Hash Function Software Security

1. Hash Functions in Software Security
What is a Hash Function?
Hash Function is like a mathematical function that has a huge role in making a
System Secure as it converts normal data given to it as an irregular value of
fixed length. We can imagine it to be a Shaker in our homes.
When we put data into this function it outputs an irregular value. The Irregular
value it outputs is known as “Hash Value”.Hash Values are simply numbers
but are often written in Hexadecimal. Computers manage values as Binary. The
hash value is also data and is often managed in Binary. Simple Hash value

2. Little complex hash value
Difference in Hash Value

3. Guessing is Difficult
That is why it is considered more secure than encryption and decryption.
Common Hash Algorithms
Several cryptographic hash functions are widely used in security
applications:
• MD5 (Message Digest Algorithm 5) o Produces a 128-bit
hash value.
o Considered insecure due to vulnerabilities allowing collisions.
• SHA-1 (Secure Hash Algorithm 1) o Produces a 160-bit
hash value.
o No longer considered secure due to successful collision attacks.
• SHA-2 (Secure Hash Algorithm 2) o Includes SHA-224,
SHA-256, SHA-384, and SHA-512.
o Offers stronger security than MD5 and SHA-1.
• SHA-3 (Keccak Algorithm) o Designed as a successor to
SHA-2 with enhanced security and resistance to attacks.

4. • BLAKE2 & BLAKE3 o Optimized for speed and security,
providing better performance than SHA-3.
Applications of Hash Functions in Security
1. Password Security – Websites don’t store your actual password. Instead, they
convert it into a hash (a unique code). When you log in, the system checks if
the hash matches, keeping your password safe from hackers.
2. File Integrity Checking – When you download software or files, websites
often provide a hash value. You can compare it with your file’s hash to ensure
it hasn’t been tampered with.
3. Digital Signatures & Website Security (SSL/TLS) – Hash functions help
verify the authenticity of emails, documents, and websites. This ensures that
data hasn’t been altered and comes from a trusted source.
4. Blockchain & Cryptocurrencies – Bitcoin and other cryptocurrencies use
hash functions to secure transactions. Each block in the blockchain has a hash,
making it nearly impossible to change past records.
5. Secure Communication (HMAC) – Online banking and secure messaging
apps use hash functions to check if messages have been altered during
transmission.
6. Antivirus & Malware Detection – Antivirus programs store hash values of
known viruses. If a new file matches one of these hashes, it is flagged as a
threat.
7. Electronic Voting Systems: Hash functions ensure that votes remain secure
and tamper-proof.
Example: Some electronic voting systems use hash functions to secure ballots and
prevent vote manipulation.
Hash Function Attacks
• Collision Attack – When two different inputs produce the same hash, leading
to security vulnerabilities.
• Birthday Attack – A special type of collision attack exploiting the probability
of finding two inputs with the same hash.

5. • Pre-image Attack – Attempting to reverse-engineer the input from its hash.
• Rainbow Table Attack – Using precomputed hash values to quickly find a
matching password, countered by salting (adding a random string to
passwords before hashing).
Hash Functions in System Security
Hash functions play a significant role in securing systems by converting
normal data into an irregular value of fixed length. We can imagine a hash
function as a "shaker" that processes input data and generates a unique
hash value. These values are numbers typically represented in
hexadecimal and managed in binary by computers.
Features of Hash Functions in System Security:
• One-way function – It is computationally infeasible to reverse-engineer the
original input from the hash.
• Deterministic – The same input always produces the same hash output.
• Fixed-size output – Regardless of input size, the output remains fixed.
• Collision resistance – It is difficult to find two inputs that produce the same
hash.
• Non-reversible – The hash function does not allow retrieval of the original
input from its hash value.
Advantages of Hash Functions
• Data Integrity – Ensures that any modification to the original data will change
the hash value, making it a useful tool for detecting data tampering.
• Message Authentication – Useful for verifying the authenticity of messages,
ensuring that they have not been altered.
• Password Storage – Enhances security by preventing direct retrieval of
passwords.
• Fast Computation – Efficiently computes hashes, making it suitable for
various applications.

6. Disadvantages of Hash Functions
• Collision Attacks – An attacker may find two different inputs that produce
the same hash, compromising security.
• Rainbow Table Attacks – Precomputed tables of hash values make it easier
to crack password hashes.
• Weaknesses in Some Algorithms – Older hash functions like MD5 and SHA1
are vulnerable to attacks.
• Limited Input Size – Since hash outputs are of fixed length, large datasets
may lead to collisions.
In short, Hash functions are important in modern cybersecurity,
from authentication to data integrity and blockchain security.
However, selecting a secure hash function is critical to prevent
vulnerabilities. Algorithms like SHA-3, BLAKE3, and Argon2 are
currently among the most secure choices for cryptographic
applications.