) each with a round key a)12 b)18 c)9 d)16 Answer:d Explanation: The DES Algorithm Cipher System consists of 16 rounds (iterations) each with a round key. a) 12 In the DES algorithm the Round Input is 32 bits, which is expanded to 48 bits via ____________ DES takes input as 64-bit plain text and 56-bit key to produce 64-bit Ciphertext. b) 64,32 Data Encryption Standard (DES) An older type of block cipher selected by the United States federal government back in the 1970s as its encryption standard; due to its weak key… Though, key length is 64-bit, DES has an effective key length of 56 bits, since 8 of the 64 bits of the key are not used by the encryption algorithm (function as check bits only). Furthermore, DES can be a victim of attack using the linear cryptanalysis. Remember that DEA is the algorithm used for the DES standard, so DEA also has a true key size of 56 bits, because we are actually talking about the same algorithm here. A RSA public key consists in several (big) integer values, and a RSA private key consists in also some integer values. Here, we have a set of multiple-choice questions and answers (quiz) on cryptography basics (basic concepts of cryptography techniques). hProv A HCRYPTPROV handle of a CSP created by a call toCryptAcquireContext. Common key sizes are: DES: 56bit key; AES: 128-256bit key (commonly used values are 128, 192 and 256) RSA (assymetric cryptography): 1024, 2048, 4096 bit key b) Duplication of the existing bits AES vs. DES. If the 3DES key is 192 bits (which has a key strength of 168 bits) k1 = key[0..7] k2 = key[8..15] k3 = key[16..23] So if we have a 64-bit 3DES key we encrypt with the key, then decrypt with the key (returning the original data) and then encrypt with the key again. 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