# Why is a raven

The script implements the SIDH key exchange scheme. If we look into more detail, it gives us a bit more information: ϕ\_A(P\_A).xy(), ϕ\_A(Q\_A).xy() the kernel of ϕ\_A is P\_A + Q\_A *k\_A, and so ϕ\_A(P\_A) + k\_A* ϕ\_A(Q\_A) = 0 this means we can solve for k\_A, and since the order of the subgroup is 2^216, discrete log is easy to do

sage go brrr or something i need to study this more


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://the-winrars.gitbook.io/writeups/2021-writeups/union-ctf/why-is-a-raven.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.