Authentication Codes

2013 ◽  
pp. 155-190
Keyword(s):  
Author(s):  
Keith M. Martin

This chapter discusses cryptographic mechanisms for providing data integrity. We begin by identifying different levels of data integrity that can be provided. We then look in detail at hash functions, explaining the different security properties that they have, as well as presenting several different applications of a hash function. We then look at hash function design and illustrate this by discussing the hash function SHA-3. Next, we discuss message authentication codes (MACs), presenting a basic model and discussing basic properties. We compare two different MAC constructions, CBC-MAC and HMAC. Finally, we consider different ways of using MACs together with encryption. We focus on authenticated encryption modes, and illustrate these by describing Galois Counter mode.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Lina Zhang ◽  
Xuan Dang ◽  
Li Feng ◽  
Junhan Yang

Due to the widespread adoption and popularity of digital images in distributed storage, Secret Image Sharing (SIS) has attracted much attention. However, preventing the cheating of shares is an important problem that needs to be solved in the traditional SIS scheme. An adversary without image shares may participate in the restoration phase as a share owner. In this phase, the adversary can obtain real shares or prevent recovering real images by submitting fake shadows. Our schemes are based on the original Thien-Lin’s scheme. In the scheme I, we use some XOR operations to get two authentication codes through all secret pixel values to achieve a lightweight and fast-calculated authentication scheme for cheating prevention. This scheme is suitable for small devices with limited resources. In scheme II, we use a hash algorithm to generate the authentication code. This scheme is suitable for environments with larger storage space and higher security levels. Since all pixel values are involved in the authentication in our proposed schemes, it can prevent fake shadow images from cheating. Meanwhile, the shadow size is almost the same as the original Thien-Lin’s scheme. Experimental results and theoretical analysis show that the proposed schemes are feasible and effective.


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