IMPLEMENTASI ALGORITMA SCHMIDT-SAMOA PADA ENKRIPSI DEKRIPSI EMAIL BERBASIS ANDROID

2013 ◽  
Vol 9 (1) ◽  
Author(s):  
Willy Ristanto ◽  
Willy Sudiarto Raharjo ◽  
Antonius Rachmat Chrismanto

Cryptography is a technique for sending secret messages. This research builds an Android-based email client application which implement cryptography with Schmidt-Samoa algorithm, which is classified as a public key cryptography. The algorithm performs encryption and decryption based on exponential and modulus operation on text messages. The application use 512 and 1024 bit keys. Performance measurements is done using text messages with character number variation of 5 – 10.000 characters to obtain the time used for encryption and decryption process. As a result of this research, 99,074% data show that decryption process is faster than encryption process. In 512 bit keys, the system can perform encryption process in 520 - 18.256 miliseconds, and decryption process in 487 - 5.688 miliseconds. In 1024 bit keys, system can perform encryption process in 5626 – 52,142 miliseconds (7.388 times slower than 512 bit keys) and decryption process with time 5463 – 15,808 miliseconds or 8.290 times slower than 512 bit keys.

Author(s):  
Keith M. Martin

In this chapter, we introduce public-key encryption. We first consider the motivation behind the concept of public-key cryptography and introduce the hard problems on which popular public-key encryption schemes are based. We then discuss two of the best-known public-key cryptosystems, RSA and ElGamal. For each of these public-key cryptosystems, we discuss how to set up key pairs and perform basic encryption and decryption. We also identify the basis for security for each of these cryptosystems. We then compare RSA, ElGamal, and elliptic-curve variants of ElGamal from the perspectives of performance and security. Finally, we look at how public-key encryption is used in practice, focusing on the popular use of hybrid encryption.


Author(s):  
Sabitha S ◽  
Binitha V Nair

Cryptography is an essential and effective method for securing information’s and data. Several symmetric and asymmetric key cryptographic algorithms are used for securing the data. Symmetric key cryptography uses the same key for both encryption and decryption. Asymmetric Key Cryptography also known as public key cryptography uses two different keys – a public key and a private key. The public key is used for encryption and the private key is used for decryption. In this paper, certain asymmetric key algorithms such as RSA, Rabin, Diffie-Hellman, ElGamal and Elliptical curve cryptosystem, their security aspects and the processes involved in design and implementation of these algorithms are examined.


Aadhaar database is the world's largest biometric database system. The security of Aadhaar database plays a major role. In order to secure such huge database, an encryption and decryption algorithm has been proposed in this paper. Elliptic Curve Cryptography (ECC) is a public key cryptography which is used to provide high security to those databases. The Aadhaar database contains individual personal information as well as their biometric identities. ECC is widely used for providing security to all kinds of data. ECC has smaller key size, fast computation, high throughput compared to other cryptographic algorithms. The data’s present in database are converted into their corresponding Pixel or ASCII values. After that the encryption process is done with the help of public key, private key, generation points and plain text. After the encryption process, the encrypted coordinates can be mapped with the generated points and from that corresponding ASCII value for text, pixel value for image can be retrieved. Then, the alphabet which is corresponding to ASCII will be displayed so that the cipher text can be viewed. This encrypted data is stored in the database. In order to retrieve the original data decryption process using ECC is carried out. In decryption process, receiver’s private key and cipher coordinates which is retrieved from encryption process are used. Therefore, the personal details of an individual can be retrieved with the presence of that particular person who only knows that private key. So, the hackers will not be able to retrieve the database of any individual just by knowing their Aadhaar ID. The proposed work is implemented in the MATLAB software. The Performance metrics like PSNR, Similarity, Correlation Coefficient, NPCR and UACI has been done for analysis.


Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2864 ◽  
Author(s):  
Utku Gulen ◽  
Abdelrahman Alkhodary ◽  
Selcuk Baktir

As wireless sensor networks (WSNs) become more widespread, potential attacks against them also increase and applying cryptography becomes inevitable to make secure WSN nodes. WSN nodes typically contain only a constrained microcontroller, such as MSP430, Atmega, etc., and running public key cryptography on these constrained devices is considered a challenge. Since WSN nodes are spread around in the field, the distribution of the shared private key, which is used in a symmetric key cryptographic algorithm for securing communications, is a problem. Thus, it is necessary to use public key cryptography to effectively solve the key distribution problem. The RSA cryptosystem, which requires at least a 1024-bit key, is the most widely used public key cryptographic algorithm. However, its large key size is considered a drawback for resource constrained microcontrollers. On the other hand, RSA allows for extremely fast digital signature generation which may make it desirable in applications where messages transmitted by sensor nodes need to be authenticated. Furthermore, for compatibility with an existing communication infrastructure, it may be desirable to adopt RSA in a WSN setting. With this work, we show that, in spite of its long key size, RSA is applicable for wireless sensor networks when optimized arithmetic, low-level coding and some acceleration algorithms are used. We pick three versions of the MSP430 microcontroller, which is used widely on wireless sensor network nodes, and implement 1024-bit RSA on them. Our implementation achieves 1024-bit RSA encryption and decryption operations on MSP430 in only 0 . 047 s and 1 . 14 s, respectively. In order to achieve these timings, we utilize several acceleration techniques, such as the subtractive Karatsuba-Ofman, Montgomery multiplication, operand scanning, Chinese remainder theorem and sliding window method. To the best of our knowledge, our timings for 1024-bit RSA encryption and decryption operations are the fastest reported timings in the literature for the MSP430 microcontroller.


Author(s):  
Eko Hariyanto Hariyanto ◽  
Muhammad Zarlis ◽  
Darmeli Nasution Nasution ◽  
Sri Wahyuni

 Security of RSA cryptography lied in the difficulty of factoring the number p and q bacame the prime factor. The greater the value of p and q used, the better the security level was. However, this could result in a very slow decryption process. The most commonly used and discussed method of speeding up the encryption and decryption process in RSA was the Chinese Remainder Theorem (CRT). Beside that method, there was another method with the same concept with CRT namely Aryabhata Remainder Theorem which was also relevant used in public key cryptography such as RSA. The purpose of this study was to obtain an effective method to RSA especially in the decryption process based on the calculation of the time complexity of computing.


2020 ◽  
pp. 39-52
Author(s):  
admin admin ◽  
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In this article, our main focus is to put forward the concept of Cryptography in terms of triangular neutrosophic numbers. This kind of cryptography is really reliable, manual, secure, and based on few simple steps. All the encryption and decryption are easy to proceed (mention below). As we know, Public-key cryptography as an indefatigable defender for human privacy and use as information transfer from the ages. various concepts are available with regard to cryptography e.g. Elliptic curve cryptography. TNNC (Triangular neutrosophic numbers cryptography) is familiar with basic concepts of math as well as applicable in different situations e.g. code cryptography, detailed view cryptography, and Graph cryptography encryption facilitate.


2017 ◽  
Vol 43 (1) ◽  
pp. 22-27
Author(s):  
Ammar Ali ◽  
Ali Sagheer

In this paper, a secure chatting application with end to end encryption for smart phones that used the android OS has beenproposed. This is achieved by the use of public key cryptography techniques. The proposed application used the Elliptic Curve DiffieHellman Key Exchange (ECDH) algorithm to generate the key pair and exchange to produce the shared key that will be used for theencryption of data by symmetric algorithms. The proposed Application allows the users to communicate via text messages, voicemessages and photos. For the text message security the standard AES algorithm with a 128 bit key are used. The generated key (160 bit)minimized to 128 bit length by selecting the first 128 bit of the generated key in order to be used by the AES algorithm. For the voice andimage security processes the proposed application used the symmetric algorithm RC4 for this purpose.


2017 ◽  
Vol 9 (1) ◽  
pp. 30-35
Author(s):  
Sunderi Pranata ◽  
Hargyo Tri Nugroho ◽  
Hirofumi Yamaki

It is known that password itself is not enough for formidable authentication method since it has a lot of vulnerabilities. Multi factor authentication (MFA) is introduced for the next generation for good authentication to address that issue. MFA combines two or more of three principles of good security, “something you know”, “something you have”, and “something you are”. Most MFA mechanisms work as one time passwords (OTP). However, they can still be vulnerable to phishing and MiTM attack. On top of that, OTP can be hard to use as it requires user to input another password given by the device (SMS, token, authenticator). Implemented in small USB U2F device, FIDO U2F delivers easier yet stronger security on authentication process which implements public key cryptography, challenge-response protocol, and phishing and MitM protection.  Index Terms— Authentication protocol, FIDO U2F, Multi factor authentication, OTP


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