ABSTRACT The necessity of the large data storage is the basic requirement of any data transmission among the authenticated users which guarantee’s them the confidentiality of the message sent and received among the users or in the group

ABSTRACT

The necessity of the large data storage is the basic requirement of any data transmission among the authenticated users which guarantee’s them the confidentiality of the message sent and received among the users or in the group. however, the anonymity of the service clients is the most essential aspect of the privacy. Since the anonymity is the major aspect that services also should provide real and fine grained encrypted data sharing such that the user is allowed to share a ciphertext data among the authenticated users under applied conditions.
Thus this project provide for the first time proposes a Multi-Sharing Information And Large Data Storage Using Ciphertext mechanism to achieve the above mentioned properties. In this project the proxy re-encryption methods are applied that enables ciphertext to be securely and conditionally shared among sender and receiver without leakage and loss of data. Furthermore, This project shows the new primitive standard model for the chosen ciphertext attacks.

1. INTRODUCTION

In today’s need of data sharing security is the major concern for any services which provides large data storage and the data sent by the individual user must be secure and accessed by the authenticated user for which one of the key consideration of the security is the anonymity of the service client. The service that is used for storing must provide practical and encrypted data sharing among the authenticated user by the ciphertext and the data which is being shared must be passed on to the other authenticated users i.e multisharing of domain encrypted form under specified condition. the required features are obtained by new technique for large data storage i.e Multi-Sharing Information And Large Data Storage Using Ciphertext .
In this technique the advantage of proxy re-encryption methods are applied that enables ciphertext to be securely and conditionally shared among authenticated users multiple times and it also ensures the underlying message and identity information of ciphertext sender and receiver are not lost and leaked to the un-authenticated user.

Customized Lead Pages with Lead Generation in Real Estate

BMSIT&M/Department of MCA/1BY14MCA17/2016-17 Page 3

mentioned.
Here the user has a feasibility of creating market reports by own. After creating market
reports the user can view it by clicking on the link and the same will open with agent address,
profile and company details.
Objective of the Study
The objective of the study is to ease the way of searching homes in a particular location. This
system provides the previous year’s market reports from which the user can easily know the
details of the particular house.

1.2 Problem Formulation
The problem formulation helps to identify the problems involved in the existing system and
also the solution to overcome the problems identified in the existing system. The problem in
the existing system of Real Estate is the manual and time consuming process for searching of
homes in a desired location and to know about the previous market situation of the house.
The solution to the problem is the web application or the public facing site where anyone can
access the site and search for the homes in their desired location and can also view the market
reports and can do home valuation by sitting at one place without visiting the house which
saves time
1.1 Problem Formulation
The problem formulation helps to identify the problems involved in the existing system and also the solution to overcome the problems identified in the existing system. The problem in the existing system is we cannot prevent some sensitive personal information from being leaked to the cloud server this is because traditional encryption system that do not consider the anonymity of ciphertext for sender and receiver.
Cloud server has the capability to decode the encrypted information from the proxy server due to this the traditional encryption is vulnerable for the leakage of data which may lead to compromising of business and compromising of data leakage.

2. Company Profile

Raksha technology is a global services provider delivering technology-driven business solutions that meet the strategic objectives of our clients. Since it is started in 2012, for developing software.
Raksha technology delivers unmatched business value to customers through a combination of process excellence, quality frameworks and service delivery innovation. We seek to forge a three-way partnership between our customers, our consultants and ourselves, which will sustain over the long term. We work to create an environment of performance, co-operation and pride in belonging to this partnership.

3. LITERATURE SURVEY

3.1 Existing System
In the existing system cryptographic encryption mechanisms we used the traditional approach to send and receive data for instance PUBLIC KEY ENCRPTION(PKE) allows a data sender to encrypt the data under the public key of receiver such that no one except the valid recipient can gain access to the data. Nevertheless this does not satisfy all the requirement of users in the scenario of large data storage.
Suppose a hospital stores its patients medical record in a cloud storage system and meanwhile the records are all encrypted so as to avoid the cloud server from accessing to any patients medical information after a record is encrypted and further uploaded to the cloud only these specified doctors can gain access to the record by using some traditional public key encryption(PKE),identity based encryption(IBE),attribute-based encryption(ABE),the confidentiality of the record can be protected effectively.

