Robbi Rahim

Internet Protocol Security (IP Security) is a security protocol that serves to secure information in the event of an exchange on the internet. It happens if there is a connection between private IP and public IP. This protocol will exchange packets on the IP layer safely. It provides two types of encryption options, transport, and tunnel. Transport mode will encrypt the data section without changing the packet header. The algorithm used to encrypt data is a symmetric cryptography algorithm. This protocol authenticates and encrypts every packet from a data transmission session. Also, it can generate keys between the sender and the recipient at the first time it is activated and can negotiate the cryptographic keys that will be used during the session. IP Security is an end-to-end cryptosystem that works at the internet layer of the Internet Protocol Suite. The protocol serves to protect the data flow in host-to-host, network-to-network, and network-to-host as well.

Stages of decision making done by the manager is a crucial stage. Given the resulting decisions affect the sustainability of the organization, then many managers use systems that can support the resulting decisions. This system is known as the decision support system, which applies to solving a problem, using methods such as ELECTRE, Promethee, SAW, TOPSIS. Using decision support systems makes it easy for decision makers to add new data, change data and make decisions more efficiently. In this article, the method used is Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). I. INTRODUCTION The development of today's computer technology tools is widely developed. It starts with the development of computers to mobile-based technology devices. Now the application of computers in providing appropriate information and used to support decisions to be made by a leader increasingly in demand. Decision support systems as a CBIS are the right tools, dedicated to managers in support of its decision. The application of decision support system methods in generating a decision using several criteria and alternatives. Each criterion is given the weight that corresponds to the interests of the problems encountered. The application of methods to decision-making is common in some cases, choosing the best lecturers by applying ELECTRE[1], computing tuition fees using Fuzzy Tsukamoto[2], student selection using the Composite Performance Indexc[3] and much more SPK applications to assist managers or managers in decision making. Some methods of MADM are also capable of solving problems on decision making such as COPRAS, WSM, SAW, WP, EXPROM II[4][5], but in the following study, the author uses Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method. TOPSIS is one of the decisions making methods that can choose the best alternative from some alternatives. The basic concept of the Technique for Order Performance by Similarity to Ideal Solution (TOPSIS) method is that the best-selected alternative not only has the shortest distance from the ideal solution (the best solution) but also has the longest distance from the ideal negative solution (worst solution)[6][7]. From the results of the process using TOPSIS method, can provide effective information for managers in support of the decision made that is close to the best possible and far from the worst. Utilization of decision support systems in management is expected to make more efficient decisions generated by decision makers so that the final result (alternative) is selected the right and better decision.

The concealment of information in the image can be done with some specific techniques. One of the techniques used is End of File. In the insertion of this information, a series of characters will be converted to ASCII code and each byte will be inserted at the end of the RGB image in descending order. The insertion can be done in Red, Green, Blue or on all of them. The downside of this insertion is that if the bits are extracted in sequence, this will produce the original information that has been previously inserted. In large data usage with a limited number of pixels, the stego image will display an oddity. To make the information more secure, an encryption technique needs to be applied. The encryption used is Vernam. This method has very high speed. The data embedded in the image will be more secure.

Digital Forensics is a technique used to search for evidence of events that have occurred. This quest aims to reveal the hidden truth. The existence of digital forensic activities due to the occurrence of crimes both in the field of computers or other. Legal treatment in digital forensic field makes this area of science a compulsory device to dismantle crimes involving the computer world. In general, the cyber crime leaves a digital footprint, so it is necessary for a computer forensics expert to secure digital evidence. Computer forensics necessarily requires a standard operational procedure in taking digital evidence so as not to be contaminated or modified when the data is analyzed. The application of digital forensic is beneficial to the legal process going well and correctly.

Rabin-Karp is one of the algorithms used to detect the similarity levels of two strings. In this case, the string can be either a short sentence or a document containing complex words. In this algorithm, the plagiarism level determination is based on the same hash value on both documents examined. Each word will form K-Gram of a certain length. The K-Gram will then be converted into a hash value. Each hash value in the source document will be compared to the hash value in the target document. The same number of hashes is the level of plagiarism created. The length of K-Gram is the determinant of the plagiarism level. By determining the proper length of K-Gram, it produces the accurate result. The results will vary for each K-Gram value.

