16-09-2016, 02:38 PM
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INTRODUCTION
1.1 MOTIVATION
The internet plays an important role in day-to-day life. The people can transfer important data through the internet such as Email, banking transaction and online purchase. In order to get secured transaction, networksecurity is essential. Network security is mostly achieved through the use of cryptography. Cryptography refers to theart and science of transforming the message to make them secure and immune to attacks. Different algorithms and protocols are used to protect the data.
Blowfishwas designed in 1993 by Bruce Schneideras a fast, free alternative to existing encryption algorithms. Blowfishis a symmetric block cipher that can be effectively used for encryption and safeguarding of data. It takes a variable-length key from 32 bits to 448 bits, making it ideal for securing data.It is significantly faster than most encryption algorithms and can encrypt data on 32-bit microprocessors at a rate of one byte every 26 clock cycles.
The algorithm is compact and can run in less than 5K of memory.The elementary operators of Blowfish algorithm include table lookup, addition and XOR.The cipher is 16 round Feistel network which utilizes a structure that makes encryption and decryption very similar through use of S-boxes and a P-arrayachieve Linear mixing.The algorithm is hereby placed in the public domain and can be freely used by anyone.It is suitable for applications where the key does not change often like a communications link or an automatic file encryptor.
CHAPTER 2
LITERATURE SURVEY
1.Jude Angelo Ambrose et al(2008) has explained theside channel attack based upon the analysis of power traces is an effective way of obtaining the encryption key from secure processors. Power traces can be used to detect bit flips which betray the secure key. Balancing the bit flips with opposite bit flipshas been analyzed, by the use of opposite logic. A multiprocessor balancing technique to prevent the power analysis attacks in the Blowfish cryptographic program has been adopted. A dual processor chip is used where the second processor is affixed for balancing only when the encryption program in Blowfish is detected using a signature by the first processor. Since balancing is performed only when necessary, the performance of the system is significantly improved in comparison to the other balancing methods.It is adapted for most of mobile systems today due to the simplicity in its operation and making it faster in terms of both encryption and decryption.
2.Abomhara et al(2010)has summarizedthe encryption methodologies are needed that can protect digital video from attacks during transmission. Due to the huge size of digital videos, they are usually transmitted in compressed formats such as MPEG or H.264.The encryption algorithms for digital video are usually working in the compressed domain. Several encryption algorithms to secure video streaming have been analyzed. Most of them tried to optimize the encryption process can be varies with encryption speed, and display process.
Encryption algorithm for secure video streams has been evaluated with respect to three metrics namely security level, encryption speed, and encrypted MPEG stream size.Naïve Algorithm and Video Encryption Algorithm (VEA) are the most secure algorithms, where Zigzag Permutation Algorithm has serious security flaws and cannot withhold the known plaintext attacknor the cipher text only attack. The two different types of the encryption methods (Symmetric key encryption and Asymmetric key encryption) were evaluated with respect to their security level and encryption speed.Zig-Zag Permutation Algorithm significantly increase the stream size during the compression purpose of MPEG encoding. It was found that, with respect to the encryption speed, Pure Permutation algorithm and Zigzag permutation algorithm are very fast, and Naive Algorithm is very slow due to applying DES on whole MPEG stream
3.MitaliVijayKumar and Arvind Sharma(2014)has analysedthe encryptiontechniques well to promote the performance of the encryption methods and also to ensure the security proceedings. The performance evaluation of selected symmetric algorithms has been done. The selected algorithms are AES, 3DES, Blowfish and DES. The simulation results shows that theBlowfish has better performance than other algorithms.It was found that AES,3DES has least efficient of all the cryptographic algorithms.