3.2 Proposed System
In the Proposed system, we introduced a unique notion, anonymous multi-hop identity-based conditional proxy re-encryption, to preserve the anonymity for ciphertext sender/receiver, the required data will be shared for the user condinationally for multiple recipient.
In the proposed framework, we de?ne four types of security models for various functional purposes, The security model of MH-IBCPRE is the fundamental one, in which a challenger plays the game with the adversary to launch Chosen-Cipher content Attacks (CCA) to the original ciphertext and re-encrypted ciphertext in order to test the leakage of data , if the challenger wins the game then the model concludes that it is vulnerable to attacks if not then the models concludes that it is secure against the chosen attack.

3.3FEASIBILITY STUDY
The feasibility study plays a major role in the analysis of the system. A feasibility study is an evaluation or analysis of the potential impact of a proposed project, following are the three classifications in attainability concentrate specifically. 2
3.2.1 Technical Feasibility: The technical feasibility assessment is focused on gaining an understanding of the present technical resources of the organization and their applicability to the expected needs of the proposed system. It is an assessment of the equipment and programming and how it addresses the issue of the proposed framework.
3.2.2 Operational Feasibility: Operation feasibility always determines how the existing system is being resolved and how it has been implemented with the changes in the proposed system and the uses cases that we are going to use to test the feasibility of the requirement by overcoming the vulnerable attacks.
3.2.3 Financial Feasibility: The financial system feasibility study had been the major contrast for any business to be completed successfully as it determines the various criteria such as the technology, resources, capital, revenue, time etc.

3.3Tools and Techniques
The tools are basic necessity for any project to run successfully so some useful ways to deal with the latest technology to be used for the development of the project hence it is the team which decides the tool that best supports for their requirement.
In this project we have choosen certain debugging tools and one application development tool in order to run and execute our code for example for the from end applications we are using HTML5 for structuring and presenting the content on the website as it is supported by the multimedia features and to support the validations check we have used JAVASCRIPT libraries and extensions to load it.
One more such tool we have used is the Oracle 10g which is the most essential aspect of the project to persist the data and for the security aspect as it has various inbhuilt features that secures the data with rollback functionality if failure occurs at certain instance.
In this project we plan to propose a ciphertext sharing dataimplementing the system to accomplish the properties one such property is anonymitywhere in we try to check the anonymity of the user for which we have used a SOAL tool to verify the authenticity of the data.
In additionally consider the situation where an intermediary plots with representative to trade off the fundamental message and the mystery key of delegator. Here, the insurance of the message is extremely dif?cult to accomplish as the agent can simply unscramble the comparing ciphertext for the intermediary. The mystery key of the delegator, notwithstanding, is conceivable to be secured.
For the de?nition of arrangement assaults model, we permit a foe to obtain all re-encryption keys, and the foe wins on the off chance that it yields a substantial mystery key of an uncorrupted client. take note of that our de?nition is in the particular model in which the enemy needs to yield an objective character at the beginning of the amusement.

3.4 Hardware and software Requirements
Hardware Requirements:
Following are the hardware used in this project.
Processor : Intel Pentium-IV
Ram : 612 MB
Hard Disk : 50GB

Software Requirements: Following are the software used in this project Operating System : Windows xp /w 7/ w 8.
Front End : Java.
Back End : Oracle 10G.
User Interface : HTML, CSS.
Client-side Scripting : JavaScript
Programming Lang : Java.
Web Applications : JDBC, Servlets.
Database : Oracle 10g.

4. SOFTWARE REQUIREMENTS SPECIFICATIONS
It for the most part portrays the depiction of a product prerequisite that should be created it is possible that it can be practical or non-utilitarian, the product necessities archive (additionally called programming prerequisites particular or SRS) is an official record of what ought to be executed. It’s likewise utilized as an agreement between the framework purchaser and the product designers. It ought to incorporate both; client and framework necessities. Normally, the client necessities are characterized in a prologue to the framework prerequisites. In different cases, particularly if there are expansive number of necessities, the definite framework prerequisites might be introduced in a different archive.
4.1 Users
The client necessities for a framework ought to portray the practical and non-utilitarian prerequisites with the goal that they are reasonable by clients who don’t have specialized learning. You ought to compose client necessities in normal dialect provided by basic tables, frames, and natural outlines. The prerequisite report should exclude subtle elements of the framework plan, and you shouldn’t utilize any of programming language, or formal documentations

4.2 System Requirements
The framework prerequisites then again are extended variant of the client necessities that are utilized by programming engineers as the beginning stage for the framework outline.
They include detail and clarify how the client necessities ought to be given by the framework. They shouldn’t be worried about how the framework ought to be actualized or composed.
The framework prerequisites may likewise be composed in characteristic dialect however different routes in view of organized structures, or graphical documentations are normally utilized.

