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book/source/03-cryptography.md
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@ -8,12 +8,12 @@ SPDX-License-Identifier: CC-BY-SA-4.0
## Cryptographic hash functions
[Cryptographic hash functions](https://en.wikipedia.org/wiki/Cryptographic_hash_function) take data strings of any length (like a text message or file) and output a fixed-size code, a "hash digest," which is often abbreviated as either "digest" or "hash." Hash digests are also sometimes called a "(cryptographic) checksum." A hash digest acts like a unique identifier for the original data.
[Cryptographic hash functions](https://en.wikipedia.org/wiki/Cryptographic_hash_function) take data strings of any length (like a text message or file) and output a fixed-size code, a "hash digest," which is often abbreviated as either "digest" or "hash." A hash digest is also sometimes called a "(cryptographic) checksum." A hash digest acts like a unique identifier for the original data.
Here are two important properties of cryptographic hash functions:
Cryptographic hash functions have two important properties:
- ["Pre-image resistance"](https://en.wikipedia.org/wiki/Preimage_attack): Given a hash digest, it should be very difficult to determine any data that matches this hash digest (including, but not limited to, the original data the hash represents). This property is related to acting as a [one-way function](https://en.wikipedia.org/wiki/One-way_function): a calculation that is easy to perform, but very hard to reverse.
- ["Collision resistance"](https://en.wikipedia.org/wiki/Collision_resistance): It should be very difficult to find two distinct pieces of data that map to the same hash digest.
- [**Pre-image resistance**](https://en.wikipedia.org/wiki/Preimage_attack): Given a hash digest, it should be very difficult to determine any data that matches this hash digest (including, but not limited to, the original data the hash represents). This property embodies the concept of a [one-way function](https://en.wikipedia.org/wiki/One-way_function) – a calculation that is easy to perform, but very hard to reverse.
- [**Collision resistance**](https://en.wikipedia.org/wiki/Collision_resistance): It should be very difficult to find two distinct pieces of data that map to the same hash digest.
## Message authentication codes
@ -95,9 +95,9 @@ Throughout this document, we will frequently reference asymmetric cryptographic
An asymmetric cryptographic key pair
```
Each key pair comprises two parts: the public key and the private key. For ease of identification, we will depict the public key in green and the private key in red throughout this document. Additionally, public keys are shown with a solid edge and pointing to the right, while private keys are shown with dotted edge and pointing to the left.
Each key pair comprises two parts: the public key and the private key. For ease of identification in this documentation, the public key will be shown in green and the private key in red. Additionally, public keys are depicted with a solid border and pointing to the right, while private keys are shown with a dotted border and pointing to the left.
It's important to note that in many scenarios, only the public key is exposed or used (we will expand on these situations in subsequent sections):
It's important to note that in many scenarios, only the public key is exposed or used. These situations will be elaborated upon in subsequent sections of this document.
```{figure} diag/public_key.png
---