docs: Content updates.

content/learning/tls/ccm.md

@@ -23,6 +23,8 @@ learn_more:
 
 [CCM] mode is a block cipher mode that combines counter mode for confidentiality with cipher block chaining message authentication code (CBC-MAC) for authentication. It is designed for block ciphers with a 128-bit block length and requires careful nonce selection to avoid security vulnerabilities. CCM mode is used in various standards like IEEE 802.11i, IPsec, and TLS 1.2 for authenticated encryption.
 
+CCM modes of operation are slower than the (preferred) [GCM]({{% relref "GCM" %}}) modes.
+
 ## Information
 
 | Field        | Value                                                                             |

content/learning/tls/chacha20.md

@@ -0,0 +1,51 @@
+---
+title: ChaCha20
+description: ✅ Recommended encryption algorithm
+layout: learn-single
+
+tls_part: encryption-algo
+
+learn_more:
+  - text: 'The design of Chacha20'
+    url: https://loup-vaillant.fr/tutorials/chacha20-design
+
+  - text: 'ChaCha20-Poly1305 Cipher Suites for Transport Layer Security (TLS)'
+    url: https://datatracker.ietf.org/doc/html/rfc7905
+    source: IETF
+
+  - text: 'ChaCha20 and Poly1305 for IETF Protocols'
+    url: https://datatracker.ietf.org/doc/html/rfc8439
+    source: IETF
+
+  - text: 'RFC 7539-compliant implementation of the ChaCha20 stream cypher algorithm'
+    url: https://github.com/marcizhu/ChaCha20
+    source: GitHub
+
+  - text: 'ChaCha20-Poly1305'
+    url: https://en.wikipedia.org/wiki/ChaCha20-Poly1305
+    source: Wikipedia
+
+---
+
+## Summary
+
+[ChaCha20], a variant of [Salsa20], is a stream cipher utilizing add-rotate-XOR operations for security and efficiency. It offers a unique feature of efficiently seeking to any position in the key stream and has been adopted in various internet standards. Over _Salsa20_, it improves diffusion and performance, making it a more secure choice for cryptographic applications.
+
+> [!TIP]
+> This is a recommended algorithm.
+
+## Information
+
+| Field        | Value                                     |
+|--------------|-------------------------------------------|
+| Kind         | {{% param-kind %}}                        |
+| Invented     | 2008                                      |
+| Cracked      | -                                         |
+| Related tech | [Linux kernel], [OpenSSH], [QUIC], [SPDY] |
+
+[ChaCha20]: https://en.wikipedia.org/wiki/Salsa20#ChaCha_variant
+[Linux kernel]: https://lwn.net/Articles/686033/
+[OpenSSH]: https://en.wikipedia.org/wiki/OpenSSH
+[QUIC]: https://en.wikipedia.org/wiki/QUIC
+[Salsa20]: https://en.wikipedia.org/wiki/Salsa20
+[SPDY]: https://en.wikipedia.org/wiki/SPDY

content/learning/tls/idea.md

@@ -0,0 +1,26 @@
+---
+title: International Data Encryption Algorithm (IDEA)
+description: ❌ Vulnerable encryption algorithm
+layout: learn-single
+
+tls_part: encryption-algo
+
+---
+
+## Summary
+
+[IDEA], a symmetric-key block cipher, was designed as a replacement for [DES]({{% relref "DES" %}}).
+
+IDEA is slower and less secure than modern encryption algorithms. While IDEA was once considered secure, it has been broken using meet-in-the-middle and narrow-bicliques attacks, reducing its cryptographic strength.
+
+Any cipher suite with `IDEA` in the name should be avoided.
+
+## Information
+
+| Field    | Value              |
+|----------|--------------------|
+| Kind     | {{% param-kind %}} |
+| Invented | 1990               |
+| Cracked  | 2011               |
+
+[IDEA]: https://en.wikipedia.org/wiki/International_Data_Encryption_Algorithm

list.txt

@@ -1,6 +1,4 @@
 # Enc
-chacha20.md
-idea.md
 sm4.md
 
 # Hash