4.3 Functional Requirements
An utilitarian prerequisite portrays what a product framework ought to do, A case of a practical necessity would be:
A framework must send an email at whatever point a specific condition is met (e.g. a request is set, a client joins, and so on).
The useful necessity is depicting the conduct of the framework as it identifies with the framework’s usefulness.

4.4 Non-Functional Specification
A non-functional requirements places the constraints on how the system will do so, for Ex:A related non-functional requirement for the system may be:
• Emails should be sent with a latency of no greater than 12 hours from such an activity.
• The non-functional requirement elaborates a performance characteristic of the system.
Ordinarily non-utilitarian prerequisites fall into zones, for example,

• Accessibility

• Capacity, current and estimate

• Compliance

• Documentation

• Disaster recuperation

• Efficiency

• Effectiveness

• Etc

• Non-useful necessities are at times characterized regarding measurements (something that can be estimated about the framework) to make them more unmistakable. Non-practical prerequisites may likewise depict parts of the framework that don’t identify with it’s execution, yet rather to it’s advancement after some time (e.g. viability, extensibility, documentation, and so forth).

5. SYSTEM DESIGN

5.1 System Perspective
The System design explains about the system perspective of the proposed system. It explains
about the interaction between modules and API’s. This chapter includes the system
architecture, context diagram and the data flow diagrams of the proposed system.
The System design explains about the system perspective of the proposed system. It explains
about the interaction between modules and API’s. This chapter includes the system
architecture, context diagram and the data flow diagrams of the proposed system.
The System design explains about the system perspective of the proposed system. It explains
about the interaction between modules and API’s. This chapter includes the system
architecture, context diagram and the data flow diagrams of the proposed system.
The outline stage comes after a decent comprehension of client’s prerequisites, this stage characterizes the components of a framework, the parts, the security level, modules, design and the distinctive interfaces and kind of information that experiences the framework.
A general framework configuration should be possible with a pen and a bit of project to decide how the framework will look like and how it will capacity, and after that a nitty gritty and extended framework configuration is delivered, and it will meet all utilitarian and specialized prerequisites, intelligently and physically.In this project, this mean to propose a ciphertext imparting component to the accompanying properties.

• Anonymity: given a ciphertext, nobody knows the personality data of sender and recipient.
• Multiple beneficiary upgrade: given a ciphertext, the recipient of the ciphertext can be redesigned in numerous times. In this paper, we allude to this property as “multi-jump”.
• Conditional sharing: a ciphertext can be ?ne-grained imparted to others if the pre-speci?ed conditions are satis?ed.4

5.2 METHODOLOGY
There are four methods we are using to perform job easily.
1. Gathering Data
2. Data Encryption and Anonymity
3. Multiple receiver update
4. Conditional sharing

1. Collect Data(Gathering Data)
In this module first we have to collect the data’s here we are using patient dataset. That patient dataset it contains some attributes such as name, age, gender, month, location and symptoms of the patients .After the data has been chosen we have to preprocess the data’s .Preprocessing is nothing but a data cleaning it is the process of eliminating unwanted data unwanted noise values etc..

2. Data Encryption and re-encryption and Anonymity

After collect the data’s we need to encrypt the data. Here we use the encryption algorithm called password based encryption with MD5 and DES. The MD5 algorithm is a widely used hash function producing a 128bit hash value. Although MD5 was initially designed to be used as a cryptographic hash function. In this module we encrypt the data of patient using PKE with MD5 and DES. Then we upload the data into the HDFS location. That is in HADOOP, HADOOP file system was developed using distributed file system design. HDFS holds very large amount of data and provides right to use.

3.Multiple receiver update
In this module multiple no of receiver enter into the cloud and they send their data’s such as their profile such as ID,PASSWORD and CATEGORY to the sender. Category define the data which is the receiver going to receive from sender and also receiver category.
For each and every individual receiver we generate the unique ids .Because receiver information has been anonymized and after that only it will be forwarded to sender.
For that here we are generating the unique id for each every individual receiver in the cloud. So in this modules we define the individual receiver updates by updating the user’s profile and updating the categories.

