Hash function

Q: How deeply does Acing the CCNA Exam: Volume 2 Advanced Networking and Security cover hash function?

Defines one-way fixed-length conversion and contrasts password storage options, but does not explain algorithm internals.

As explained in Acing the CCNA Exam: Volume 2 Advanced Networking and Security

A hashing algorithm transforms input data into a fixed-size digest that can support password protection and integrity verification.

A hash function converts input data such as a password into a fixed-length digest that cannot be reverted to the original input. Hashing is one-way, unlike reversible encryption. section 11.3.1

For Cisco IOS password protection, store enable secrets as hashes rather than cleartext or weak reversible encryption. Type 0 enable passwords expose cleartext, while type 7 passwords remain easily decryptable. section 11.3.1

Use enable secret instead of enable password. IOS supports multiple hashing algorithms; the available algorithms depend on the device model and IOS version, and an unspecified algorithm uses the device default. section 11.3.1

Hash an enable secret with scrypt

SW1(config)# enable algorithm-type scrypt secret CiscoCCNA SW1(config)# do show running-config | include enable enable secret 9 $9$h.p1X8KVxbaILq$pNEykQjoAJbKCYfmBL9Hq8yPU/EqDGpoBkCIZ.s9GJA The saved value is a hash, and the leading algorithm indicator identifies scrypt.

How Acing the CCNA Exam: Volume 2 Advanced Networking and Security covers it

Cover of Acing the CCNA Exam: Volume 2 Advanced Networking and Security

liveBook manning.com

Read Acing the CCNA Exam: Volume 2 Advanced Networking and Security on liveBook Get the book at manning.com

Also explained in

liveBook manning.com

Real-World CryptographyA hash function maps input data to a fixed-size output and may provide cryptographic properties such as one-wayness and collision resistance.
liveBook manning.com

Hacking CryptographyA function that maps input data to a fixed-size digest, typically designed so that recovering or finding inputs with specified relationships is computationally infeasible.
liveBook manning.com

Grokking Algorithms, Second EditionA hash function is a deterministic function that maps a key to a value used to determine its storage location in a hash table.
liveBook manning.com

Grokking Data StructuresA hash function is a function that maps input data to a bounded hash value used to compute or organize lookup keys.
liveBook manning.com

Spring Security in Action, Second EditionA hashing algorithm deterministically transforms input data into an output from which the original input is intended to be impractical to recover.
liveBook manning.com

Troubleshooting Java, Second EditionHashing is the transformation of data into a fixed-size digest that can be compared to detect content differences without transmitting the original data.
liveBook manning.com

Grokking Relational Database DesignA hash function is a function that maps variable-length input data to a fixed-length output value.
liveBook manning.com

The Joy of JavaScriptThe process of computing a fixed-size digest or hash value from input data using a hash function.
liveBook manning.com

First-Party Data ActivationThe transformation of input data into a fixed-length value designed for integrity checking, lookup, or comparison without retaining the original representation.
liveBook manning.com

Effective Data AnalysisA hash algorithm is a computational procedure that deterministically maps data to a fixed-size hash code.
liveBook manning.com

Grokking Web Application SecurityA hashing algorithm deterministically maps input data to a fixed-size hash value while being designed to make different inputs produce different values with high probability.
liveBook manning.com

Python How-ToHashing is the computation of a compact hash value from input data using a hash function.
liveBook manning.com

ASP.NET Core in Action, 3eA hash is a deterministic compact value computed from data such that modifying the data normally changes the resulting value.
liveBook manning.com

Akka in Action, Second EditionA hashing algorithm is an algorithm that deterministically maps input data to hash values.
liveBook manning.com

Python Workout, Second EditionA hash function is a function that maps a hashable Python object to an integer hash value used by hash-based data structures.

Compare how 16 books explain hash function →

Related concepts

hash valueproduces · A hash value is a deterministic, typically fixed-size value produced by applying a hash function to input data, often for lookup, comparison, identification, or integrity checking.
SHA-256includes · SHA-256 is a standardized cryptographic hash function in the SHA-2 family that maps arbitrary input data to a fixed-length 256-bit digest.
cryptographic hashproduces · A cryptographic hash is a fixed-length digest computed from input data by a deterministic function designed to resist preimage, second-preimage, and collision attacks.
bloom filterused by · A Bloom filter is a space-efficient probabilistic data structure for testing set membership that permits false positives but not false negatives.
SHA-2includes · SHA-2 is a standardized family of cryptographic hash algorithms that produces fixed-length digests, including SHA-224, SHA-256, SHA-384, and SHA-512.
HMACused by · HMAC is a keyed message authentication code constructed from a cryptographic hash function and a secret key to authenticate data and verify its integrity.

This explainer was generated by Manning's knowledge graph from the text of Acing the CCNA Exam: Volume 2 Advanced Networking and Security. The section links point to the parts of the book it draws on.