48 research outputs found
A proposed CCA-secure encryption on an ElGamal variant
No full textThis paper proposes a variant of the ElGamal public key cryptosystem which is secure against chosen ciphertext attack. Our proof of security is based on the intractability of the Gap Hashed Diffie-Hellman assumption in the standard model. The proposed scheme is practical to encrypt short messages such as credit card information, PIN code etc. This scheme also preserves the computational performance of the hash ElGamal encryption scheme (i.e. its simplistic algebraic construction, less exponentiation cost)
Elgamal digital signature scheme with integrated cfea-technique
No full textOne of the four security goals is authentication. Authentication is a mechanism to ensure that we are communicating with the intended party. If Alice and Bob want to communicate securely, then the authentication mechanism will be able to ensure that Alice is truly communicating with Bob, and Bob is truly communicating with Alice. This mechanism can be provided by the cryptography. One of the most established cryptography schemes is ElGamal cryptosystem. The original version of this cryptosystem is to provide confidentiality through encryption and decryption procedures. By manipulating these procedures, the authentication mechanism can be carried out. Thus, ElGamal Digital Signature Scheme emerges as one of the most popular authentication mechanisms. In order to provide good level of security, proper parameters must be used in this scheme. This includes the size of the parameters. Larger parameters will provide a better level of security. As a consequence, the performance of the scheme becomes an issue in real life application. In this paper, we proposed the enhancement of the ElGamal Digital Signature Scheme by integrating the Continued-Fraction-Euclidean-Algorithm (CFEA) technique. This technique is able to reduce the number of data to be processed in the signing and verification procedures. By integrating the CFEA-technique into the ElGamal Digital Signature Scheme, any number of documents can be compressed becomes a pair of documents. Therefore, the signing and verification procedures can be done in smaller number of steps
Hybrid Cryptosystem dengan Kriptografi Playfair Cipher dan Elgamal dan Steganografi Select Least Significant Bit
No full textData is a collection of facts, results of measurements, and observations in the form of numbers, words, and pictures. Data that is confidential and contains important information should not be known by many parties because it will harm other parties. To obtain such information, various unauthorized methods are usually used. As a result, data can be destroyed, altered, or even widely distributed, so that private data must be turned into public consumption. Therefore we need a system that can secure the data by applying cryptography. However, cryptography will generally experience suspicious data exchanges that invite the attention of unwanted parties. Therefore, a steganography technique is needed by inserting a message into the image so that the message is conveyed safely. Playfair cipher and ElGamal cryptographic algorithms are applied to encode the message and then inserted into the image using the LSB steganography algorithm. The test is carried out using one type of image, namely .bmp, and variations in message length, namely 50, 100, 200, 300, 400, and 500 characters. From the test, it was found that the ElGamal encryption resulted in the number of messages being twice as large as the original message, but the comparison between the Playfair cipher and ElGamal algorithms had encryption and decryption process times that always increased with the increase in the number of message characters being tested. Likewise, the time comparison between embedding and extraction has increased as the number of message characters increases. However, the size of the original image with the image that has been inserted the message is different, where the image that is inserted has a smaller file size than the original image.Data merupakan kumpulan fakta, hasil pengukuran dan observasi yang berupa angka, kata dan gambar. Data yang bersifat rahasia dan mengandung informasi penting tidak boleh diketahui oleh banyak pihak, karena akan merugikan pihak lain. Untuk mendapatkan informasi tersebut, berbagai metode yang tidak sah biasanya digunakan. Akibatnya, data dapat dihancurkan, diubah atau bahkan didistribusikan secara luas, sehingga data pribadi harus diubah menjadi konsumsi publik. Oleh sebab itu diperlukan sistem yang mampu mengamankan data tersebut yaitu dengan menerapkan kriptografi. Namun kriptografi umumnya akan mengalami pertukaran data yang mencurigakan sehingga mengundang perhatian pihak yang tidak diinginkan. Maka dari itu diperlukan Teknik steganografi dengan menyisipkan pesan kedalam gambar agar pesan tersebut tersampaikan dengan aman. Algoritma kriptografi