Doc: Simplify the "Decryption" doc

[yuxizama]

Hi team, During my review of documentation, I found the "Decryption" doc is particularly long and hard to read. I would suggest simply this document to improve readability for users. For example:

• Add section breaks
• Separate "function/steps explanations" and "parameter explanations", using bullet points instead of paragraphs Happy to provide further assistance if needed. 🙌 Thank you!