A-Z Popular Blog Security Search »
Information Security
Related Guides
Related Topics

What is a Hashcode?

 , updated on October 20, 2016
A hashcode is a fixed length code that may be used to verify data integrity, authenticate messages or look up resources. Hashcodes are also a fundamental aspect of encryption. For example, passwords are typically stored as hashcodes.
A class of algorithms known as a hash function can be used to create fixed-length hashcodes from messages of any length. Ideally, these algorithms have several unique properties:
Non-Reversible - It is impossible generate a message from its hashcode. Hash functions are known as trap doors because they only go one way from message->hashcode and not the reverse.
Avalanche Effect - A small change in a message leads to large change in the hashcode. This is known as the avalanche effect.
Hash Collision - It is exceedingly unlikely that two messages will generate the same hashcode. When this does happen, it is known as hash collision.


A software download that is 3 megabytes in size is distributed with a 128 bit hash code. Anyone who downloads the software can use a freely available hashcode tool to confirm the download. The smallest change to the software will generate a completely different hashcode.
An instant messaging app uses a hashcode to confirm that messages haven't been tampered with in transit.
A programming language uses hashcodes of objects to identify instances.
An encryption tool stores hashcodes of passwords as opposed to the passwords themselves. If the hashcodes are compromised, the passwords will remain confidential.
Definition (1)
A fixed length code generated from a message for purposes such as data and message verification.
Definition (2)
A fixed length code that represents a binary source of any length. Hash codes are ideally non-reversible and sensitive with small changes in source leading to completely different hashcodes.
A type of identifier commonly used in data verification, message authentication, encryption and data structures.
The algorithms used to create hashcodes, known as hashing functions differ widely in strength. Algorithms that are considered strong enough for encryption are known as cryptographic hash functions. Hashcodes and hashing should not be confused with encryption as they are simply one of many components that go into building an encryption tool.
Related Concepts

Information Security

This is the complete list of articles we have written about information security.
Audit Trail
Canary Trap
Critical Infrastructure
Cryptographic Keys
Cryptographic Salt
Cybersecurity Risk
Data Breach
Data Remanence
Data Room
Data Security
Deep Magic
Defense In Depth
Digital Identity
Failure Of Imagination
Incident Response
IoT Security
Key Stretching
Network Security
Operations Security
Overlay Network
Password Entropy
Password Fatigue
Proof Of Work
Secure Code Review
Security As A Service
Security Controls
More ...
If you enjoyed this page, please consider bookmarking Simplicable.

Security vs Privacy

The relationship between security and privacy.


An overview of technology hardening.

Deep Magic

An overview of deep magic, a technology term.

Defense In Depth

An overview of defense In depth.

Encryption Examples

A definition of encryption with examples.

Canary Trap

A definition of canary trap with an example.


A definition of honeypot with examples.

Security Through Obscurity

A definition of security through obscurity with an example.


A definition of token with examples.


A definition of backdoor with examples.

Privacy By Design

An overview of privacy by design.

Expectation Of Privacy

The definition of expectation of privacy.

Personally Identifiable Information

An overview of personally identifiable information.

Delete vs Wipe

The difference between deleting data and wiping it.

Data Risks

A definition of data risk with examples.

Personal Information

A definition of personal information with examples.

Data Subject

A definition of data subject with examples.

Machine Readable

The definition of machine readable with examples.


The definition of delete with examples.

Privacy Examples

The definition of privacy with examples.
The most popular articles on Simplicable in the past day.

New Articles

Recent posts or updates on Simplicable.
Site Map