• Journal of Internet Computing and Services
• /
• v.4 no.4
• /
• pp.53-64
• /
• 2003

To perform the certificate validation on the user-side application induces the very considerable overhead on the user-side system because of the complex and time-consuming characteristic of the validation processing. Most of the time spend for performing the validation processing is required for the digital signature verification, since the verification accompanies with the cryptographic calculation over each certificate on the certificate path. In this paper, we propose a new certificate validation scheme using DSVP(Delegated Signature Validation Protocol) which can reduce the overhead for the user-side certificate validation processing. It is achieved by delegating the digital signature verification to CAs of the PKI domain. As the proposed DSVP is the protocol performed between a user and CAs, it is applied to the hierarchical PKI efficiently and used for delegating the digital signature verification reliably and safely, our proposed scheme can not only reduces the overhead for the validation processing by decreasing the cryptographic calculation but also improves the utilization of CAs by employing them to the validation processing.

• Journal of Communications and Networks
• /
• v.12 no.3
• /
• pp.201-208
• /
• 2010

We propose a new notion of metered signatures. Metered signature is an extension of k-times signatures in which a signer can generate only k signatures. However, the restriction of metered signatures can be more elaborate: It can be used k-times every day or to preserve the order of signed messages in some applications. Any violation of this regulation reveals a secret key or the signature on a predetermined message. The applications includes proxy signatures, limited free downloads, and the rating web site. We give two instances of metered signatures: One is based on the computational Diffie-Hellman problem (CDHP) using a bilinear map and the other is based on the RSA problem. In both schemes, the signature and certificate size and the verification cost are constant with respect to k. Further, we show that the proposed metered signatures admit batch verification of many signatures almost at one verification cost with small security loss.

• Proceedings of the Korean Information Science Society Conference
• /
• 2012.06c
• /
• pp.286-288
• /
• 2012

Facing the counterfeiting acts towards various products, many manufacturers implement ePedigree system to secure their supply chain. Using ePedigree, a distribution history including a valid product identifier from the manufacturer until the final retailer is recorded. And this ePedigree is signed by each involved supply chain party using digital signature. With this digital signature, any unauthorized alteration to the ePedigree document would generate a failed verification process. If there is a counterfeit product using a fake ePedigree document, it wouldn't be able to pass the verification process either. Hence, there wouldn't be any counterfeit product that could enter the legal supply chain and bought by the consumer. We are proposing to use ECDSA instead of RSA since it has faster performance and shorter key size. At a certain same security level, ECDSA only needs 163 bits, while RSA needs 1024 bits.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.7
• /
• pp.4912-4917
• /
• 2015

Fragile watermarking is a technique to insert a watermark into an image without significantly degrading its visual quality so that the watermark can be extracted for the purposes of authentication or integrity verification. And the watermark for authentication and integrity verification should be erased easily when the image is changed by filtering etc. In this paper, we propose a image block-wise watermarking method for image tamper proofing using digital signature. In the proposed method, a digital signature is generated from the hash code of the initialized image block. And The proposed method is able to detect the tampered parts of the image without testing the entire block of the watermarked image.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.27 no.4
• /
• pp.743-751
• /
• 2017

As smart phones are becoming popular, an operating system is being used at wearable devices, home appliances and smart TVs. A user is able to use various applications on devices with operating system, but there is an increased threat of hacker. Thus, the technology for detecting the forgery of applications is becoming more important on operating system. To detect the forgery of the application, a digital signature technology is used on the filed of application digital signature. According to W3C recommendation, the signing process of application digital signature must be performed at least twice, and the applications which are signed by the application digital signature have to be validated for all signature files when the application is installed in the operating system. Hence, the performance of the application digital signature validation system is closely related to the installer performance on the operating system. Existing validation system has performance degradation due to redundancy of integrity verification among application components. This research was conducted to improve the performance of the application digital signature validation system. The proposal of validation system which is applied proxy system shows a performance improvement compared to the existing verification system.

• Journal of Information Processing Systems
• /
• v.13 no.6
• /
• pp.1516-1526
• /
• 2017

Many organizations today use patch management systems to uniformly manage software vulnerabilities. However, the patch management system does not guarantee the integrity of the patch in the process of providing the patch to the client. In this paper, we propose a method to guarantee patch integrity through dual electronic signatures. The dual electronic signatures are performed by the primary distribution server with the first digital signature and the secondary distribution server with the second digital signature. The dual electronic signature ensures ensure that there is no forgery or falsification in the patch transmission process, so that the client can verify that the patch provided is a normal patch. The dual electronic signatures can enhance the security of the patch management system, providing a secure environment for clients.

• Bulletin of the Korean Mathematical Society
• /
• v.53 no.4
• /
• pp.1051-1069
• /
• 2016

Combining the concept of self-certified public key and message recovery, Li-Zhang-Zhu (LZZ) gives the proxy signature scheme with message recovery using self-certified public key. The security of the proposed scheme is based on the discrete logarithm problem (DLP) and one-way hash function (OWHF). Their scheme accomplishes the tasks of public key verification, proxy signature verification, and message recovery in a logically single step. In addition, their scheme satisfies all properties of strong proxy signature and does not use secure channel in the communication between the original signer and the proxy signer. In this paper, it is shown that in their signature scheme a malicious signer can cheat the system authority (SA), by obtaining a proxy signature key without the permission of the original signer. At the same time malicious original signer can also cheat the SA, he can also obtain a proxy signature key without the permission of the proxy signer. An improved signature scheme is being proposed, which involves the remedial measures to get rid of security flaws of the LZZ et al.'s. The security and performance analysis shows that the proposed signature scheme is maintaining higher level of security, with little bit of computational complexity.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.2
• /
• pp.377-387
• /
• 2009

Digital signatures not only provide a way of guaranteeing the integrity of data but also establish the identity of the signer. However, basic digital signature format which contains only the signature of the signer does not guarantee the correctness of its creation time, and it can not remain valid over long periods. This paper proposes a system which integrates timestamp service into digital signatures. The system provides online services for the creation and verification of long term digital signatures which can give the guarantee of the correctness of their creation times and can be proved to be valid over long periods. The proposed system can be used in the various areas such as e-commerce contracts, document archival services, and invoice applications, which requires long term digital signatures. The proposed system is tested with the KRISS timestamp service system.

• Journal of the Korea Society of Computer and Information
• /
• v.18 no.6
• /
• pp.47-54
• /
• 2013

In this paper, we proposed an efficient digital authentication service system for the vehicle data collected from digital tachograph. In domestic, There is no method available to verify that information has not been forged and reliable information for collected vehicle data. The proposed method in this paper can prove transmitted vehicle data that have not been forged using the signature value. The signature value of digital authentication is produced with the digital signature generation key after obtaining the hash value of vehicle data. It is achieved through checking the stored hash value and the hash value match that is obtained with the digital signature verification key from the digital signature value. We confirmed the proposed system can ensure reliability of vehicle data through the system implementation and experiment.

• Journal of the Korea Society of Computer and Information
• /
• v.9 no.2
• /
• pp.41-48
• /
• 2004

Access control protocol have verified security of external mobile terminal that access to inner information sever at Ubiquitous ages. In this paper, I would design for If Access Control Protocol of considering operation time when make cipher digital signature. Public key are used Individual identification number that issued from certify communication company, and cipher algorithm are used ECDSA definition factor for generation and verification of digital signature and it used Elliptic Curve with over 160 bit Key. Also, Access control operate on If level that designed IPv6 frame architecture. I would conclude that IP Access Control Protocol have verified security and improved performance in operation time more 4 times than before protocols when through the communication of use cipher digital signature for authentication and verification.