4.MonikaAgrawal and PradeepMishra(2012) has explained many cryptographic algorithms and implemented to provide security to the user that his/her message would remain safe at the time of communication over the web. But now a days hacking has become a common practice in society which made such cryptographic algorithms no longer safe. A detailed study of the most popular symmetric key encryption algorithm that is Blowfish and its advantages were discussed. Based on the benefits of Blowfish algorithm a new approach of modified Blowfishalgorithm were implemented to achieve better results in terms of parameters such as Encryption time, Decryption time and Throughput. The striking feature of modified blowfish encryption algorithm is that for the same input plaintext the cipher text generated at each time will be different. This is because every time a new random number gets generated and a result gives difference in the application of F function over each round.
The advantage of different cipher text generated for the same input increase the security aspect of blowfish algorithm.It was observed that Symmetric Encryption Algorithm runs faster as compared to Asymmetric key algorithms. The memory requirement of Symmetric algorithm is lesser as compared to asymmetric
5.Ayushkesarwani and MilindMathur (2013)has described the comparison in performance of six most useful algorithms DES,3DES,AES,RC2,RC6 and BLOWFISH. Performance of different algorithms is different according to data loads.Depending on the algorithm, and length of the key, the strength of encryption can be measured.There is no significant difference when the results are displayed either in hexadecimal base encoding or in base 64 encoding. In the case of changing packet size, it was found that Blowfish has better performance than other common encryption algorithms used. In the case of changing key size – it was established that higher key size leads to clear change in the battery and time consumption.
It was noticed that Blowfish shows the better performance in throughput and power consumption. The RC6 requires less time than all algorithms.AES has an advantage over other 3DES,DES,RC2.It was found that RC2 still has low performance Compared to other algorithm.AES encryption is fast and flexible. Brute force attack is the only effective attack known against this algorithm
6.Karamjeetsingh andPiasingh(2013)has describedabout encryption and decryption of images using a secret-key block cipher of 64-bits.Blowfish is designed to increase the security and to improve performance. It uses a variable key size up to 448 bits. It employs Feistelnetwork which iterates simple function 16 times. The blowfish algorithm is safe against unauthorized attack and runs faster than the popular existing algorithms.
The algorithm is designed and realized using MATLAB,Both colour and black & white image of any size saved in tagged image file format (TIF), Bit map (bmp), Portable network graphics (PNG), Joint Photographic Experts group (jpg) can be encrypted & decrypted using blowfish algorithm. Histogram of encrypted image is less dynamic and significantly different from the respective histograms of the original image. Blowfish cannot be broken until an attacker tries 28r+1 combinations where r is the number of rounds. If the number of rounds is increased then the blowfish algorithm becomes stronger. Blowfish has not known security weak points so it can be considered as an excellent standard encryption algorithm.
7.PratapChnadraMandal(2012)hasprovided a fair comparison between the most common and used symmetrickey algorithm. The comparison has been made on the basis of these parameters such as rounds, block size, key size, and encryption or decryption time,CPU process time in the form of throughput and power consumption.Itwas found that AES is faster and more efficient than other encryption algorithms. When the transmission of data is considered there is insignificant difference in performance of different symmetric key schemes. During data transfer it was advised to use AES scheme in case the encrypted data is stored at the other end.The performance was compared by encrypting input files of varying sizes and contents.RSA takes more memory than AES and DES.The output byte is calculated by the size of output byte of each algorithm. It was established that the level of output byte is equal for AES and DES, but RSA algorithm produces low level of output byte.
8. Christina L and Joe IrudayarajVS (2014)has proposeda new approach to generate a random number using image. Read the picture by pixel, select the specific location randomly by pick any two colours. Apply XOR between two selected colours then specify the length of the key. Thekey is used to encrypt or decrypt the plaintext. They key generation method is applied into the Blowfish algorithm. It was suggested that this type of key generation is suitable for short keys in symmetric system. It was found that a new hybrid technique from the combination of cryptography and stenography for transmitting the message in a highly secured manner was established. The plaintext is encrypted using Blowfish algorithm and the resulted cipher text is embedded into an audio file using discrete wavelet transform. It wasrecognised that this method is efficient method for hiding text in audio files such that data can reach the destination in a safe manner without any modification.
