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Executive summary

Blind signature is the concept of cryptography that involves the usage of digital signature. The use of blind signature has been increasing on different privacy related protocols. This paper is based on the different aspects of blind signature. The will be focusing on the idea of blind signature in general that will be followed by the current working aspects and mechanisms of blind signature. The paper will be providing an insight on the different ideas and notions blind signature, which will be followed by the working and the techniques that used in order to ensure that the concept of blind signature is being utilised effectively. It has been noted that the usage of blind signature along with the mechanisms used in blind signature involves different issues. These issues are collectively identified in the given report. Providing an overview of bind signature concept in cryptography, the report gives an insight on the effectiveness and the major ways that can be used in order to resolve the issue that has been identified in terms of the overall usage of blind signature along with the workings of the concept and the techniques that are to be used in order to make the concept of blind signature more profound. The report then summarizes the overall discussion and the information gathered while attending the concepts of the given topic with a definite conclusion to the report enabling the identification of the motive of the report and the different aspects of blind signature to be visible. 

Overview of Blind Signature 

Blind signature is the concept present in cryptography, in which it has been identified and introduced by David Chaum, is a form of digital signature that involves the disguising the different contents of the messages that is to be signed beforehand. There is the involvement in the usage of the blind signature as it can be publicly verified against the original signature, which has not been processed through any form of cryptography techniques or concepts. The messages that are being blinded are carried out in the form of digital signature are carried out in the form of regular digital signature. The blind signatures that are being used are usually employed in the privacy related protocols. These protocols are the ones in which the signer and the message author are two different entities and do not match with each other. There are various usage of the blinded signature of the most common form of bind signature usage is the cryptographic election system and the digital cash schemes that are being used in the current technological world on a wider aspect (Thirumalai and Viswanathan, 2017). The schemes that have been implemented for the blind signature involve the usage of the common public key signing schemes for example, the use of the RSA and the DSA involves the concept of blind signature. It has been noted that the scheme of blind signature involves the blinding of the message that is to be sent in the form of a combination that will be processed in the way that contains the blinding factor. The blind signature is the schemes that are in use for different applications. These applications are the ones in which the privacy is the most important aspect that is to be maintained. There are various digital cash schemes and the voting protocols that involve the urging of the concept and the mechanism of blind signature (Zhu et al. 2017). 

Working mechanism of Blind Signature 

Blind signature as mentioned is the concept of that involves the process of signing a message without any previous knowledge of the whereabouts of the message and the information is being carried out by the message. The working of the blind signature is based on the idea of cryptographic the message to be sent or be signed. If an individual wants a message, A to be signed by another individual but intends to not reveal the message information to the other person that the concept of blind signature is being used. It has been noted that the concept is quite ambiguous and does not involve any prior motive. However, it has been analysed that the concept of blind signature is highly effective in terms of the involvement of anonymity, which will involve the usage of digital cash, and the process of voting based on electrical technology (Zhang and Jia, 2015). It has been noted that the concept of the blind signature works in an arrangement, which is given below:

• The first individual initially blinds the message A that is to be signed. The blinding of the message is carried out with the random number B. The number by which the message is to be blinded is known as the blinding factor. Combining the blinding factor  and the message the final outcomes turns out to be (A, B) 
• Once the other individual signs the message that has been blinded then the sign that is now generated is gathered as an output in the form of sign (blind (A, B) D). In this form the D private key for the other individual who has signed the message (Tian et al. 2016). 
• The message that is being received after the other individual has carried out the signing of the message is then un-blinded by the first individual who has sent the blinded message. The unwinding of the message is carried out with the help of B. The message which is thus, received is in the form un-blind (sign(blind(A,B)D)B).
• It has been noted that the functions that are being sued in order to conduct the activity of blinding the messages and vice versa involves the design that helps in the reduction of the message to the form sign(A,B) which is the signature that has been given by the other individual on the given message A (Islam et al. 2016).

The given steps that has been set out above is involved in the working of the blind signature that allows individuals to sign different messages without revealing the content of the message and keeping the confidentiality of the message to be signed intact. 

Techniques involved in Blind Signature 

The technique that involves in the usage of the blind signature includes different schemes. The first schemes of blind signature are based on the RSA signature scheme. It has been presented below:

The original RSA Scheme of blind signature

These schemes involve different aspects of the techniques that are being used in terms of the algorithm used in the concept of RSA. It is based on the concept of public key and private key. For example, if there were two numbers, which are primes relatively, then the common factor would be 1. According to the concept of Euler’s totient it has been noted that the number N as written in the form phi(N) is the total number of relative primes that are following N. This concept is effective because the number N is prime number itself. So this shows that the answer for the given outcome would be phi(N)= N-1. This technical process is being used in terms of maintaining the overall system of conducting blind signature (Chen et al.2017). 