playfair cipher dan elgamal diterapkan untuk menyandikan pesan dan kemudian disisipkan kedalam gambar dengan algoritma steganografi LSB. Pengujian dilakukan dengan menggunakan satu jenis gambar yaitu .bmp dan variasi panjang pesan yaitu 50, 100, 200, 300, 400, dan 500 karakter. Dari pengujian didapat hasil enkripsi ElGamal menghasilkan jumlah pesan yang besarnya dua kali lipat dari pesan asli namun perbandingan pada algoritma playfair cipher dan elgamal memiliki waktu proses enkripsi dan dekripsi yang selalu meningkat seiring bertambahnya jumlah karakter pesan yang diujikan. Begitu juga perbandingan waktu antara embedding dan extraction mengalami peningkatan seiring bertambahnya jumlah karakter pesan. Akan tetapi ukuran gambar asli dengan gambar yang telah disisipkan pesan mengalami perbedaan dimana gambar yang disisipkan gambar memiliki ukuran file yang lebih kecil daripada gambar asli.126 halamanSkripsi Sarjan
Perbandingan Kinerja Algoritma ElGamal dan Algoritma Multipower RSA Dalam Pengamanan File
No full textCurrently, the exchange of files in the virtual world is one of the things
that happen very often in our lives. There are times when a file is
confidential so there should be no other people who know the
information other than the intended person. Therefore, the method of
exchanging files over the internet should be made in such a way that no
one except receiver can take or steal the file. Thus, a high level of security
is also increasingly needed to avoid file theft during file process
exchange file. The security of data transmission can be solved using
Cryptography. Cryptographic use symmetric and asymmetric algorithms
data encryption. Many of the asimertis algorithms are used to secure data,
among them the ElGamal algorithm and the Multipower Rivest-Shamir-
Adelman algorithm. Both are asymmetric type cryptographic algorithms
that have private and public key pairs for encryption and decryption
processes. From the two algorithms above, a research is made to find out
which algorithm is more accurate by observing the running time and
algorithmic complexity, and the results obtained where ElGamal
algorithm has a process of encryption and decryption faster than the
process of encryption and decryption of Multipower Rivest-Shamir-
Adelman algorithm. The process of 100 character of encryption, the
ElGamal algorithm has an average time of encryption is 50.19394
millisecond, while the mean time of encryption algorithm of Multipower
Rivest-Shamir-Adelman is 432.86128 millisecond. For the decryption
process of 100 cipherkey, ElGamal algorithm has an average decryption
time of 0.58436 millisecond, while the mean time of decryption
algorithm of Multipower Rivest-Shamir-Adelman is 256.56554
millisecond. The result of the research on algorithm complexity gets the
result that ElGamal algorithm complexity is Ө (n2) and result of
Multipower Rivest-Shamir-Adelman algorithm complexity is Ө (n3). This
proves that the time complexity for the Multipower Rivest-Shamir-
Adelman algorithm is greater than the ElGamal algorithm thus affecting
running time.Saat ini, pertukaran file di dunia maya merupakan salah satu hal yang
sangat sering terjadi didalam kehidupan kita. Ada saat dimana suatu file
tersebut bersifat rahasia sehingga tidak boleh ada orang lain yang
mengetahui informasi selain orang yang dituju. Maka dari itu, metode
pertukaran file melalui internet harus dibuat sedemikian rupa sehingga
tidak ada orang lain selain orang yang dituju yang dapat mengambil
ataupun mencuri file tersebut. Dengan demikian, tingkat keamanan yang
tinggi juga semakin diperlukan untuk menghindari pencurian file pada
saat terjadinya proses pertukaran file. Keamanan pengiriman data dapat
diselesaikan dengan menggunakan Kriptografi. Penyandian kriptografi
data dapat menggunakan algoritma simetris dan asimetris. Banyak
algoritma asimertis yang digunakan untuk mengamankan data,
diantaranya adalah algoritma ElGamal dan algoritma Multipower
Rivest-Shamir-Adelman. Keduanya merupakan algoritma kriptografi
jenis asimetris yang memiliki pasangan kunci privat dan publik untuk
proses enkripsi dan dekripsi. Dari kedua algoritma diatas, dibuatlah
penelitian untuk mengetahui algoritma mana yang lebih akurat dengan
mengamati running time dan kompleksitas algoritmanya, dan didapatlah
hasil dimana algoritma ElGamal mempunyai proses enkripsi dan
dekripsi yang lebih cepat dibandingkan proses enkripsi dan dekripsi
algoritma Multipower Rivest-Shamir-Adelman. Untuk proses enkripsi
100 karakter, algoritma ElGamal mempunyai waktu rata-rata proses
enkripsi yaitu 50.19394 millisecond, sementara waktu rata-rata proses
enkripsi algoritma Multipower Rivest-Shamir-Adelman adalah
432.86128 millisecond. Untuk proses dekripsi 100 cipherkey, algoritma
ElGamal mempunyai waktu rata-rata proses dekripsi yaitu 0.58436
millisecond, sementara waktu rata-rata proses dekripsi algoritma
Multipower Rivest-Shamir-Adelman adalah 256.56554 millisecond.