9. Muhammad et al(2009)has reviewed a high performance and highly optimized hardware realization of Rijndael AES Algorithm has been designed and implemented on Xilinx Virtex-5 XC5VLX50 FPGA device. The design has been coded using modular approach by using VHDL Language. The performance of the design is evaluated based on throughput and area. It was found that the design utilizes a speed of 339.087 MHz, which translates to throughput of 4.34 Gbps using an area of 399 slices of a Virtex-5 FPGA.FPGAs are considered one of the important hardware platforms and integral part for the cryptographic algorithms implementation.FPGAs offer much easier and reasonably cheap solution for the implementation of cryptographic algorithm.Custom architecture in reconfigurablehardware was designed to speed up the performance and flexibility of Rijndael algorithm implementation.
CHAPTER 3
CRYPTOGRAPHY
3.1INTRODUCTION
Cryptography is the science of using mathematics to encrypt and decrypt data. Cryptography enables you to store sensitive information or transmit it across insecure networks (like the Internet) so that it cannot be read by anyone except the intended recipient. Cryptanalysis is the science of analysing and breaking secure communication. Cryptanalysts are also called attackers. Due to the great security advantages of cryptography it is widely used today.
The various goals of cryptography are Confidentiality, Authentication, Integrity, Non Repudiation and Access Control.Only the authorized parties will be able to access the information.Cryptography is quite interesting because It poses lots of challenging problems with impact on real life and It covers a broad range of mathematics and computer science.
3.2 BASIC TERMS USED IN CRYPTOGRAPHY
3.2.1 Plain Text
The original message that we wish to communicate with the others is defined as Plain Text. In cryptography the actual data that has to be send to the other is referred as Plain Text. For example, Alice is a person wishes to send “Congratulation” message to the person Duke. Here “Congratulation” is a plain text message.
3.2.2 Cipher Text
The message which has been converted by the encryption algorithm is called cipher text. In Cryptography the original message is transformed into non readable message.
3.2.3 Encryption
A process of converting plain text into cipher text is called as Encryption. Cryptography uses the encryption algorithm and a key to send confidential data through an insecure channel.
3.2.4Decryption
A reverse process of encryption is called decryption. It is a process of converting cipher text into plain text. Decryption requires decryption algorithm and a key.
3.3 ENCRYPTION AND DECRYPTION
Data that can be read and understood without any special measures is called plaintext or clear text. The method of disguising plaintext in such a way as to hide its substance is called encryption as shown in the Fig 3.1.Encrypting plaintext results in unreadable gibberish called ciphertext. The useof encryption is to ensure that information is hidden from anyone for whom it is not intended, even those who can see the encrypted data. The process of reversing ciphertext to its original plaintext is called decryption. Encryption takes place at the sender end and Decryption takes place at the receiver end. The input to the encryption process is plain text and that of decryption process is cipher text. First the plaintext is passed through the encryption algorithm which encrypts the plaintext using a key and then, the produced cipher text is transmitted.
At the end of decryption, the input cipher text is passed through the decryption algorithm which decrypts the cipher text using the same key as that of encryption. Finally we get the original plaintext message.
3.4MODES OF ENCRYPTION/DECRYPTION
Secret key cryptography schemes are generally categorized as being either stream ciphers or block cipher. Stream ciphers operate on a single bit at a time and implement some form of feedback mechanism so that the key is constantly changing. A block cipherwhich encrypts one block of data at a time using the same key on each block. Block ciphers can operate in one of several modes.
3.4.1Electronic Codebook (ECB)
This mode is the simplest and most obvious application. The secret key is used to encrypt the plaintext block to form a cipher text block. Two identical plaintext blocks, then, will always generate the same cipher text block. Although, this is the most common mode of block ciphers, it is vulnerable to a variety of brute force attacks.In this mode data is divided into 64-bit blocks and each block is encrypted one at a time. Separate encryptions with different blocks are totally independent of each other. It means that if data is transmitted over a network or phone line, transmission errors will only affect the block containing the error.
