is elgamal secure

Now, RSA patents have expired. The one use case where I see ElGamal being used over RSA is when a multiplicatively homomorphic cryptosystem is needed (noe that both ElGamal and RSA are multiplicatively homomorphic). As this title suggests the security of this cryptosystem is based on the notion of discrete logarit For example, given an encryption of some (possibly unknown) message , one can easily construct a valid encryption of the message . It all depends on what padding scheme is used. The Diffie-Hellman key exchange provides a method of sharing a secret key between Alice and Bob, but does not allow Alice and Bob to otherwise communicate securely. It can be considered as the asymmetric algorithm where the encryption and decryption happen by the use of public and private keys. The ElGamal cryptographic algorithm is comparable to the Diffie-Hellman system. ElGamal encryption is unconditionally malleable, and therefore is not secure under chosen ciphertext attack. As for ElGamal versus RSA: An encrypted ElGamal message is simply about twice the size of an encrypted RSA message for the same security level. While ElGamal over appropriate prime order subgroups is semantically secure and ElGamal over ∗ is not we should not conclude that any ElGamal implementation using the group ∗ is immediately insecure and any system using a prime order subgroup is secure. DSA and Elgamal; RSA (Sign only) DSA (Sign only) I found this Superuser question, but it may be outdated. Stick to RSA. The ElGamal cryptographic algorithm is a public key system like the Diffie-Hellman system. Erik-Oliver Blass and I found that the implementations of ElGamal encryption in libgcrypt, PyCrypto, PyCryptodome, and CryptoPP are not secure. • We can use the above fact to come up with two message where one of them is a quadratic residue and the other one is a quadratic non-residue so that The cryptosystem takes its name from its founder the Egyptian cryptographer Taher Elgamal who introduced the system in his 1985 paper entitled " A Public Key Cryptosystem and A Signature Scheme Based on Discrete Logarithms ". • We can infer whether a ciphertext is quadratic residue or not. It is mainly used to establish common keys and not to encrypt messages. Diffie-Hellman (DH) is a key agreement algorithm, ElGamal an asymmetric encryption algorithm. Semantic Security of ElGamal • Note that the generic ElGamal encryption scheme is not semantically secure. Notably, ElGamal is homomorphic (given the encryption of x and the encryption of y, one can from the outside compute the encryption of the product xy), which is a nice property in some cases, but can be bothersome in other conditions. Nowadays, RSA is more convenient but not necessarily safer than ElGamal. RSA keys seem to be less secure since it's known that the NSA infiltrated RSA and made their key generation algorithm weaker. ElGamal is a public key encryption algorithm that was described by an Egyptian cryptographer Taher Elgamal in 1985. ElGamal encryption is an example of public-key or asymmetric cryptography. I don't know if this has a significant influence for a 4096 bit RSA key. Diffie-Hellman enables two parties to agree a common shared secret that can be used subsequently in a symmetric algorithm like AES. Introduction. Be cyber secure. The ElGamal cryptosystem was first described by Taher Elgamal in 1985 and is closely related to the Diffie-Hellman key exchange. 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