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Ramireddy Navatejareddy ◽  
Muthukuru Jayabhaskar ◽  
Bachala Sathyanarayana

<p>Image <span>encryption enables users to safely transmit digital photographs via a wireless medium while maintaining enhanced anonymity and validity. Numerous studies are being conducted to strengthen picture encryption systems. Elliptical curve cryptography (ECC) is an effective tool for safely transferring images and recovering them at the receiver end in asymmetric cryptosystems. This method's key generation generates a public and private key pair that is used to encrypt and decrypt a picture. They use a public key to encrypt the picture before sending it to the intended user. When the receiver receives the image, they use their private key to decrypt it. This paper proposes an ECC-dependent image encryption scheme utilizing an enhancement strategy based on the gravitational search algorithm (GSA) algorithm. The private key generation step of the ECC system uses a GSA-based optimization process to boost the efficiency of picture encryption. The image's output is used as a health attribute in the optimization phase, such as the peak signal to noise ratio (PSNR) value, which demonstrates the efficacy of the proposed approach. As comparison to the ECC method, it has been discovered that the suggested encryption scheme offers better optimal PSNR </span>values.</p>

Cryptography ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 1
Jongkil Kim ◽  
Yang-Wai Chow ◽  
Willy Susilo ◽  
Joonsang Baek ◽  
Intae Kim

We propose a new functional encryption for pattern matching scheme with a hidden string. In functional encryption for pattern matching (FEPM), access to a message is controlled by its description and a private key that is used to evaluate the description for decryption. In particular, the description with which the ciphertext is associated is an arbitrary string w and the ciphertext can only be decrypted if its description matches the predicate of a private key which is also a string. Therefore, it provides fine-grained access control through pattern matching alone. Unlike related schemes in the literature, our scheme hides the description that the ciphertext is associated with. In many practical scenarios, the description of the ciphertext cannot be public information as an attacker may abuse the message description to identify the data owner or classify the target ciphertext before decrypting it. Moreover, some data owners may not agree to reveal any ciphertext information since it simply gives greater advantage to the adversary. In this paper, we introduce the first FEPM scheme with a hidden string, such that the adversary cannot get any information about the ciphertext from its description. The security of our scheme is formally analyzed. The proposed scheme provides both confidentiality and anonymity while maintaining its expressiveness. We prove these security properties under the interactive general Diffie–Hellman assumption (i-GDH) and a static assumption introduced in this paper.

2021 ◽  
pp. 494-505
Alexandr A. Kuznetsov ◽  
Yurii Gorbenko ◽  
Anastasiia Kiian Anastasiia Kiian ◽  
Yuliia V. Ulianovska ◽  
Tetiana Kuznetsova

Pseudo-random number generator is an important mechanism for cryptographic information protection. It can be used independently to generate special data or as the most important element of security of other mechanisms for cryptographic information protection. The application of transformations in a group of points of elliptic and hypereliptic curves is an important direction for the designing of cryptographically stable pseudo-random sequences generators. This approach allows us to build  the resistant cryptographic algorithms in which the problem of finding a private key is associated with solving the discrete logarithm problem. This paper proposes a method for generating pseudo-random sequences of the maximum period using transformations on the elliptic curves. The maximum sequence period is provided by the use of recurrent transformations with the sequential formation of the elements of the point group of the elliptic curve. In this case, the problem of finding a private key is reduced to solving a theoretically complex discrete logarithm problem. The article also describes the block diagram of the device for generating pseudo-random sequences and the scheme for generating internal states of the generator.

Mohamad Tariq Barakat ◽  
Rushdi Abu Zneit ◽  
Ziad A. Alqadi

Multiple methods are used to hide secret messages in digital color images, and the most important and most common is the least significant bit (LSB) method. The LSB method is a known and exposed method, and anyone with programming experience can retrieve the secret message embedded in the digital image. In this paper research we will add some enhancements to improve the security level of LSB method to protect the embedded secret message from being hacked. A simple method of secret message cryptography will be used to encrypt the secret message before bedding it using LSB method. The method will be based on using color image as an image_key; this image_key will be resized to generate the needed secret private key used to encrypt-decrypt secret message. The length and the contents of the generated private key will dynamically change depending on the message length and the selected image_key. The selected image_key will be kept in secret without transmission and will be known only by the sender and receiver and it can be changed any time when needed. The proposed crypto_steganographic method will be implemented to show how it will increase the level o secret message protection.

2021 ◽  
Xiangyu Chang ◽  
Wei Li ◽  
Aimin Yan ◽  
Peter Wai Ming Tsang ◽  
Ting-Chung Poon

Abstract We propose an asymmetric cryptosystem based on optical scanning cryptography (OSC) and elliptic curve cryptography (ECC) algorithm. In the encryption stage of OSC, an object is encrypted to cosine and sine holograms by two pupil functions calculated via ECC algorithm from sender’s biometric image, which is sender’s private key. With the ECC algorithm, these holograms are encrypted to ciphertext, which is sent to the receiver. In the stage of decryption, the ciphered holograms can be decrypted by receiver’s biometric private key which is different from the sender’s private key. The approach is an asymmetric cryptosystem which solves the problem of the management and dispatch of keys in OSC and has more security strength than it. The feasibility of the proposed method has been convincingly verified by numerical and experiment results.

2021 ◽  
Ke Wang ◽  
Yuan Zhao ◽  
Song Luo ◽  
Zhi Guan

Accountable authority identity-based encryption (A-IBE) is an extension of identity-based encryption (IBE) in which private key’s source can be traced, i.e., whether the key comes from a private key generator or a user. SM9 is an official cryptography standard of China which defines a practical IBE scheme. In this paper, we construct a practical A-IBE scheme from the SM9-IBE scheme. Our A-IBE scheme has public traceability and is proven secure if the based SM9-IBE scheme is secure. Compared with other A-IBE schemes, our A-IBE scheme has better efficiency in encryption and decryption.

2021 ◽  
Vol 183 (41) ◽  
pp. 1-8
Ziad Alqadi ◽  
Yousif Eltous ◽  
Amjad Al Hindi

2021 ◽  
Sarvesh Tanwar ◽  
Sumit Badotra ◽  
Ajay Rana

Abstract PKI gives undeniable degree of safety by transferring the key pair framework among the clients. By constructing, a PKI we combine digital identities with the digital signatures, which give an end-to-end trust model. Basically, PKI is an attempt, which can simulate the real-world human analyzation of identity and reliability in a computerized fashion. In any case, the existing applications are centered on a tight trust model which makes them inadequate as an overall device for trust examination. After years of research, development and deployment, PKI still facing strong technical and organizational challenges such as attacks against Certificate Authorities (CA). CAs are the primitive component of PKIs which plays powerful role in the PKI model. CA must be diligent, creditable and legitimate. In any case, a technocrat who picks up control on a CA can use CA's certificate to issue bogus certificate and impersonate any site, such as - DigiNotar, GobalSign, Comodo and DigiCert Malaysia. In this paper we proposed an approach to reduce the damage of compromised CA/CA’s key by imposing Multiple Signatures (MS) after verifying/authenticating user’s information. One single compromised CA is not able to issue a certificate to any domain as multiple signatures are required. Private key and other perceptive information are stored in the form of object/blob. Without knowing the structure of class no one can access the object and object output stream. Proposed MS achieve better performance over existing MS schemes and control fraudulent certificate issuance with more database security. The proposed scheme also avoids MITM attack against CA who is issuing certificate to whom which is using the following parameters such as identity of Sender, Receiver, Timestamp and Aadhar number.

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