The diplomatic correspondence between Heinrich Friedrich Diez, Prussian chargé d’affaires at the Sublime Porte in Constantinople, and Christian Konrad Wilhelm Dohm: its decipherment and historical relevance

A new hybrid security algorithm is presented for RSA cryptosystem named as Hybrid RSA. The system works on the concept of using two different keys- a private and a public for decryption and encryption processes. The value of public key (P) and private key (Q) depends on value of M, where M is the product of four prime numbers which increases the factorizing of variable M. moreover, the computation of P and Q involves computation of some more factors which makes it complex. This states that the variable x or M is transferred during encryption and decryption process, where x represents the multiplication of two prime numbers A and B. thus, it provides more secure path for encryption and decryption process. The proposed system is compared with the RSA and enhanced RSA (ERSA) algorithms to measure the key generation time, encryption and decryption time which is proved to be more efficient than RSA and ERSA.

This research compares the performance of different data encryption techniques using cryptographic evaluation metrics. Encryption in cryptography involves encoding data to prevent unauthorized access, transforming plaintext into ciphertext. Many encryption methods exist, but their effectiveness varies and has not been thoroughly assessed. Previous studies have focused on evaluating public-key cryptography, particularly RSA and ECC algorithms, across various parameters. Findings suggest risks associated with smaller key sizes. Therefore, this study evaluates the performance of RSA, DSA, PGP, and ECC algorithms. Ten JPEG medical images (ranging from 321kb to 675kb) and two video files (2.23 mb in AVI and MP4 formats) were obtained from www.pexel.com for testing purposes. The images were converted to grayscale and the video frames were converted to ASCII values to accelerate encryption and decryption processes. Python 3.11 was used to implement encryption algorithms, and their performance was evaluated based on encryption time, decryption time, peak signal-to-noise ratio (PSNR), and key length. The RSA, DSA, PGP, and ECC gave 0.0065s, 0.0754s, inf (dB), and 2048 bits; 0.0486s, 0.0391s, inf (dB), and 1024 bits; 0.1986s, 0.2779s, inf (dB), and 2048 bits; 0.0125s, 0.0031s, inf (dB), and 256 bits for encryption time, decryption time, peak signal-to-noise ratio (PSNR) and key length respectively for medical images. The corresponding values for video avi data were 0.0129s, 0.0609s, inf (dB), and 2048 bits; 0.1269s, 0.1339s, inf (dB), and 1024 bits; 0.2954s, 0.2428s, inf (dB), and 2048 bits; 0.0169, 0.0109s, inf (dB), and 256 bits respectively. Also, the corresponding values for video mp4 data were 0.0159s, 0.0919s, inf (dB), and 2048 bits; 0.1539s, 0.1399s, inf (dB), and 1024 bits; 0.3738s, 0.2518s, inf (dB), and 2048 bits; 0.0721, 0.0090s, inf (dB), and 256 bits respectively. The study found that ECC outperforms RSA, DSA, and PGP in operational efficiency and security. ECC demonstrates shorter decryption times and stronger key lengths, with all algorithms achieving infinite peak signal-to-noise ratios, maintaining data quality throughout encryption and decryption. While RSA has the shortest encryption time, ECC excels across other metrics. The study recommends adopting ECC for shorter encryption times, faster decryption times, higher peak-to-noise ratios, and longer keys, highlighting its overall superiority. Keywords: Cryptography, Algorithm, Asymmetric, Rivest Shamir Adleman (RSA), Digital Signature Algorithm (DSA), Pretty Good Privacy (PGP), Elliptic Curve Cryptography (ECC) Oluwasanya, E.O., Olabiyisi, S.O. & Omotosho, O.I. (2024): Performance Comparison of Some Asymmetric Data Encryption Algorithms. Journal of Advances in Mathematical & Computational Science. Vol. 12, No. 3. Pp 27-36 Available online at www.isteams.net/mathematics-computationaljournal. dx.doi.org/10.22624/AIMS/MATHS/V12N3P2