Modulo arithmetic

Modulo arithmetic is the system that involves logical process of arithmetic for the integers and the concept in which the numbers are wrapped around until it is reaching a certain value, which involves modulus. It is important to note that use of modulo arithmetic has been involved for the process of conducting the cryptographic aspects in the blind signature process due to the number reduction process that is present in the given structure of modulo arithmetic. The modulo arithmetic concept is used in the process of blind signature in the form of mod that is present in the given arithmetic concept. It is important to note than the concept defines the reduction of all the numbers into their remainder on division by the number N. 

Generation of the public and private keys

In terms of generating the private and the public keys, it has been realised that there is the requirement for selecting two prime number, which will be multiplied in order to get a number. This number is termed to be the bit number. After the selection of the prime numbers, there is the need to maintain a relatively prime number that will be helping the Euclid’s algorithm to be applied in the entire process of encryption and decryption (Fan et al. 2016). The number that is being obtained from the use of the Euclid’s algorithm is the pair of numbers, which will involve the private key and the public key as well for hiding the original message to be signed and then retrieving the message that has been signed. This indicates retrieving the signature that has been carried out.    

Message format

On terms of the format of the message, the messages that are to be signed are divided into different blocks. These blocks help in attaining the correspondence to a number, which is less than N. It is important to note that the use of a binary number, the blocks will be in the form of log bits. This format helps the individuals as in the receiver and the signer to gain the message effectively without any intrusion of any third party. The signing format that is to be maintained in the process of the blind signature involves the use of the message in the form of  s=m d mod n. In order to verify the signature that has been obtained, the recovery of the message is carried out from the signature s, where the m is being put in the mod n format. This process helps on the verification that the signature that has been done is properly carried out or not (Guo et al.2016). 

Pros and Cons of Blind Signature 

The use of blind signature has different advantages and disadvantages based on the usage of the system. It has been analysed that the concept of blind signature is highly effective in maintaining confidential signatures that are not applicable to be read or manipulated by any other person. Even the individual carrying out the signing process is not being disclosed with the contents of the message that is to be signed. It has been analysed that different aspect in which the concept of blind signature is being used. In terms of electronic voting system and cash payment, the concept of blind signature has been used so that any means or any other third party does not focus on the signature that is to be carried out. It is important to note that the voting system in the current times involves electronic voting. The use of the bind signature enables the voters to provide a fair vote to the required individual. This also shows that there is effectiveness in terms of hiding the content as in the name of the individual for whom the vote has been given (Alam et al. 2016). This further allows the process of voting to fair and there will be less threat in terms of cheating or any other activity during the process of voting.  

On the other hand, the blind signature process is also used in the system of cash payment that is conducted online. The system is highly benefited by the use of the online signature as it helps the individual user to maintain the authenticity of the signature. It allows the individuals restricting themselves from being caught into theft or any kind of fraud, which is possible using the manual signing process. The blind signature process will not allow the revealing of the message content as in the signature that is being sent so that there is no copying of the signature in future. Thus, providing an effective and safe way of conducting cash payments over internet (Singh et al. 2015).

Despite of the positive aspects of the blind signature process, there are certain negative aspects, which is important to be considered while conducting the use of the blind signature. It is important to note that the security is the major concern when it comes to defining the cons of the blind signature process. The concept of blinding attack is the major concern when it comes to the risks if using such technique in future or in any other field or activity. It is highly important to note that there are various aspects, which is essential to be maintained in terms of using the blinding signature. The basic misuse is the attack that might be received from an intruder due to the ineffective of the security means that has been used to encrypt the message to be signed. It is highly important to vote understand that there are different methods and ways in which the cyber criminals will be able to identify the loopholes in the public key and the private key that has been used to encrypt and decrypt the message, which will be allowing the illegal changes that can be made in the message and then send the message to the sender without any scope of noticing the change that has been made (Gomes et al. 2017).

