Secure Hash Algorithm with the acronym SHA is a cryptographic hash function used to hash a text signature or hash certificate

1. AKENTEN APPIAH- MENKAH UNIVERSITY OF SKILL TRAINING AND ENTREPRENEURIAL DEVELOPMENT
SECURE HASH FUNCTIONS
IN
INFORMATION SECURITY
BY
MILLICENTIA PRINCE DUAH MENSAH CALEB

2. AKENTEN APPIAH- MENKAH UNIVERSITY OF SKILL TRAINING AND ENTREPRENEURIAL DEVELOPMENT
What are Secure Hash Functions?
 Secure Hash Functions, with the acronym SHA, are a family of
cryptographic hash functions used to create text signature or hash data
and certificates.
 Secure Hash Functions take an input of 20 bytes (160 bits) long
maximum and returns a 40- digit hexadecimal hash value as its output.
 The smallest changes in the input can make a big difference in the coded
text output. The phenomenon is called the Avalanche Effect

3. AKENTEN APPIAH- MENKAH UNIVERSITY OF SKILL TRAINING AND ENTREPRENEURIAL DEVELOPMENT
Figure 1: Shows the Basic Concept of Secure Hash Functions

4. AKENTEN APPIAH- MENKAH UNIVERSITY OF SKILL TRAINING AND ENTREPRENEURIAL DEVELOPMENT
Characteristics of Secure Hash Functions
 They have variable input length and fixed output length
 The are one- way functions
 If the same input message is fed to the Secure Hash Function, it will
generate the same resultant hash.
 It is not possible to generate the same hash value using two different
input values. This is called Collision Resistance

5. AKENTEN APPIAH- MENKAH UNIVERSITY OF SKILL TRAINING AND ENTREPRENEURIAL DEVELOPMEMENT
Types of Secure Hash Functions
Some of the Secure Hash Functions currently in use are:
 Secure Hash Algorithm (SHA)- 1
 Secure Hash Algorithm (SHA)- 2
 Secure Hash Algorithm (SHA)- 3
Because Secure Hash Algorithm- 1 is being phased out and is not recommended for
any new designs, this application note only discusses SHA- 2 and SHA- 3

6. AKENTEN APPIAH- MENKAH UNIVERSITY OF SKILL TRAINING AND ENTREPRENEURIAL DEVELOPMENT
SECURE HASH ALGORITHM (SHA)- 2
The SHA- 2 function has four main types based on output bit lengths as
follows:
 SHA-224 – hash is 224 bits long
 SHA-256 – hash is 256 bits long
 SHA-384 – hash is 384 bits long
 SHA-512 – hash is 512 bits long

7. AKENTEN APPIAH- MENKAH UNIVERSITY OF SKILL TRAINING AND ENTREPRENEURIAL DEVELOPMENT
Figure 2: Secure Hash Algorithm (SHA)- 2
(SHA-256 – hash generation flow)
The input message is first padded to make sure that it will completely fit in “n” number of
512-bit blocks.

8. AKENTEN APPIAH- MENKAH UNIVERSITY OF SKILL TRAINING AND ENTREPRENEURIAL DEVELOPMENT
SECURE HASH ALGORITHM (SHA)- 3
The SHA-3 function has no predefined output length. The input and output lengths have no
maximums either. For comparison purposes with SHA-2, we can define four main types
based on output bit lengths:
 SHA3-224 – hash is 224 bits long
 SHA3-256 – hash is 256 bits long
 SHA3-384 – hash is 384 bits long
 SHA3-512 – hash is 512 bits long

9. AKENTEN APPIAH- MENKAH UNIVERSITY OF SKILL TRAINING AND ENTREPRENEURIAL DEVELOPMENT
Figure 3: Secure Hash Algorithm- 3 (SHA3-256 – Keccak sponge hash generation flow)