A Proposed Genetic Algorithm Attack for Public Key Cryptosystem

The invention of public-key cryptography was of central importance to the field of cryptography and provided answers to many key management problems for large scale networks. For all its benefits, however, public-key cryptography did not provide a comprehensive solution to the key management problem. Indeed, the possibilities brought forth by public-key cryptography heightened the need for sophisticated key management systems to answer questions such as the following:"How can I easily encrypt a file once for a number of different people using public-key cryptography?""If I lose my keys, how can I decrypt all of my files that were encrypted with those keys?""How do I know that I really have Alice’s public key and not the public key of someone pretending to be Alice?""How can I know that a public key is still trustworthy?"The paper discusses public key cryptography and its use in applications such as Key Agreement, Data Encryption and Digital Signature. The paper discusses some public key algorithms such as DH, RSA, and DSA and also gives working explanations of these algorithms.KeywordsShared SecretCertificate AuthorityCipher TextHash CodeDigital CertificateThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

In the Internet, securing email has always been an important issue. Various standards and products have been created. One of the most successful standards is OpenPGP by J. Callas et al. (1998), which uses public key cryptography (R. L. Rivest et al. (1977) and others) and is implemented in systems like Pretty Good Privacy according to P. Zimmerman (1995), Gnu Privacy Guard by W. Koch, Hushmail, and others. A well-known difficulty with the use of public key cryptographic systems is the verification and distribution of the public keys. OpenPGP solves the problem of verifying the authenticity of a public key by having users certify each others keys, building a Web of Trust described by P. Feisthammel (1997) by bundling these key certificates with each users public key. Therefore, adding a new public key and updating an existing public key (or replacing it by a new version) are the two most important operations of any PGP public key repository. To allow easy distribution of PGP public keys, the OpenPGP community established a network of open access public keyservers, allowing users of OpenPGP software to freely exchange public keys. The nodes of this keyserver network synchronise their database by exchanging new public keys and key updates amongst each other, virtually building one global key database. At the moment, this synchronisation is done with an inefficient and ineffective email based protocol. This paper describes the implementation of an alternative protocol - KX - on the popular pksd keyserver according to M. Horowitz (1997), based on direct TCP connections between the keyservers and unambiguous identifiers for every key update or new key. With the dropping of the dependency on a working mail system and the improved fault mechanisms, KX is a lightweight alternative in terms of used network, disk and CPU resources.

In the early years after the invention of public key cryptography by Diffie and Hellman in 1976, the design and evaluation of public key cryptosystems has been done merely in ad-hoc manner based on trial and error. The public key cryptosystem said to be secure as long as there is no successful cryptanalytic attack on it. But due to various successful attacks on the cryptosystems after development, the cryptographic community understood that this ad-hoc approach might not be good enough. The paradigm of provable security is an attempt to get rid of ad hoc design. The goals of provable security are to define appropriate models of security on the one hand, and to develop cryptographic designs that can be proven to be secure within the defined models on the other. There are two general approaches for structuring the security proof. One is reductionist approach and other is game-based approach. In these approaches, the security proofs reduce a well known problem (such as discrete logarithm, RSA) to an attack against a proposed cryptosystem. With this approach, the security of public key cryptosystem can be proved formally under the various models viz. random oracle model, generic group model and standard model. In this chapter, we will briefly explain these approaches along with the security proofs of well known public key cryptosystems under the appropriate model.

Certificateless threshold signature scheme from bilinear maps

The elliptic curve cryptography is almost used in the literature to develop the public key cryptosystems. A new general-purpose symmetric key cryptosystem using elliptic prime curves is proposed in this paper. For a given prime number P, there are many elliptic prime curves on which each point in the quadrant (0,0) to (P-1,P-1) lays. The set of minimum number of eligible elliptic prime curves for a given prime number P constitutes a lookup table that is the secret key of the proposed cryptosystem. The sender can pick up one eligible elliptic curve for each 2n-bit plaintext block. The sender sends two integers cipher for each 2n-bit plaintext block with encryption rate = 0.8. Moreover, a small prime number can be used efficiently with high security and good robustness against brute force attack.