INTRODUCTION
1.1 MOTIVATION
The internet plays an important role in day-to-day life. The people can transfer important data through the internet such as Email, banking transaction and online purchase. In order to get secured transaction, networksecurity is essential. Network security is mostly achieved through the use of cryptography. Cryptography refers to theart and science of transforming the message to make them secure and immune to attacks. Different algorithms and protocols are used to protect the data.
Blowfishwas designed in 1993 by Bruce Schneideras a fast, free alternative to existing encryption algorithms. Blowfishis a symmetric block cipher that can be effectively used for encryption and safeguarding of data. It takes a variable-length key from 32 bits to 448 bits, making it ideal for securing data.It is significantly faster than most encryption algorithms and can encrypt data on 32-bit microprocessors at a rate of one byte every 26 clock cycles.
The algorithm is compact and can run in less than 5K of memory.The elementary operators of Blowfish algorithm include table lookup, addition and XOR.The cipher is 16 round Feistel network which utilizes a structure that makes encryption and decryption very similar through use of S-boxes and a P-arrayachieve Linear mixing.The algorithm is hereby placed in the public domain and can be freely used by anyone.It is suitable for applications where the key does not change often like a communications link or an automatic file encryptor.
CHAPTER 2
LITERATURE SURVEY
1.Jude Angelo Ambrose et al(2008) has explained theside channel attack based upon the analysis of power traces is an effective way of obtaining the encryption key from secure processors. Power traces can be used to detect bit flips which betray the secure key. Balancing the bit flips with opposite bit flipshas been analyzed, by the use of opposite logic. A multiprocessor balancing technique to prevent the power analysis attacks in the Blowfish cryptographic program has been adopted. A dual processor chip is used where the second processor is affixed for balancing only when the encryption program in Blowfish is detected using a signature by the first processor. Since balancing is performed only when necessary, the performance of the system is significantly improved in comparison to the other balancing methods.It is adapted for most of mobile systems today due to the simplicity in its operation and making it faster in terms of both encryption and decryption.
2.Abomhara et al(2010)has summarizedthe encryption methodologies are needed that can protect digital video from attacks during transmission. Due to the huge size of digital videos, they are usually transmitted in compressed formats such as MPEG or H.264.The encryption algorithms for digital video are usually working in the compressed domain. Several encryption algorithms to secure video streaming have been analyzed. Most of them tried to optimize the encryption process can be varies with encryption speed, and display process.
Encryption algorithm for secure video streams has been evaluated with respect to three metrics namely security level, encryption speed, and encrypted MPEG stream size.Naïve Algorithm and Video Encryption Algorithm (VEA) are the most secure algorithms, where Zigzag Permutation Algorithm has serious security flaws and cannot withhold the known plaintext attacknor the cipher text only attack. The two different types of the encryption methods (Symmetric key encryption and Asymmetric key encryption) were evaluated with respect to their security level and encryption speed.Zig-Zag Permutation Algorithm significantly increase the stream size during the compression purpose of MPEG encoding. It was found that, with respect to the encryption speed, Pure Permutation algorithm and Zigzag permutation algorithm are very fast, and Naive Algorithm is very slow due to applying DES on whole MPEG stream
3.MitaliVijayKumar and Arvind Sharma(2014)has analysedthe encryptiontechniques well to promote the performance of the encryption methods and also to ensure the security proceedings. The performance evaluation of selected symmetric algorithms has been done. The selected algorithms are AES, 3DES, Blowfish and DES. The simulation results shows that theBlowfish has better performance than other algorithms.It was found that AES,3DES has least efficient of all the cryptographic algorithms.