4.Conditional sharing

After the multiple receiver updating process is completed. Conditional sharing is going to be processed as in our implementation conditional sharing is takes place based on the user’s category and their receiver receiving data category . Here we check the condition it both the category are similar means receiver will be authenticated and he/she can receive their data in ciphertext format only.

5.3 Context Diagram

6. DETAILED DESIGN

6.1 Use-Case Diagram

Fig 6.1.1 system Use Case Diagram

Fig 6.1.2 Defense Ministry Use Case Diagram

Fig 6.1.2 Defense Ministry Use Case Diagram

Fig 6.1.3 Defense Ministry Use Case Diagram

Fig 6.1.3 Defense Ministry Use Case Diagram

6.1.4 Agent Use Case Diagram

Fig 6.1.4 Agent Use Case Diagram

Fig 6.1.5 Citizen Use case Diagram

6.2 Sequence Diagram:

Fig 6.2.1 DefenceMinistry sequence Diagram

6.2.2 Agent sequence Diagram

6.2.2 Agent sequence Diagram

6.2.3 Change Password Sequence Diagrams

Fig 6.2.3 Change Password Sequence Diagrams

6.3 Collaboration Diagrams
6.3.1 Agent Sequence Collaboration Diagrams

6.3.1 Agent Sequence Collaboration Diagrams

6.3.2 Login Sequence Collaboration Diagram

6.3.3 Registration Sequence Collaboration Diagram

6.4 Activity Diagram

6.4.1 Activity Diagram for Secret Agency’s Chief

Fig 6.4.1 Activity Diagram for Secret Agency’s Chief

6.4.2 Activity Diagram for Agent

6.4.2 Activity Diagram for Agent

6.4.3 Activity Diagram for Defense Ministry

Fig 6.4.3 Activity Diagram for Defense Ministry

6.5 Database Design:
Address

CASES_ASSIGN_CHIEF

CASSES

TIPS_SUGGESTIONS

User details

Agency

CASES_ASSIGN_AGENT

Case details

Cases_ASSIGN

inbox table

Outbox

login details

7. IMPLEMENTATION

The need of enormous information stockpiling, along these lines, is more alluring than any other time in recent memory. A fundamental security necessity of enormous information stockpiling is to ensure the con?dentiality of the information. Luckily, some current cryptographic encryption instruments can be utilized to full ?ll the necessity. For example, Public Key Encryption (PKE) permits an information sender to scramble the information under the general population key of collector such that nobody with the exception of the legitimate beneficiary can access the information.

7.1 Screen shots:

7.1.1 Load DataSet

7.1.2 Open….

7.1.3 Load Dataset

7.1.4 Loadinto HDFS

7.1.5 Loadinto HDFS

7.1.6 Messages

?
7.1.7 Data Encryption

7.1.8 Proxy ReEncryption

7.1.9 Proxy ReEncryption

7.1.10 Store Encrypted Data

7.1.11 Data Sharing

Run Receievr1.java and Receiver2.java

7.1.12 Receiver-1

7.1.13 Receiver-2

7.1.14 Receiver-3

7.1.15 Receiver Updations

7.1.16 Receiver Updations

7.1.17 Data Sharing

7.1.18 Receiver

Click send

7.1.19 Data Sharing

7.1.20 Data Sharing

7.1.21 Data Sharing

7.1.22 Receive Details

7.1.23 View Decrypted Results

7.1.24 View Decrypted Results

7.1.25 View Decrypted Results

7.1.26 Algorithm Efficiency Calculation

7.1.27 Bar Chart

8. SOFTWARE TESTING

8.1 Testing and Implementation
In any of the project development testing is the crucial phase of the SLDC as it assures the enduser/client regarding the functionality of the code and it returns the results with data which ensures the user functionality either the logic is correct or wrong, there are various testing tools available in the industry for the testing purpose
In general testing is theprocess of identifying the correctness and quality of software program. The purpose is to check whether the software satisfies the specific requirements, needs and expectations of the customer. As such, testing is executing a framework or application with a specific end goal to discover programming bugs, imperfections or mistakes. The activity of testing is to discover the reasons of use disappointments with the goal that they can be revised by necessities.
There can be many reasons for defects in the software. The developer can also make an
error which may result in a defect or bug in the software source code. Any defect or bug
in the software will produce wrong results causing a failure. When a bug or defect causes
in software application, testing is done to find out the cause of defect and to remove the
bug.
Additionally, if a piece of programming creates bug, it must be redressed with the goal
that it doesn’t disturbs the entire procedure of programming program. That corrected part
is again tried to affirm that it is perfect with whatever is left of program.

