![Design
SHA-3 uses the sponge construction, in which data is "absorbed" into
the sponge, then the result is "squeezed" out. In the absorbing phase,
message blocks are XORed into a subset of the state, which is then
transformed as a whole using a permutation function f. In the "squeeze"
phase, output blocks are read from the same subset of the state,
alternated with the state transformation function f. The size of the part
of the state that is written and read is called the "rate" (denoted r), and
the size of the part that is untouched by input/output is called the
"capacity" (denoted c). The capacity determines the security of the
scheme. The maximum security level is half the capacity.
Given an input bit string M, a padding function {pad}, a permutation
function f that operates on bit blocks of width b, a rate r, and an output
length d, we have capacity c= b-r and the sponge construction
Z =sponge [ f, pad, r ] (M, d), yielding a bit string Z of length d](https://image.slidesharecdn.com/keccak-240113143709-42c8e9d8/85/keccak-ppt-that-is-about-introduction-and-basics-9-320.jpg)
keccak.ppt that is about introduction and basics
- 2. Title: SHA-3 Algorithm Presented by: soha khan
- 3. Cryptographic Hash Functions It is an algorithm that takes an input (often called a message) and returns a fixed-size string of bytes. The output, typically a ‘digest’, is unique (in theory) to each unique input. Even a tiny alteration to the input will produce a completely different output.
- 4. Properties of Hash function Deterministic: For a given input, the output (hash) will always be the same. Fast to compute: For any given data, the hash can be quickly computed. Irreversible: It should be computationally difficult to regenerate the original input value given the hash output. Collision-resistant: It should be computationally difficult to find two different inputs that produce the same output. Avalanche effect: A tiny change in the input should produce such a drastic change in output that the new hash appears uncorrelated with the old hash.
- 5. Background History The SHA-3 algorithm is also known as the Keccak algorithm The development of SHA-3 began as a response to vulnerabilities identified in earlier hash functions, including its predecessors like SHA-1 and SHA-2. In 2007, the U.S. National Institute of Standards and Technology (NIST) announced a public competition to develop a new cryptographic hash function. This competition drew a myriad of submissions from cryptographers worldwide. In 2012, the Keccak algorithm was selected as the winner, and by 2015, it was standardized and named SHA-3.
- 6. History ( Keccak Team) Bertone, Daemen, Peters, and Gill van was announced as the SHA-3 winner on October 2, 2012.
- 7. SHA-3 Introduction SHA-3 (Secure Hash Algorithm 3) is the latest member of the SHA family of standards, released by NIST on August 5, 2015. Unlike its predecessors (SHA-1 and SHA-2), SHA-3 uses the sponge construction, specifically the Keccak-f permutation, providing a different approach to processing data. SHA-3 supports variable output lengths of 224, 256, 384, or 512 bits, offering adaptability based on specific cryptographic requirements. Designed to address potential weaknesses in earlier hash functions, SHA-3 aims to provide a high level of security against various types of cryptographic attacks. The hash value is typically represented in hexadecimal form. A base-16 numerical system using digits 0-9 and letters A - F, where each digit represents four binary digits (bits).
- 8. SHA 3 variants You can select the desired SHA-3 variant based on the level of security and length of the hash value you need for your specific application. 1. SHA3-224: Produces a 224-bit hash value. 2. SHA3-256: Produces a 256-bit hash value. 3. SHA3-384: Produces a 384-bit hash value. 4. SHA3-512: Produces a 512-bit hash value.
- 9. Design SHA-3 uses the sponge construction, in which data is "absorbed" into the sponge, then the result is "squeezed" out. In the absorbing phase, message blocks are XORed into a subset of the state, which is then transformed as a whole using a permutation function f. In the "squeeze" phase, output blocks are read from the same subset of the state, alternated with the state transformation function f. The size of the part of the state that is written and read is called the "rate" (denoted r), and the size of the part that is untouched by input/output is called the "capacity" (denoted c). The capacity determines the security of the scheme. The maximum security level is half the capacity. Given an input bit string M, a padding function {pad}, a permutation function f that operates on bit blocks of width b, a rate r, and an output length d, we have capacity c= b-r and the sponge construction Z =sponge [ f, pad, r ] (M, d), yielding a bit string Z of length d
- 11. Diagram The sponge construction for hash functions. Pi are input, Zi are hashed output. The unused "capacity" c should be twice the desired resistance to collision or preimage attacks.
- 12. State Size we will look at how Keccak calculates the state size. b = 25 x 2ˡ; b = state size (where we have 5*5 of the block size of the state then we can have multiple Dimensions) value of l = {0, 1, 2, 3, 4, 5, 6} value of b = {25, 50, 100, 200, 400, 800, 1600} Rounds =12+2L