4.MonikaAgrawal and PradeepMishra(2012) has explained many cryptographic algorithms and implemented to provide security to the user that his/her message would remain safe at the time of communication over the web. But now a days hacking has become a common practice in society which made such cryptographic algorithms no longer safe. A detailed study of the most popular symmetric key encryption algorithm that is Blowfish and its advantages were discussed. Based on the benefits of Blowfish algorithm a new approach of modified Blowfishalgorithm were implemented to achieve better results in terms of parameters such as Encryption time, Decryption time and Throughput. The striking feature of modified blowfish encryption algorithm is that for the same input plaintext the cipher text generated at each time will be different. This is because every time a new random number gets generated and a result gives difference in the application of F function over each round.
The advantage of different cipher text generated for the same input increase the security aspect of blowfish algorithm.It was observed that Symmetric Encryption Algorithm runs faster as compared to Asymmetric key algorithms. The memory requirement of Symmetric algorithm is lesser as compared to asymmetric
5.Ayushkesarwani and MilindMathur (2013)has described the comparison in performance of six most useful algorithms DES,3DES,AES,RC2,RC6 and BLOWFISH. Performance of different algorithms is different according to data loads.Depending on the algorithm, and length of the key, the strength of encryption can be measured.There is no significant difference when the results are displayed either in hexadecimal base encoding or in base 64 encoding. In the case of changing packet size, it was found that Blowfish has better performance than other common encryption algorithms used. In the case of changing key size – it was established that higher key size leads to clear change in the battery and time consumption.
It was noticed that Blowfish shows the better performance in throughput and power consumption. The RC6 requires less time than all algorithms.AES has an advantage over other 3DES,DES,RC2.It was found that RC2 still has low performance Compared to other algorithm.AES encryption is fast and flexible. Brute force attack is the only effective attack known against this algorithm
6.Karamjeetsingh andPiasingh(2013)has describedabout encryption and decryption of images using a secret-key block cipher of 64-bits.Blowfish is designed to increase the security and to improve performance. It uses a variable key size up to 448 bits. It employs Feistelnetwork which iterates simple function 16 times. The blowfish algorithm is safe against unauthorized attack and runs faster than the popular existing algorithms.
The algorithm is designed and realized using MATLAB,Both colour and black & white image of any size saved in tagged image file format (TIF), Bit map (bmp), Portable network graphics (PNG), Joint Photographic Experts group (jpg) can be encrypted & decrypted using blowfish algorithm. Histogram of encrypted image is less dynamic and significantly different from the respective histograms of the original image. Blowfish cannot be broken until an attacker tries 28r+1 combinations where r is the number of rounds. If the number of rounds is increased then the blowfish algorithm becomes stronger. Blowfish has not known security weak points so it can be considered as an excellent standard encryption algorithm.
7.PratapChnadraMandal(2012)hasprovided a fair comparison between the most common and used symmetrickey algorithm. The comparison has been made on the basis of these parameters such as rounds, block size, key size, and encryption or decryption time,CPU process time in the form of throughput and power consumption.Itwas found that AES is faster and more efficient than other encryption algorithms. When the transmission of data is considered there is insignificant difference in performance of different symmetric key schemes. During data transfer it was advised to use AES scheme in case the encrypted data is stored at the other end.The performance was compared by encrypting input files of varying sizes and contents.RSA takes more memory than AES and DES.The output byte is calculated by the size of output byte of each algorithm. It was established that the level of output byte is equal for AES and DES, but RSA algorithm produces low level of output byte.
8. Christina L and Joe IrudayarajVS (2014)has proposeda new approach to generate a random number using image. Read the picture by pixel, select the specific location randomly by pick any two colours. Apply XOR between two selected colours then specify the length of the key. Thekey is used to encrypt or decrypt the plaintext. They key generation method is applied into the Blowfish algorithm. It was suggested that this type of key generation is suitable for short keys in symmetric system. It was found that a new hybrid technique from the combination of cryptography and stenography for transmitting the message in a highly secured manner was established. The plaintext is encrypted using Blowfish algorithm and the resulted cipher text is embedded into an audio file using discrete wavelet transform. It wasrecognised that this method is efficient method for hiding text in audio files such that data can reach the destination in a safe manner without any modification.
