doc: Add initial 'Cryptography' section

[slyon]

Description

Add initial 'Cryptography' section do our "Security" documentation.

Also include some new tooling in tools/grep_cryptography.sh, to identify cryptography related terminology in our codebase.

FR-7556

Checklist

• Runs make check successfully.
• Retains code coverage (make check-coverage).
• New/changed keys in YAML format are documented.
• (Optional) Adds example YAML for new feature.
• (Optional) Closes an open bug in Launchpad.

[slyon]

@CodiumAI-Agent /review
--pr_reviewer.inline_code_comments=true
--pr_reviewer.require_score_review=true
--pr_reviewer.require_can_be_split_review=true
--pr_reviewer.require_soc2_ticket=true
--pr_reviewer.num_code_suggestions="2"

[CodiumAI-Agent]

PR Reviewer Guide 🔍

(Review updated until commit 4e21d25)

⏱️ Estimated effort to review: 2 🔵🔵⚪⚪⚪

🏅 Score: 85

🧪 No relevant tests

🔒 No security concerns identified

🔀 Multiple PR themes Sub-PR theme: Add tooling for identifying cryptographic terms Relevant files: tools/grep_cryptography.sh Sub-PR theme: Document cryptographic technologies and configurations Relevant files: doc/security.md

⚡ Key issues to review Possible Bug The comment correction from '265bit' to '256 bit' is good, but the actual regex pattern and logic for validating a WireGuard key might not be robust enough to ensure it's a valid key. Consider adding more rigorous checks or using a dedicated library for validation.

[daniloegea]

I left 2 comments in the text that we might want to address

[daniloegea]

Thanks, it looks good to me.

[CodiumAI-Agent]

Persistent review updated to latest commit 4e21d25