8.2 Testing Methodology: Software can be tested with two ways.

Fig 6.2: Testing
a) Black Box Testing.
b) White Box Testing.

a) Black Box Testing: In this type of testing generally the tester has no idea of the internal working of the code/program which he was testing that approach is called black box testing and implementation knowledge is not required to be known for the black box testing.
This type of testing is applicable in most of the higher levels of testing tasks like user acceptance testing, system testing, general testing(done by the developer too) for the clarification purpose i.e it primarily focuses on the functionality of the system which is under test and software testing can be started based on the requirement specification documents. Some other type of testing includes in the black box testing are behavior testing,close box testing etc.

b) White Box Testing: In this type of testing methodology generally the tester needs to have the knowledge of the internal working program/code and knows how the system is being implemented and the tester needs to check the internal flow, data flow, exceptions, error handling, as some other coding standard practices.
Generally this type of testing is also being done by the developers too, to test the white box methodology programming knowledge is has to be carried out it includes the unit testing, integration testing etc so we can say that white box testing is meat for the structural test as it primarily concentrated on the testing of the program like code structure, conditions, loops etc.

8.2.1 Test cases
1 Login:
Number Test Case Field to be checked Expected
Output Actual Output Result
1 Blank Username Error message, Enter the Username Error message, Enter the Username Valid
2 Blank Password Error message, Enter the
Password Error message, Enter the
Password Valid
Table 6.2.2.1: Login
Test Case Id Step Description Expected Output Actual Output Result
01 Collect dataset from user. Using collect data ‘Button’ select a medical dataset txt file to be loaded into application. Should Load the Selected txt file. Pass.
02 Click “View Data” button without selecting the txt file. Shows Error Message “Please load a txt file”. Shows Error Message “Please load a txt file”. Pass.
03 Click “Next” button without selecting the txt file. Shows Error Message “Please load a txt file”. Shows Error Message “Please load a txt file”. Pass.
04 If we select a “Img” file instead of “txt” file. Shows Error Message “Please Select a valid txt file”. Shows Error Message “Please Select a valid txt file”. Pass.
05 If we select a empty
“txt” file. Shows Error Message “Invalid txt file”. Shows Error Message “Invalid txt file”. Pass.
2 Module(Collection):

8.3 Validation checking:
• Validation is done at the end of the development process and takes place after verifications are completed.
• It answers the question like: Am I building the right product?
• Am I accessing the right data (in terms of the data required to satisfy the requirement).
• It is a High level activity.
• Performed after a work item is created against set up criteria guaranteeing that the item incorporates effectively into nature.

• Determination of rightness of the last programming item by an improvement venture concerning the client needs and prerequisites.

Advantages of Validation
1. During confirmation if a few imperfections are missed then amid approval process it can be gotten as disappointments.
2. If during verification some specification is misunderstood, and development had happened then during validation process while executing that functionality the difference between the actual result and expected result can be understood.
• Validation is done toward the finish of the improvement procedure and happens after confirmations are finished. It answers the inquiry like: Am I assembling the correct item?
• Am I getting to the correct information (as far as the information required to fulfill the necessity).
• It is a High level movement.
• Performed after a work item is delivered against set up criteria guaranteeing that the item incorporates effectively into nature.
• Determination of accuracy of the last programming item by an improvement venture concerning t3. Validation is finished amid testing like component testing, joining testing, framework testing, stack testing, similarity testing, stretch testing, and so forth.

3. Validation aides in building the correct item according to the client’s prerequisite and aides in fulfilling their necessities. he client needs and prerequisites.

8.4 TESTING STATERGIES

The accompanying are the Testing Methodologies:
• Unit Testing.
• Integration Testing.
• Output Testing.
• Validation Testing.

UNIT TESTING
The objective of Unit Testing is to isolate a section of code and verify its correctness. In procedural programming a unit may be an individual function or procedure. Generally it is written and executed by the developers to make sure that the code meets the correct criteria and work as expected it is done in systematic way i.e it is segregates the each part of the program and test that the individual parts are working correctly that means the functions and procedures when we set for inputs then it should return the proper value it should the handle the failures correctly during the execution.
Unit testing is done generally before integration to ensure the valid input and output.