Hasil penelitian pada kompleksitas algoritma mendapatkan hasil bahwa
kompleksitas algoritma ElGamal adalah Ө (n2) dan hasil kompleksitas
algoritma Multipower Rivest-Shamir-Adelman adalah Ө (n3). Hal ini
membuktikan bahwa kompleksitas waktu untuk algoritma Multipower
Rivest-Shamir-Adelman lebih besar dari algoritma ElGamal sehingga
mempengaruhi running time.Skripsi Sarjan
A Security-Mediated Encryption Scheme Based on ElGamal Variant
No full textBoneh et al. introduced mediated RSA (mRSA) in 2001 in an attempt to achieve faster key revocation for medium-sized organizations via the involvement of a security mediator (SEM) as a semi-trusted third party to provide partial ciphertext decryption for the receiver. In this paper, a pairing-free security mediated encryption scheme based on an ElGamal variant is proposed. The scheme features a similar setting as in the mediated RSA but with a different underlying primitive. We show that the proposed security mediated encryption scheme is secure indistinguishably against chosen-ciphertext attack (IND-CCA) in the random oracle via the hardness assumption of the computational Diffie-Hellman (CDH) problem
Complete recovery of severe quadriparesis caused by stab wound at the craniocervical junction
No full textElgamal, Essam A.,
Neurosurgery Division, Surgery Department (37), College of
Medicine, King Khalid University Hospital,
PO Box 7805 Riyadh 11472, Saudi Arabia
e-mail: [email protected]
Tel.: +966-1-4671273
Fax: +966-1-4679493Non-missile penetrating spinal cord injuries are uncommon, and involvement of the craniocervical junction is even less frequent. The author reports a case of 42-
year-old male who presented with quadriparesis immediately following stab injury inflicted with a kitchen knife to
the back of his neck. The knife was retained in the patient’s neck. Neurological examination revealed spastic
paraplegia and severe weakness of the left upper limb and the right-hand grip, and sensory disturbance from C2 and
downwards. In addition to these symptoms, cerebrospinal fluid (CSF) was leaking from the wound. Computerised tomography (CT) scan showed the blade passed through
the spinal canal and its tip reached the odontoid peg. After retrieval of the knife, his quadriparesis recovered. The
management and outcome of the patient are described
Digital File Signcryption with Benaloh Algorithm and Elgamal Signature Scheme
No full textThe rapid advancement of technology makes it easier for individuals to send files
digitally, but it also increases cases of file forgery and duplication, for example in the evoting
process. To prevent this, it is necessary to implement a cryptographic system,
one of which is through signcryption. E-voting emphasizes authentication, data
integrity, and confidentiality. Therefore, research was conducted on the Benaloh and
ElGamal Signature Scheme algorithms in signcryption methods to overcome these
problems and provide integrity, confidentiality, and authentication to e-voting data
transmission. Both signature schemes use the modular exponential method, which is
more efficient than the RSA factorization. The final results show the success of the
signcryption process with test results in the form of running time of each Signcription
process for each file type and size and cryptanalysis testing with Brute Force Attack.73 PagesTesis Magiste
CASH on Modified Elgamal: A Preventive Technique for False Channel Condition Reporting Attackin Ad-hoc Network
No full textAbstractAd-hoc networks are wireless networks, where the nodes transmit data through other nodes. Many Wireless networks exploit channel condition for routing. Such protocols are known as channel aware protocols. In channel aware protocols, each node reports its channel condition to other nodes and other nodes give its channel condition. However these protocols are vulnerable to false channel condition reporting attack. In this paper, an efficient Coordinate ASH (CASH) algorithm on Modified elgamal signature is proposed to avoid false channel condition reporting attack. Message authentication is ensured by adding signature and this signature is added to routing messages. Analysis demonstrates that proposed scheme is better than current schemes with respect to Computational time
Penerapan Enkripsi Menggunakan Metode Elgamal guna Meningkatkan Keamanan Data
No full textData security is very important in maintaining the confidentiality of information, especially those containing sensitive information whose contents should only be known by the entitled people. especially if the transmission is done through a public network, if the data is not secured beforehand, it will be very easy to be intercepted and the contents of the information known by irresponsible people. One of the methods used to secure data is to use a cryptographic system, namely by providing the information content (plaintext) into content that is not understood through the encryption process, and to retrieve the original information, a description process is carried out, accompanied by using the correct key. Therefore, the author recommends the Elgamal algorithm to be able to provide security for text data. The reason the author uses the ElGamal algorithm is that the ElGamal algorithm is part of asymmetric cryptography where the formation of one of the keys uses prime numbers and focuses on the strength of the key in solving discrete logarithm problems
On the uniformity of distribution of the elliptic curve ElGamal signature
No full textWe show that, under some natural conditions, the pairs (ρ, σ) produced by the elliptic curve ElGamal signature scheme are uniformly distributed. In particular, this implies that values of ρ and σ are not correlated. The result is based on some new estimates of exponential sums. For the ElGamal signature over a finite field, a similar result has been obtained by the second author.8 page(s
