Users are required to set passwords that are both complex and not included in leaked lists, with the recent increase in unauthorised access due to password list attacks. When password security is evaluated by the user, the burden on the user is large and impractical due to the increased size of the compromised password list. Therefore, there are methods to evaluate passwords on an external server, but there is a possibility that passwords may be compromised due to eavesdropping by the server administrator. In this paper, we propose, implement and evaluate an outsourcing password evaluation system using Intel SGX, which can prevent passwords from being eavesdropped.

In recent years, wireless sensor network technology has been frequently used in various fields, thereby making it increasingly important to ensure that the data being transferred remains confidential. Symmetric-key cryptography, which does not require high computing capacity, is a method that is generally used because the computing and memory requirements of sensor nodes are low. An implementation of symmetric-key cryptography is needed in order to achieve high-speed processing of sensor nodes. In this paper, we propose and evaluate a fast implementation scheme of the Advanced Encryption Standard using an inline-assembler that is suitable for the ATmega1281 microcontroller. This microcontroller is a part of the Atmel AVR series and is often equipped with sensor nodes for use in wireless sensor networks.

A sensor node has extremely limited power supply capacity and operation performance, therefore, key management schemes that can be achieved with less calculation in sensor networks have been proposed. However, these key management schemes cannot be flexibly applied to various connection topologies and network configurations. In this paper, we propose a key management scheme that can be generally used in a network that supports various connection topologies and that is capable of adding new nodes. Finally, we implement and evaluate our scheme.

Attribute information such as age, gender, and job is used in user registration and questionnaires.A verifier must consider what method to use for confirming attribute information when it is used online.For instance,the reliability of the information varies with the method:the verifier can accept the user's claim,confirm by certificate,confirm face-to-face or use other methods. Therefore, the reliability of attribute information becomes a problem when strict verification is necessary for a contract.In this paper,we consider the reliability of registration and attribute information that is exchanged and propose a method by which the reliability of attribute information and its grounds can be returned when attributes are exchanged.

In this paper, we improve a decentralized management method for uniquely accessible attribute information. The previous method has the problem of the inconsistency in access policy. In our new method,the user has always to redirect from the identity provider to the attribute provider, because the user cannot make requests directly to the attribute provider. Our method makes it possible for the identity provider alone to manage the access policy. As a result,the problem of inconsistency in access policy is solved. Moreover, illegal requests are prevented from using this redirection.

There are a variety of certificates to prove the identity and the attribute on network. Public key certificate is used to prove the identity of the user and attribute certificate is used to prove the attributes of the user It is necessary to bind attribute certificate to public key certificate to prove the owner of the attributes because attribute certificate does not contain the identity information. Some attributes have the derivation relationship between attributes. Therefore, branch attributes should be revoked when origin attributes are revoked. It is necessary to do it at once. The naive method cannot show the relationship with derivation attributes directly. Therefore, the naive methods have the following problems. First, the relationship between attributes is not written into attribute certificate. Second, branch attribute certificate cannot be revoked at once when origin attributes are revoked. In this paper, we propose the method to shorten the revocation delay of attribute certificate with the relationship by using an attribute authentication method that can show the relationship between attributes. Our method makes it possible to invalidate branch attribute certificate at once when origin attribute certificate is revoked, and protects against illegal use of attribute certificate that use the time difference of revocation processing

When the Web services are used, there is a case that they need not identify who is the user if the user is the regular user. In this paper, we propose the method that the service based on authority can be used by public-key certificate and attribute certificate without identifying. As a result, the user can take the services though the user with a regular authority is not identified by the service server. Moreover, the service server confirms user is a regular user, and can provide the services without identifying the user. Our method makes it possible to protect the user's usage information.