Objective: A brand new version of RSA, known as Multi Key Generation Scheme generation scheme, has been proposed. For sensitive information, our schemes will be a useful resource in replacing the records among cloud to IoT and IoT devices. Whilst cryptography belongs to the asymmetric type, then it has public and personal keys. Methods/Statistical Analysis: For reminiscence performance, our scheme reuses the RSA scheme with a Diophantine shape of the nonlinear equation. Furthermore, our scheme overall performances well and this is especially because of the use of RSA public key. Findings: MKGS does not require multiplicative inverse function or prolonged Euclid’s algorithm. Finally, we\'ve made an experimental result on diverse stages of MKGS P.C such as key generation, encryption, and decryption via varying the N-bit modulo bits from 1K to 10K. Application/Improvements: We can develop new features rather than using Modulation bits. Keywords: Cloud computing, Cryptography, Multi Key, Public Key Cryptosystem, IoT, RSA

Public Key Cryptography enables entity authentication protocols based on a platform's knowledge of other platforms' public key. This is particularly advantageous for embedded systems, such as FPGA platforms, with limited or none read-protected memory resources. For access control systems, an access token is authenticated by the mobile system. Only the public key of authorized tokens needs to be stored inside the mobile platform. At some point during the platform's lifetime, these might need to be updated in the field due to loss or damage of tokens. This paper proposes a holistic approach for an automotive access control system based on Public Key Cryptography. Next to a FPGA-based hardware architecture, we focus on a secure scheme for key flashing of public keys to highly mobile systems. The main goal of the proposed scheme is the minimization of online dependencies to Trusted Third Parties, Certification Authorities, or the like, to enable key flashing in remote locations with only minor technical infrastructure. Introducing trusted mediator devices, new tokens can be authorized and later their public key can be flashed into a mobile system on demand.

In traditional public key signature, the public key of a signer is essentially a random string selected from a given set. It is infeasible to prove that a party is indeed the signer for a given signature. In general, the public key of a user needs a management authority to authenticate it. It results in that traditional public key cryptosystem (PKC) requires high maintenance cost for certificate management. Although, identity based cryptosystem (IBC) reduces the overhead of management, it suffers from the drawback of key escrow. Certificate-based cryptosystem combines the advantage of both PKC and IBC as it avoids the usage of certificates and does not suffer from key escrow. Recently, Liu et.al proposed an efficient Certificate-based signature and showed that the scheme was secure in the random oracles. Unfortunately, this paper shows that the scheme is insecure and discusses the flaws in their security proof. Then the corresponding attacks are given. To overcome the flaws, an improved scheme is proposed and the result shows that the scheme is provable secure against two game attacks of certificate-based signature in the random oracle model. The security is closely related to the computational Diffie-Hellman problem.KeywordsSecurity analysisattackimproved schemethe CDH problemcertificate-based signature

A public key encryption cryptography system can be utilized to generate ciphertext of a message using a public key. However, this public key encryption cryptography system cannot be utilized if you want to generate ciphertext using several different keys. Solving the problems above can use the Chosen Ciphertext Secure Public Key Threshold Encryption scheme but are the securities from Threshold Encryption really strong in securing messages, therefore the above problems can be analyzed for Data Security Against Chosen Ciphertext Secure Public Key Attacks Using Threshold Encryption Schemes. The work process starts from Setup which functions to generate the server's private key and public key. Then, the process is continued with ShareKeyGen which functions to generate private keys based on the user's identity. After that, the process continues with ShareVerify which serves to verify the key generated from the ShareKeyGen process. The process will be continued again with Combine which serves to generate a private key that will be used in the decryption process. After that, the process will continue with the encryption process of the secret message. The ciphertext obtained will be sent to the recipient. The receiver verifies the ciphertext by running ValidateCT. Finally, the ciphertext is decrypted by running Decrypt. The software created can be used to display the workflow process of the Threshold schema. In addition, it makes it easier to test intercepts of ciphertext messages to other users so that generic securities analysis is carried out in testing the resulting ciphertext. The results of the implementation of Threshold Encryption algorithm scheme can protect important personal data, because it involves human rights, namely the right to access, the right to delete, the right to correct, the right to be corrected and the right to transfer personal data safely from attacks.

In 1976 Diffie and Hellman [152] described the framework for public-key cryptography. It was not until 1978 that three designs for public-key cryptosystems were published. Rivest, Shamir, and Adleman [431] showed how the discrete logarithm and factorization problems could be used to construct a public-key cryptosystem. This is the well-known RSA cryptosystem. Merkle and Hellman [339] used the knapsack problem in their construction. McEliece [329] built a system based on error correcting codes. Later in 1985 ElGamal [163] designed a public-key cryptosystem using the discrete logarithm problem. Koblitz [283] and Miller [346] suggested the use of elliptic curves in the design of public-key cryptosystems. Nowadays, there are quite a few more suggestions as to how to design public-key cryptosystems, but none so popular as the RSA and ElGamal cryptosystems.

