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In the ElGamal cryptosystem, a plaintext is encrypted as, where is the public key.
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ElGamal and cryptosystem
The ElGamal cryptosystem, invented by Taher ElGamal.
The ElGamal cryptosystem is usually used in a hybrid cryptosystem.
I. e., the message itself is encrypted using a symmetric cryptosystem and ElGamal is then used
Cunningham chains are now considered useful in cryptographic systems since " they provide two concurrent suitable settings for the ElGamal cryptosystem ... can be implemented in any field where the discrete logarithm problem is difficult.
In 1985, Elgamal published a paper titled A Public key Cryptosystem and A Signature Scheme based on discrete Logarithms in which he proposed the design of the ElGamal discrete log cryptosystem and of the ElGamal signature scheme.
* LUC is a public-key cryptosystem based on Lucas sequences that implements the analogs of ElGamal ( LUCELG ), Diffie-Hellman ( LUCDIF ), and RSA ( LUCRSA ).
ElGamal and plaintext
ElGamal encryption is probabilistic, meaning that a single plaintext can be encrypted to many possible ciphertexts, with the consequence that a general ElGamal encryption produces a 2: 1 expansion in size from plaintext to ciphertext.
ElGamal and is
In cryptography, the ElGamal encryption system is an asymmetric key encryption algorithm for public-key cryptography which is based on the Diffie – Hellman key exchange.
ElGamal encryption is used in the free GNU Privacy Guard software, recent versions of PGP, and other cryptosystems.
The Digital Signature Algorithm is a variant of the ElGamal signature scheme, which should not be confused with ElGamal encryption.
ElGamal encryption is unconditionally malleable, and therefore is not secure under chosen ciphertext attack.
DSA is a variant of the ElGamal Signature Scheme.
DSA is similar to the ElGamal signature scheme.
In contrast, the Cramer-Shoup system ( which is based on ElGamal ) is not malleable.
In the Paillier, ElGamal, and RSA cryptosystems, it is also possible to combine several ciphertexts together in a useful way to produce a related ciphertext.
Elgamal is sometimes written as El Gamal or ElGamal, but Elgamal is now preferred.
It is an ElGamal variant, similar to the Digital Signature Algorithm and GOST R 34. 10-94.
It is used as the basis to prove the security of many cryptographic protocols, most notably the ElGamal and Cramer – Shoup cryptosystems.
ElGamal and public
Some special and specific algorithms have been developed to aid in attacking some public key encryption algorithms-both RSA and ElGamal encryption have known attacks that are much faster than the brute-force approach.
ElGamal and key
PGP 3 introduced use of the CAST-128 ( a. k. a. CAST5 ) symmetric key algorithm, and the DSA and ElGamal asymmetric key algorithms, all of which were unencumbered by patents.
ElGamal encryption consists of three components: the key generator, the encryption algorithm, and the decryption algorithm.
* ElGamal encryption, an asymmetric key encryption algorithm for public-key cryptography
ElGamal and .
ElGamal encryption can be defined over any cyclic group.
The security of the ElGamal scheme depends on the properties of the underlying group as well as any padding scheme used on the messages.
ElGamal achieves semantic security.
Other schemes related to ElGamal which achieve security against chosen ciphertext attacks have also been proposed.
Encryption under ElGamal requires two exponentiations ; however, these exponentiations are independent of the message and can be computed ahead of time if need be.
cryptosystem and plaintext
A backdoor in a computer system ( or cryptosystem or algorithm ) is a method of bypassing normal authentication, securing remote access to a computer, obtaining access to plaintext, and so on, while attempting to remain undetected.
A cryptosystem may be semantically secure against chosen plaintext attacks or even non-adaptive chosen ciphertext attacks ( CCA1 ) while still being malleable.
In the RSA cryptosystem, a plaintext is encrypted as, where is the public key.
In a cryptosystem, weaknesses can be introduced through insecure handling of plaintext, allowing an attacker to bypass the cryptography altogether.
Older systems used techniques such as padding and Russian copulation to obscure information in plaintext that could be easily guessed, and to resist the effects of loss of plaintext on the security of the cryptosystem.
A backdoor in a computer system ( or cryptosystem or algorithm ) is a method of bypassing normal authentication, securing remote access to a computer, obtaining access to plaintext, and so on, while attempting to remain undetected.
The Rabin cryptosystem was the first asymmetric cryptosystem where recovering the entire plaintext from the ciphertext could be proven to be as hard as factoring.
The great advantage of the Rabin cryptosystem is that a random plaintext can be recovered entirely from the ciphertext only if the codebreaker is capable of efficiently factoring the public key n. Note that this is a very weak level of security.
This cryptosystem is provably secure ( in a strong sense ) against chosen plaintext attacks.
In cryptography, a cryptosystem is semantically secure if an adversary who knows the encryption algorithm and is in possession of a ciphertext is unable to determine any information about the plaintext.
For an asymmetric key encryption algorithm cryptosystem to be semantically secure, it must be infeasible for a computationally bounded adversary to derive significant information about a message ( plaintext ) when given only its ciphertext and the corresponding public encryption key.
The underlying cryptosystem is IND-CPA ( and thus semantically secure under chosen plaintext attack ) if the adversary cannot determine which of the two messages was chosen by the oracle, with probability significantly greater than ( the success rate of random guessing ).
A deterministic encryption scheme ( as opposed to a probabilistic encryption scheme ) is a cryptosystem which always produces the same ciphertext for a given plaintext and key, even over separate executions of the encryption algorithm.
However, it is not an efficient cryptosystem, as ciphertexts may be several hundred times larger than the initial plaintext.
The GM cryptosystem leverages this asymmetry by encrypting individual plaintext bits as either random quadratic residues or non-residues modulo N, all with quadratic residue symbol + 1.
Certain schemes, such as Cocks Identity Based Encryption, or the Goldwasser-Micali cryptosystem result in ciphertexts hundreds or thousands of times longer than the plaintext.
0.110 seconds.