Cloud computing became popular due to its elasticity, unparalleled resource availability on demand and almost zero downtime. Looking into the advantages of cloud computing, industries are moving their IT infrastructure from on-premises to cloud infrastructure irrespective of their size, business area, and customer orientation. Major challenge for cloud service providers is to provide guaranteed data security without compromising the performance of data encryption/decryption, both at rest and during intransit. Many symmetric and asymmetric algorithms already exist with their own pros and cons. The robustness of the algorithm depends upon the key size and the complexity of the algorithm used in encryption and decryption process. In this paper we derived a hybrid algorithm to make the encryption process robust without degrading performance. This proposed algorithm makes the encryption and decryption process simple but harden the sub-keys generation process by taking larger dynamic key length and complex processing steps. We refer AES for robustness during sub-key generation process and refers blowfish for encryption and decryption process to make it simpler and fast. As per the experimental result, the proposed hybrid algorithm performs better than AES in terms of encryption/ decryption time and more robust than Blowfish and AES.

This study aims to maintain the confidentiality of audio files sent using a combination of the Playfair cipher and Vigenere cipher methods. In this research, the object of research is an audio file with the extension wave or *.wav. This research requires several stages, including Audio Data Analysis, Determination of System Architecture, Implementation, Testing, and Results Analysis. The results of this study indicate that in the Vigenere Cipher 256 Encryption in audio wave files, the audio messages conveyed sound unclear or have no meaning. From the 6 trial datasets based on analysis of MAE and PSNR, the average value of the encryption process at PSNR was 28.345, and MAE was 97.0625. The average value of the decryption process on PSNR and MAE is 0.0, indicating that the decryption process is successful. The speed of the encryption and decryption process is affected by the audio file's size, which means that the larger the file size, the longer the encryption and decryption time.

In the rapid evolving digital landscape, the imperative to ensure data security has never been more crucial. This paper addresses the pressing challenges in data security by introducing a file encryption management system, leveraging a modified advanced encryption standard (AES) algorithm with reduced round iterations and bit permutation. This system aims to comprehensively secure various file types, providing a dependable solution for file exchange. Our findings reveal substantial improvements in both encryption and decryption processes using the reduced-round permutation-based AES (RRPBA). The adapted algorithm demonstrates a significant 38.8% acceleration in encryption time and a remarkable 44.86% improvement in decryption time, positioning it as a pivotal component for efficient file operations within the management system. Moreover, the throughput assessments showcase a remarkable 33.73% improvement in encryption and 23.72% in decryption, outperforming the original AES, emphasizing the algorithm's superior computational effectiveness, signaling positive implications for future high-performance applications. In conclusion, the study not only addresses critical security challenges but also presents a viable solution with tangible speed advantages for file encryption and decryption processes within digital file management systems.

The rapid The main problem in the misuse of data used in crime is the result of a lack of file security. This study proposes a data security method to protect document files using the Advanced Encryption Standard (AES) algorithm combined with the Vigenere Cipher. This research carried out 2 processes, namely the encryption process and the decryption process. The encryption process will be carried out by the AES algorithm and then encrypted again with the Vigenere Cipher algorithm. The experiments show that the proposed method can encrypt files properly, where there are changes in the value of the document file and the encrypted file cannot be opened and the description results do not cause changes to the original file. The results of this study are that the system is able to work properly so as to produce file encryption and decryption using the AES method combined with the Vigenere Cipher. In document files, the largest difference in encryption and decryption time is 8 seconds, while in image files the difference in encryption and decryption time is 17 seconds. This longest time difference is generated by large files.

The advancements made in Internet of Things (IoT) is projected to alter the functioning of healthcare industry in addition to increased penetration of different applications. However, data security and private are challenging tasks to accomplish in IoT and necessary measures to be taken to ensure secure operation. With this background, the current paper proposes a novel lightweight cryptography method for enhance the security in IoT. The proposed encryption algorithm is a blend of Cross Correlation Coefficient (CCC) and Black Widow Optimization (BWO) algorithm. In the presented encryption technique, CCC operation is utilized to optimize the encryption process of cryptography method. The projected encryption algorithm works in line with encryption and decryption processes. Optimal key selection is performed with the help of Artificial Intelligence (AI) tool named BWO algorithm. With the combination of AI technique and CCC operation, optimal security operation is improved in IoT. Using different sets of images collected from databases, the projected technique was validated in MATLAB on the basis of few performance metrics such as encryption time, decryption time, Peak Signal to Noise Ratio (PSNR), CC, Error, encryption time and decryption time. The results were compared with existing methods such as Elliptical Curve cryptography (ECC) and Rivest-Shamir-Adleman (RSA) and the supremacy of the projected method is established.