Objectives: Public key cryptography helps in achieving information security in wireless networks. Public key will be issued by CA (Certificate Authority). But having CA in wireless network makes it vulnerable to various attacks. Hence distributed cache was proposed where each node in network caches public key of some nodes existing in network in its cache and request to obtain keys not cached will be made via trusted nodes. Due to limited memory only few keys can be cached. There exists an optimal threshold value for caching keys so that equal number of both local nodes and remote nodes public keys can be cached. Methods: Random replacement policy was used for updating cache contents, where if a node’s local/ remote key cached ratio exceeds optimal ratio then a key will be randomly chosen from the cache and will be removed. Here we propose implementation of bloom filter in cache to cache public key of nodes existing in network. Findings: By using bloom filter of large size, more number of public keys can be cached thereby providing space and time advantage and reduces query cost with increased usage of memory. MAC (Media Access Control) id and PSN (Processor Serial Number) are used for uniquely identifying each node in network and are stored in encrypted format. When mismatch is found in encrypted MAC id and PSN, then that node is determined to be malicious node and its id will be notified to all nodes in network thus excluding the node from making any communication to other nodes in the network. Applications: Used for checking an element’s presence in the set thus reducing I/O lookup when large data set is used. Used as an alternative to cache as it uses limited memory more efficiently than cache does.

Most public-key cryptosystems frequently implemented have been proven secure on the basis of the presumed hardness of two mathematical problems: factoring the product of two large primes (FP) and computing discrete logarithms (DLP). At present, both problems are believed to be computationally infeasible with an ordinary computer. However, a quantum-computer having the ability to perform computations on a few thousand qbits could solve both problems using Shor's algorithm [23]. Although a quantum computer of this dimension has not been reported, development and cryptanalysis of alternative public-key cryptosystems seem suitable. To achieve acceptance and attention in practice, they have to be implemented efficiently. Furthermore, the implementations have to perform fast while keeping memory requirements low for security levels comparable to conventional schemes. The McEliece encryption and decryption do not require computationally expensive multiple precision arithmetic. Hence, it is predestined for an implementation on embedded devices. The major disadvantage of the McEliece public-key cryptosystem(PKC) is its very large public key of several hundred thousands bits. For this reason, the McEliece PKC has achieved little attention in the practice. Another disadvantage of the McEliece scheme, like many other schemes, is that it is not semantically secure. The quasi-dyadic McEliece variant proposed by Barreto and Misoczki addresses both problems. In this work we provide an implementation of this alternative public-key cryptosystem, which is semantically secure and uses a 40 times smaller public key and a five times smaller secret key compared to a previously published implementation [6].

Public key encryption schemes developed based on learning with error problem became popular for homomorphic encryption, and are proved as secured schemes based on the worst-case hardness of short vector problems. Homomorphic encryption allows computations over the cipher text without decryption. Implementation of the scheme is not considered to be practical because of its larger public keys and larger cipher texts. Large public key and cipher texts require huge space in the cloud storages. However, there are some approaches proposed to shorten the cipher texts and public keys of LWE-based homomorphic encryption scheme. The objective of the paper is to introduce an idea to shorten the public keys and cipher texts in the storage. Also, support homomorphic addition operation on reduced cipher texts. The aim of the paper is not only to give the practical implementation of standard LWE-based homomorphic encryption operation (Addition) on the reduced cipher texts and also the performance of the proposed scheme.

With the development of modern communication technology, an increasing number of people are choosing to communicate end-to-end over the network. However, the risk of information leakage and data tampering has also increased, and the issue of information confidentiality has become an increasing concern. Among the existing encryption algorithms, symmetric encryption algorithms cannot securely manage the key and share the key between communication parties; ECC and other public key encryption algorithms have problems such as slow encryption and decryption speed, low encryption strength, etc. In addition, key management is still not guaranteed to be very secure; conventional hybrid encryption algorithms need to manage two different types of keys, and key management may be very complicated and prone to key leakage or theft. Based on the problems of the above algorithms, this paper proposes RSA-Co-CP-ABE Architecture, which uses socket communication, encrypts the RSA public key passed from Client to Server with CP-ABE, encrypts the confidential message with the public key passed from Client at Server, and finally sends the encrypted message to Client. This scheme has higher flexibility than the traditional symmetric encryption and public key encryption schemes, and by using CP-ABE encryption, it can realize attribute-based access control. And RSA encryption can make the scheme make a better balance between encryption and decryption efficiency and encryption strength. In addition, because the communication is transmitted in full cipher text during the communication, the scheme can effectively resist tampering or stealing by man-in-the-middle attacks.

Cryptanalysis of Zuhua Shao key Authentication Scheme