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Mindblown: a blog about philosophy.

  • Popular Hash Functions

    Let us briefly see some popular hash functions − Message Digest (MD) MD5 was most popular and widely used hash function for quite some years. Secure Hash Function (SHA) Family of SHA comprise of four SHA algorithms; SHA-0, SHA-1, SHA-2, and SHA-3. Though from same family, there are structurally different. RIPEMD The RIPEMD is an…

  • Properties of Hash Functions

    In order to be an effective cryptographic tool, the hash function is desired to possess following properties − Design of Hashing Algorithms At the heart of a hashing is a mathematical function that operates on two fixed-size blocks of data to create a hash code. This hash function forms the part of the hashing algorithm.…

  • Cryptography Hash functions

    Hash functions are extremely useful and appear in almost all information security applications. A hash function is a mathematical function that converts a numerical input value into another compressed numerical value. The input to the hash function is of arbitrary length but output is always of fixed length. Values returned by a hash function are…

  • Data Integrity in Cryptography

    Until now, we discussed the use of symmetric and public key schemes to achieve the confidentiality of information. With this chapter, we begin our discussion on different cryptographic techniques designed to provide other security services. The focus of this chapter is on data integrity and cryptographic tools used to achieve the same. Threats to Data…

  • ElGamal Analysis

    In ElGamal system, each user has a private key x. and has three components of public key − prime modulus p, generator g, and public Y = gx mod p. The strength of the ElGamal is based on the difficulty of discrete logarithm problem. The secure key size is generally > 1024 bits. Today even 2048 bits long key…

  • Encryption and Decryption

    The generation of an ElGamal key pair is comparatively simpler than the equivalent process for RSA. But the encryption and decryption are slightly more complex than RSA. ElGamal Encryption Suppose sender wishes to send a plaintext to someone whose ElGamal public key is (p, g, y), then − C1 = gk mod p C2 =…

  • Example

    An example of generating RSA Key pair is given below. (For ease of understanding, the primes p & q taken here are small values. Practically, these values are very high). de = 29 × 5 = 145 = 1 mod 72 Encryption and Decryption Once the key pair has been generated, the process of encryption…

  • RSA Analysis

    The security of RSA depends on the strengths of two separate functions. The RSA cryptosystem is most popular public-key cryptosystem strength of which is based on the practical difficulty of factoring the very large numbers. If either of these two functions are proved non one-way, then RSA will be broken. In fact, if a technique…

  • RSA Cryptosystem

    This cryptosystem is one the initial system. It remains most employed cryptosystem even today. The system was invented by three scholars Ron Rivest, Adi Shamir, and Len Adleman and hence, it is termed as RSA cryptosystem. We will see two aspects of the RSA cryptosystem, firstly generation of key pair and secondly encryption-decryption algorithms. Generation of RSA Key Pair…

  • Public Key Encryption

    Public Key Cryptography Unlike symmetric key cryptography, we do not find historical use of public-key cryptography. It is a relatively new concept. Symmetric cryptography was well suited for organizations such as governments, military, and big financial corporations were involved in the classified communication. With the spread of more unsecure computer networks in last few decades,…

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