9. Muhammad et al(2009)has reviewed a high performance and highly optimized hardware realization of Rijndael AES Algorithm has been designed and implemented on Xilinx Virtex-5 XC5VLX50 FPGA device. The design has been coded using modular approach by using VHDL Language. The performance of the design is evaluated based on throughput and area. It was found that the design utilizes a speed of 339.087 MHz, which translates to throughput of 4.34 Gbps using an area of 399 slices of a Virtex-5 FPGA.FPGAs are considered one of the important hardware platforms and integral part for the cryptographic algorithms implementation.FPGAs offer much easier and reasonably cheap solution for the implementation of cryptographic algorithm.Custom architecture in reconfigurablehardware was designed to speed up the performance and flexibility of Rijndael algorithm implementation.
CHAPTER 3
CRYPTOGRAPHY
3.1INTRODUCTION
Cryptography is the science of using mathematics to encrypt and decrypt data. Cryptography enables you to store sensitive information or transmit it across insecure networks (like the Internet) so that it cannot be read by anyone except the intended recipient. Cryptanalysis is the science of analysing and breaking secure communication. Cryptanalysts are also called attackers. Due to the great security advantages of cryptography it is widely used today.
The various goals of cryptography are Confidentiality, Authentication, Integrity, Non Repudiation and Access Control.Only the authorized parties will be able to access the information.Cryptography is quite interesting because It poses lots of challenging problems with impact on real life and It covers a broad range of mathematics and computer science.
3.2 BASIC TERMS USED IN CRYPTOGRAPHY
3.2.1 Plain Text
The original message that we wish to communicate with the others is defined as Plain Text. In cryptography the actual data that has to be send to the other is referred as Plain Text. For example, Alice is a person wishes to send “Congratulation” message to the person Duke. Here “Congratulation” is a plain text message.
3.2.2 Cipher Text
The message which has been converted by the encryption algorithm is called cipher text. In Cryptography the original message is transformed into non readable message.
3.2.3 Encryption
A process of converting plain text into cipher text is called as Encryption. Cryptography uses the encryption algorithm and a key to send confidential data through an insecure channel.
3.2.4Decryption
A reverse process of encryption is called decryption. It is a process of converting cipher text into plain text. Decryption requires decryption algorithm and a key.
3.3 ENCRYPTION AND DECRYPTION
Data that can be read and understood without any special measures is called plaintext or clear text. The method of disguising plaintext in such a way as to hide its substance is called encryption as shown in the Fig 3.1.Encrypting plaintext results in unreadable gibberish called ciphertext. The useof encryption is to ensure that information is hidden from anyone for whom it is not intended, even those who can see the encrypted data. The process of reversing ciphertext to its original plaintext is called decryption. Encryption takes place at the sender end and Decryption takes place at the receiver end. The input to the encryption process is plain text and that of decryption process is cipher text. First the plaintext is passed through the encryption algorithm which encrypts the plaintext using a key and then, the produced cipher text is transmitted.
At the end of decryption, the input cipher text is passed through the decryption algorithm which decrypts the cipher text using the same key as that of encryption. Finally we get the original plaintext message.
3.4MODES OF ENCRYPTION/DECRYPTION
Secret key cryptography schemes are generally categorized as being either stream ciphers or block cipher. Stream ciphers operate on a single bit at a time and implement some form of feedback mechanism so that the key is constantly changing. A block cipherwhich encrypts one block of data at a time using the same key on each block. Block ciphers can operate in one of several modes.
3.4.1Electronic Codebook (ECB)
This mode is the simplest and most obvious application. The secret key is used to encrypt the plaintext block to form a cipher text block. Two identical plaintext blocks, then, will always generate the same cipher text block. Although, this is the most common mode of block ciphers, it is vulnerable to a variety of brute force attacks.In this mode data is divided into 64-bit blocks and each block is encrypted one at a time. Separate encryptions with different blocks are totally independent of each other. It means that if data is transmitted over a network or phone line, transmission errors will only affect the block containing the error.