Cryptographic techniques are crucial in ensuring the security of Wireless Sensor Networks data to limit the effect of such offensive operations. As a consequence, many cryptographic techniques are used to assure network security. Cryptography makes use of two techniques: symmetric-key and asymmetric-key cryptography. However, specific concerns remain. In this paper, a hybrid security algorithm is proposed. It provides both high security and fast encryption and decryption processes by using symmetric-key and asymmetric-key techniques. In addition, it provides three cryptographic primitives: confidentiality, authentication, and integrity. The concept is to encrypt using Blowfish, Rivest Cipher 4, and the Advanced Encryption Standard. Message Digest 5 is used for integrity, and Elliptic Curve Diffie Hellman is used for authentication. Two computers and a Raspberry Pi test the proposed algorithm's performance. The proposed algorithm exceeds numerous current algorithms in ciphertext size, encryption time, decryption time, and throughput. Using a Raspberry Pi 4 Model B and a plaintext size of 184,162 bytes, the proposed algorithm achieved a 37% reduction in ciphertext size, a 90.5% reduction in encryption time, a 62.7% reduction in decryption time, and a 1052% increase in throughput compared to previously published works.

In recent days chaos based image encryption is going through under research and implementation. Some chaos based algorithms are working well and resists many type of crypto analysis attacks, but it takes lot of time for encryption and decryption. Some of chaos based algorithms are very fast but their strength to resist attack is questionable. So these have motivated us to design a crypto system which will take less amount of time for encryption and decryption and it should resist all type of crypto analysis attacks. In this paper we have developed an advanced image encryption scheme by using block based randomization and chaos system. Here we discuss a block based transformation algorithm in which image is divided in to number of blocks. Then these blocks are transformed before going through a chaos based encryption process. At the receiver side after decryption, these blocks are re- transformed in to their original position. The main advantage of this approach is that it reproduces the original image with no loss of information during the encryption and decryption process in a reasonable amount of time, and due to sensitive chaos system becomes it more secure and reliable over the network.

Along with the development of technology, communication can be done in various ways, one of which is digital messages. But often the messages sent do not reach their destination and are obtained by irresponsible parties. This happens because of the lack of security in the file. For this reason, security is needed so that messages cannot be stolen or seen by other parties. There are various ways to secure messages, including Steganography and Cryptography techniques. This study uses a combination of the Least Significant Bit method and the Blowfish algorithm to secure secret messages in audio files. This research will measure encryption and decryption time, analysis of message file size changes after encryption and decryption, and PSNR value of audio files. The result of encryption using blowfish is a change in the size of the message file caused by the size of the message file is less than the block cipher size, so additional bytes are given so that the message size matches the block cipher size. The speed of the encryption and decryption process using the blowfish algorithm results in an average time for encryption of 547.98ms while the average time for decryption is 538.19ms. The longest time for the encryption process is 557.30ms and the fastest is 534.50ms, while the longest time for the decryption process is 548.74ms and the fastest is 531.46ms. Hiding messages in audio files using LSB produces PSNR values above 30dB.

This paper presents an optical image encryption system based on grating diffraction imaging and interference superposition principle. When the encryption is performed, an image is encrypted into several ciphertexts by vector superposition, and a random phase is added to each ciphertext to prevent the generation of contours in decryption. During the decryption process, the nature of the grating diffraction in the 4f system would be used, and then, all the ciphertexts would be superimposed on the same position at the output plane, so that an accurate decrypted image can be obtained. Since the random phase is especially processed during encryption, only the complete information of the ciphertexts needs to be known at the time of decryption, and the random phase information is not needed to recover the image. If we do not have enough information of the ciphertexts, we cannot recover the correct decrypted image. Computer simulations prove its possibility.