With the changing of the times, information is crucial today especially for technological developments, especially in data security systems. In maintaining data security, there is a branch of science in its development, namely cryptography. Classical cryptography as vigenere cipher is a cryptographic algorithm implementation is very simple but quite powerful in his era. Having discovered methods kasiski, vigenere cipher algorithm is very easy to be analyzed by cryptanalyst to get a key. This is due to the relationship between the cipher, plaintext, and the key cryptography. The core used is usually composed of some characters arrangement either letters or numbers that are not too long, so it is easy to remember. So as to facilitate cryptanalyst to determine the key cryptography. To that end, the key must be an array of random characters long, so that the relationship between plaintext, ciphertext and key becomes very apparent that it would be difficult to solve by cryptanalyst. Which is the key arrangement of random characters that can obtain the pixel values of an image that being converted into ASCII characters? The pixel values of 8-bit grayscale images ranging from 0-255 equal the number of characters in the ASCII table. So that all pixel values in an 8-bit grayscale image can be converted into random characters and can be used as a key for the Vigenere Cipher Algorithm.

Decision support system is part of computer-based information systems used to support decision-making in an organization or company, and the decision support could be generated by using several kinds of methods, one of which is a method of Composite Performance Index (CPI). Composite Performance Index can be used to determine the determination or ranking of various alternatives based on several criteria and is expected to use the Composite Performance Index (CPI) the acceptance of new students more effectively so that students quickly get information about the admissibility of the student candidates. 1. INTRODUCTION Acceptance of student activities conducted by educational and non-educational institutions. In particular, educational institutions provide some criteria for the acceptance of students each year. Selection of new students is a way, the process, the selection or screening of students in the academic ability is the best candidate for the learning sector in educational institutions that need to be determined quickly and precisely matches or meets the acceptance criteria as appropriate in each institution. Decision support system is generating system information [1] [2] [3] aimed at a specific problem to be solved by policy makers in decision making [4] [5] [6] [7]. Decision support systems are an integral part of the totality of the organization's overall system [4] [8] [9] [10] [11]. Composite Performance Index can be used to determine the ranking of various alternatives based on criteria for decision-making using intuitive and analytical [12]. Decisions are taken intuitively be precise when making decisions in similar situations and had done the previous analysis. Analysis precedes decisions requires a longer time because of the need for proper data and appropriate processing methods proposed so that decisions can be implemented properly [12].

Vigenere chipper is one standard cryptographic algorithm, this algorithm very simple to use substitution as in Caesar cipher to encode the message text. One disadvantage of an extended vigenere key cipher which can determine by using a method, the method kasiski. in vigenere cipher, phrases 4/E: in the ciphertext generated from the encryption process so that the method kasiski can determine the encoded text. Goldbach codes algorithm is an algorithm for compression, which will be used to address the weaknesses in vigenere cipher. In this paper will try to discuss security with vigenere ciphertext, then ciphertext produced will be processed again using algorithms Goldbach codes. By applying the algorithm, Goldbach codes the result from the course of securing data using vigenere Chipper becomes harder to guess the original text despite using methods kasiski due to be acquired is the message of a different character.

Noise is one form of issue in the image, salt & pepper noise is the kind of noise that can be made using a special technique or also due to the conversion from analog signals to digital, the noise can be improved by using algorithms such as the mean filtering, the mid-point filtering and median filtering, median filtering algorithm is widely used for repair image quality, this article will discuss the modification of the median filtering to improve noise in the image by taking the average of neighboring pixels by 2 points from the value of the center clockwise, the value is taken to be processed to retrieve the value of the middle and then the overall result value will be divided to replace the center pixel value 3x3 spatial window

Genetic algorithms can solve complex problems, including the problems of cryptography. What problems often occur on the Hill Cipher is the waste of time to determine the numbers that are used in the encryption process. In the encryption process, it is not a problem if the key is derived from any number. However, the problem is ciphertext cannot be returned to the original message. The key that is used must have the determinant is 1. To find the value of it is something that takes time if it must be done manually. Due to the entered value to the Hill Cipher is random, Genetic algorithms can be used to optimize the search time. By using this algorithm, the determinant calculation will be more accurate and faster. The result achieved is the program can specify some combination of numbers that can be used as the encryption key Hill Cipher and it can reject the unnecessary numbers.

