# Elgamal cryptosystem

Xem 1-7 trên 7 kết quả Elgamal cryptosystem
• ### ASYMETRIC-KEY CRYPTOGRAPHY

TRAPDOOR ONE-WAY FUNCTIONThe main idea behind asymmetric-key cryptography is the concept of the trapdoor one-way function. TrapdoorOne-WayFunction(TOWF) One-WayFunction(OWF) 1.fiseasytocompute. 2. f −1 is difficult to compute. 3. Given y and a trapdoor, x can be computed easily.

• ### Using Modern Symmetric Key Ciphers

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. Error Propagation A single bit error in transmission can create errors in several in the corresponding block.

• ### Using Modern Symmetric unkey Ciphers

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.

• ### MODERN CIPHERS FULL

How many padding bits must be added to a message of 100 characters if 8bit ASCII is used for encoding and the block cipher accepts blocks of 64 bits? Suppose that we have a block cipher where n = 64. If there are 10 1’s in the ciphertext, how many trialanderror tests does Eve need to do to recover the plaintext from the intercepted ciphertext in each of the following cases?

• ### MODERN CIPHERS

How many padding bits must be added to a message of 100 characters if 8-bit ASCII is used for encoding and the block cipher accepts blocks of 64 bits? 1 MODERN BLOCK CIPHERS Substitution or Transposition ? To be resistant to exhaustive-search attack, a modern block cipher needs to be designed as a substitution cipher. Suppose that we have a block cipher where n = 64. If there are 10 1’s in the ciphertext, how many trial-and-error tests does Eve need to do to recover the plaintext from the intercepted ciphertext in each of the following cases? a. The cipher is designed as a...

• ### Phát triển một số thuật toán mật mã khóa công khai - Lưu Hồng Dũng

Bài báo đề xuất một số thuật toán mật mã khóa công khai được phát triển từ hệ mật ElGamal. Ưu điểm của các thuật toán mới đề xuất là cho phép bảo mật và xác thực thông tin một cách đồng thời. Hơn nữa, mức độ an toàn của các thuật toán mới đề xuất không nhỏ hơn mức độ an toàn của thuật toán ElGamal.