Providing security for transmitted data through the e-commerce environment requires using a fast and high secure encryption algorithm. Balancing between the speed and the security degree is a problem that many of the encryption algorithms suffer from. Increasing the security degree requires increasing the level of complexity which results in increasing encryption time. On the other hand, increasing the algorithm speed may reduce the complexity degree which affects the security level. This paper aims to design an encryption algorithm that balances time and complexity (speed and security). This is done by suggesting a security environment that depends on creating and providing an agent software to be settled into each customer device that manages the purchase and security process without customer interference. The suggested encryption algorithm is applied within this environment. Several modifications are performed on the AES encryption algorithm. The AES was chosen due to its performance (security and speed), which makes it suitable for encrypting transmitted data over the Internet. These modifications involve adding preprocessing steps (padding and zigzag), eliminating Sub Byte step, and reducing the number of rounds. The experimental results showed that the suggested algorithm provides more security and speed in the encryption and decryption process. The randomness degree has increased by 29.5%. The efficiency is increased because the encryption and decryption times are reduced, as is the CPU usage. The throughput for the suggested algorithm is increased by 10% for the encryption process and is increased by 9.3% for the decryption process.

Purpose There are various system techniques or models which are used for access control by performing cryptographic operations and characterizing to provide an efficient cloud and in Internet of Things (IoT) access control. Particularly in cloud computing environment, there is a large-scale distribution of these traditional symmetric cryptographic techniques. These symmetric cryptographic techniques use the same key for encryption and decryption processes. However, during the execution of these phases, they are under the problems of key distribution and management. The purpose of this study is to provide efficient key management and key distribution in cloud computing environment. Design/methodology/approach This paper uses the Cipher text-Policy Attribute-Based Encryption (CP-ABE) technique with proper access control policy which is used to provide the data owner’s control and share the data through encryption process in Cloud and IoT environment. The data are shared with the the help of cloud storage, even in presence of authorized users. The main method used in this research is Enhanced CP-ABE Serialization (E-CP-ABES) approach. Findings The results are measured by means of encryption, completion and decryption time that showed better results when compared with the existing CP-ABE technique. The comparative analysis has showed that the proposed E-CP-ABES has obtained better results of 2373 ms for completion time for 256 key lengths, whereas the existing CP-ABE has obtained 3129 ms of completion time. In addition to this, the existing Advanced Encryption Standard (AES) scheme showed 3449 ms of completion time. Originality/value The proposed research work uses an E-CP-ABES access control technique that verifies the hidden attributes having a very sensitive dataset constraint and provides solution to the key management problem and access control mechanism existing in IOT and cloud computing environment. The novelty of the research is that the proposed E-CP-ABES incorporates extensible, partially hidden constraint policy by using a process known as serialization procedure and it serializes to a byte stream. Redundant residue number system is considered to remove errors that occur during the processing of bits or data obtained from the serialization. The data stream is recovered using the Deserialization process.

File transfer by using a smartphone has some security issues like data theft by irresponsible parties. To improve the quality of data security systems on smartphones, in this research the integration of AES 256 bit algorithm by using MD5 hashing is proposed. The use of MD5 aims to increase the key strength of the encryption and decryption process of document files. The test results show that the proposed method can increase the key strength of the encryption and decryption process in the document file. Encryption and decryption time by using AES and MD5 combination is faster than using AES only on *.txt file type and reverse results for *.docx, *.xlsx, *.pptx and *.pdf file files.

The effective management and security of sensitive health data is becoming exponentially important to public health administration. This research examines and evaluates innovative ways to improve health data security in public health management systems to provide accessibility for authorized stakeholders. The study introduces the War Strategy Optimized Elliptic Curve Cryptography (WSO-ECC) encryption method for improving the security of primary healthcare medical records. The WSO-ECC technique, based on a war strategy framework, optimizes encryption and decryption processes by balancing exploration and exploitation phases, enhancing security while maintaining efficiency. It significantly reduces encryption and decryption times compared to traditional methods.The proposed method offers a robust solution for safeguarding medical information in public health management systems, demonstrating superior performance of 24.6 in encryption time, 23 decryption times, execution efficiency, and delay.