Digital Forensics is a technique used to search for evidence of events that have occurred. This quest aims to reveal the hidden truth. The existence of digital forensic activities due to the occurrence of crimes both in the field of computers or other. Legal treatment in digital forensic field makes this area of science a compulsory device to dismantle crimes involving the computer world. In general, the cyber crime leaves a digital footprint, so it is necessary for a computer forensics expert to secure digital evidence. Computer forensics necessarily requires a standard operational procedure in taking digital evidence so as not to be contaminated or modified when the data is analyzed. The application of digital forensic is beneficial to the legal process going well and correctly.

Internet Protocol Security (IP Security) is a security protocol that serves to secure information in the event of an exchange on the internet. It happens if there is a connection between private IP and public IP. This protocol will exchange packets on the IP layer safely. It provides two types of encryption options, transport, and tunnel. Transport mode will encrypt the data section without changing the packet header. The algorithm used to encrypt data is a symmetric cryptography algorithm. This protocol authenticates and encrypts every packet from a data transmission session. Also, it can generate keys between the sender and the recipient at the first time it is activated and can negotiate the cryptographic keys that will be used during the session. IP Security is an end-to-end cryptosystem that works at the internet layer of the Internet Protocol Suite. The protocol serves to protect the data flow in host-to-host, network-to-network, and network-to-host as well.

Development of network technology, especially Internet technology is now so large that almost any facilities for information requires an internet connection, the more available and easy communication allows the cyber-attacks against the objects connected to the Internet, to minimize cyber-attacks need to be overcome by providing defense in the form of network security, especially in the vital objects such as government agencies, hospitals and banks as well as many other objects also necessary secured, one of the way for protected network were using firewall.

Making a decision is a crucial step in a management, the decision will have a significant impact on the policies to be taken by the top management, SMART (Simple Multi-Attribute Rating Technique) is the method used for making a decision with the completion of many criteria with results pretty good, this study provides an overview of how the methods SMART (Simple Multi-Attribute Rating Technique) works with many criteria.

There are many data security techniques like a cryptography, there are many algorithm like a MMB (Modular Multiplication Block Cipher) and Playfair Cipher. MMB operates using 128-bit plaintext, but it also uses 32-bit subblock MMB text (x0, x1, x2, x3) and 32-bit key subblock (k0, k1, k2, k3) and then the fundamental of this algorithm is determined by a multiplication modulo operation 2 32-1. Different from MMB, playfair cipher is a diagram substitution cipher which takes two letter from message and replace with two another pair letter, this paper combines playfair cipher as a key substitution and messages in plaintext to be encrypted with algorithms MMB, this combination is expected to increase the security level of messages.

There are many data security techniques like a cryptography, there are many algorithm like a MMB (Modular Multiplication Block Cipher) and Playfair Cipher. MMB operates using 128-bit plaintext, but it also uses 32-bit subblock MMB text (x0, x1, x2, x3) and 32-bit key subblock (k0, k1, k2, k3) and then the fundamental of this algorithm is determined by a multiplication modulo operation 2 32-1. Different from MMB, playfair cipher is a diagram substitution cipher which takes two letter from message and replace with two another pair letter, this paper combines playfair cipher as a key substitution and messages in plaintext to be encrypted with algorithms MMB, this combination is expected to increase the security level of messages.

Digital image processing is a computational process that is widely used today starting from editing photos or also the manipulation of the picture, one form of image processing is edge detection, edge detection in images is one technique that can be used to mark parts into detail of the picture, either a blurred image due to error or the effect of the image acquisition process, in this study using the Frei-Chen algorithm to perform edge detection image in order to know the borders of the picture.

Data communication performed at any time does not always go well, sometimes also happens that his name error when transmitting data. The detection and correction of errors in data transmission requires special algorithms in this study using the algorithm Hamming Code, the use of this algorithm due to ease in the detection and correction of bit damaged and is expected by this research easier for other researchers to develop algorithms Hamming Code for a variety of purposes in data transmission.