Challenges of Blind Signature 

The using of any new system of technology allows various positive aspects and effectiveness. However, it has been noted that despite of the effectiveness being given by the new system, there are certain challenges that are to be faced by the individuals using the system and the system itself. One of the most important challenges that are to be faced by the use of the blind signature process is the security challenge (Saxena et al. 2017). The use of the blind signature has been active in every aspect of online documentation process that is usually carried out in the recent times. It is important to note that the different activities which are related to the maintaining of the security of the blind signature system. It is important to note that the verification process involves consent of the signer, which is highly time consuming. It has been analysed that the payment process that are carried out using the bind signature process involves higher risks in terms of the attackers who might find out ways to encrypt the message that is to be signed on along with the signature. This will help them to conduct fraud and theft by misusing the obtained information for their better needs and benefits. There can be the conduction of illegal money transfer, which will be causing harm to the one conducting the payment. During the process of conducting any cash withdrawal there can be ineffective usage of the system and fraud being used to the customer of the bank in which the process of withdrawal is being conducted (Petzoldt et al. 2017).   

Issues in Blind Signature technique

There are different issues, which are both theoretical and practical in terms of the usage of the blind signature process. Some of the theoretical issues that are present in the usage of the blind signature process are given as follows:

Theoretical issues

The different theoretical issues that are being faced by the use of the blind signature process involve the process of identifying each other. There is the process of generating a sequence, which will allow the multiplying of the factor that has been generated randomly. It is highly important to note that there are different results that are being sent using the public key intact leading to misuse of the key. The message that seeing received is done by using the secret key. 

It has been noted while conducting the activity of adding up a cash customer in the bank account with the help of the blind signature there are certain aspects, which are important to be maintained else there will be the conduction of different issues in it. There is the need to send a message that would be obtained from B and will be sent back to B. This is the concept of pre-encrypting the message with a public key. There will be the requirement of convincing that the coin has not been used or paid (Castiglione et al. 2016).  

Some of the other theoretical issues that are to be faced are morphism of the signature scheme. This is the schemes, which will involve the use of the computable mapping in the form of message-signature pair. This is the concept that will be allowing the creation of the base pairs that will be going through the process of signature verification effectively. 

Practical issues

 Considering the different protocols that are present in the process of cryptography, it has been noted that there are three types of issues when the practical issues are being counted for the usage of the blind signature process. Some of them are given as follows: 

Partially blind signature: there is the need to conduct compulsory registration, which will be used in electronicon system. This is one of the major drawbacks of the blind signature system. There is the need to maintain their own database, which is of higher volume. It is important to note that this is the process that to be increased as the number of coins. There is the vulnerability in terms of getting an attack on the morphism signature schemes. It is important to note that there will be the inability to determine the coin that is to be sent to the user to sign.

Security of blind signature: there will be the presence of invulnerability f the random parameters that will be creating the inability to gather the different information of the encryption mask and the values. There will be the inability to produce the correct electronic signature by any individual other than the bank. There will be the presence of the property, which will be guaranteeing the variables in terms of signing the authority and receiving the protocol development. This will further result in the signatures that are statistically independent. There will be the inability to gather the identification of the data about the different users, which is to be provided in the message signature. 

Blind signature on elliptic curves: there is the group presence, which involves the calculation of the order, which is possible in any polynomial times. It is important to note that despite of the polynomial time presence there is the affectivity of the tasks in terms of calculating the order in which the complexity of the problem in terms of factoring the composite number is being faced (Fan, 2016). 

Recommendation to reduce the issues 

It is to be recommended that the different issues that are to be faced by the use of the blind signature process involve the technical and the algorithmic aspects of the system. It is highly recommended that algorithms to be used in order to conduct the process of blind signature must involves different creation that will involve the use of less time in terms of receiving the encrypted signature message and then sending it back to the sender again. This will further help the process of using the banking system with the help of blind signature more convenient for the users. There is the need to maintain the change as per the needs of the customers based on the field in which this system acne be used effectively without any fail. It is highly effective and recommended that the companies using such system needs to be active in terms of gaining the overall aspects of the blind signature system features. This will help in the further identification of the flaws and the loopholes, which can be removed making the blind signature system more profound and valuable for the company. The involvement the companies will also help in the identification of the different features that can be added in the system in order to make the system more effective for commercial use and other purposes considering the newly added features of the system and the changes to be made.  

Conclusion 

Thus, from the given discussion it can be concluded that the use of the blind signature process involves different aspects, which are important to be considered in terms of developing the system further. It has been analyzed that the blind signature system is highly efficient in maintaining the confidentiality of different messages that is to be signed without letting the individual know about the content that is present in the message. The use of the blind signature system will be affecting the overall process of documentation carried out online as the process of documentation involves the use of the signature that are important to be maintained. In such cases when online documentation is carried out the blind signature is highly effective, despite of the different difficulties and issues that might be faced due to the use of the system. It is important to note that the different activities that are to be carried out in order to mitigate the loopholes of the blind signature system involve the use of the algorithmic changes for better usability of the system. Thus, showing the pros and cons of using the blind signature concept or system in different aspects.