Integration Testing
It is also known as (I;T) which is done by the test engineer and integration testing starts after the unit testing and it falls in the black box testing module, so incorporation testing is the way toward testing to confirm that when at least two modules associate and the delivered result fulfills with its unique practical prerequisite or not, reconciliation testing distinguishes the bugs that may happen when at least two models get coordinated and they are executed according to the given necessity yet when they incorporated useful prerequisite and execution related issues will happen because of the combination.
In (I;T) there are three unique kinds of mix testing approach should be seen those are :
1. Big Bang- used to find the bugs when all the developed modules are interacted with each other and create a complete software system then its produced result satisfying with original requirement.
2. Top Down-Top level incorporated modules are tried first and its sub modules tried from best to down well ordered.
3. Base Up-All base (Sub Modules) level coordinated sub modules are tried first and its principle modules tried from base to up well ordered.

OUTPUT TESTING
The yield programming testing is a contribution to the QA procedure. The Quality Assurance process incorporates the whole business, and is utilized to drive the exercises (and measure the outcomes) that happen in the creation of the item.
So in general we can say that Output testing is an information about product quality.
the purpose of testing is to validate that the product meets the quality requirements.
That includes both functional (meeting customer requirements for features, usability, performance) and technical (crashes, data corruption, etc.) requirements.

VALIDATION TESTING
The way toward assessing programming amid or toward the finish of the improvement procedure to decide if it fulfills indicated prerequisites.
Approval testing is the way toward assessing the last item to check whether the product meets the client desires and prerequisites.It is a dynamic mechanism of validating and testing the actual product.
• Validation testing is a dynamic mechanism of validating and testing the actual product.
• Validation testing uses methods like black box (functional) testing, gray box testing, and white box (structural) testing etc.
• It always involves executing the code.

9. CONCLUSION

In the proposed system we have formalized the security model by providing the different types of attacks and ensured the security check for every model by following the re-encryption procedure in which a cipher text can be safely and restrictively shared among numerous authenticated users with ‘N’ number of records and sharing the data with security keys this data sharing is being performed for types of models that we have implemented in this project, Besides, this paper demonstrates that the new primitive is secure against picked ciphertext assaults in the standard model

9.1 FUTURE ENHANCEMENT

In multi sharing information we have seen multiple models for the cipher text we have used encryption and re-encryption methodologies to send the data to the authenticated user by using cryptographic keys and code word encrypted keys where every client keeps up their own particular cryptographic keys and the data sent from sender to end user in encrypted format by translation strategies
As the technology enhances with new type of servers and various types of attacks so this paper we have analyzed the severity of the choosen cipher text attack for a particular server further more we need to enhance the security models for various types of attack by other type of server and try to achieve the security to the sensitive information that is being leaked to new type of server attacks.
All stockpiling servers contain same information duplicate with them and there are chances that data leakage leads to data loss and loss revenue and loss of business so prevent this kind of issues in the future enhancement we strive to achieve more improved proxy re-encryption schemes with different types of applications to secure distributed storage for different use cases which distributed environment.

10.BIBLIOGRAPHY

References
1 G. Ateniese, K. Benson, and S. Hohenberger, “Key-private proxy re-encryption,” in Topics in Cryptology–CT-RSA (Lecture Notes in Computer Science), vol. 5473. Berlin, Germany: Springer-Verlag, 2009, pp. 279–294.

2 G. Ateniese, K. Fu, M. Green, and S. Hohenberger, “Improved proxy re-encryption schemes with applications to secure distributed storage,” in Network and Distributed System Security. Berlin, Germany: Springer-Verlag, 2005, pp. 29–43.

3 G. Ateniese, K. Fu, M. Green, and S. Hohenberger, “Improved proxy re-encryption schemes with applications to secure distributed storage,” ACM Trans. Inf. Syst. Secur., vol. 9, no. 1, pp. 1–30, 2006.

4 M. Bellare and S. Shoup, “Two-tier signatures, strongly unforgivable signatures, and Fiat–Shamir without random oracles,” in Public Key Cryptography (Lecture Notes in Computer Science), vol. 4450. Berlin, Germany: Springer-Verlag, 2007, pp. 201–216.

5 M. Blast, G. Bleumer, and M. Strauss, “Divertible conventions and nuclear intermediary cryptography,” in Advances in Cryptology. Berlin, Germany: Springer-Verlag, 1998, pp. 127– 144.