> For the complete documentation index, see [llms.txt](https://docs.editran.onesait.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.editran.onesait.com/documentacion-editran/ibm-editran-v5.3-cics-en/key-manager/introduction/observations-and-considerations-regarding-exchanges..md).

# Observations and considerations regarding exchanges.

The following observations can be made, each one a consequence of the others:

1. Encryption by exchanging RSA keys is more powerful than encryption by exchanging DES keys (RSA authentication)
2. Exchange key management requires having an RSA environment at both ends.
3. According to the above statements, it makes no sense to exchange DES keys through the Exchange Key Management application. That functionality is removed.

For example, if we generate V2 of subsystem S and do not send it to one of the remotes that we sent V1 to, nothing happens; that remote continues to work with V1. If we generate V3, and we do send it, the remote (and we) will have V1 and V3 active. In that situation, what could happen? Imagine that a remote is given V1 of subsystem S, and it never again exports new versions to it. However, you have created 99 versions of key pairs for subsystem S and have distributed them to other remotes that were also associated with that subsystem. When version 100 is created, the label containing V1 (and therefore its associated key) will be overwritten, so the remote that was only sent V1 will stop working.

Hence, it is very important to “properly size the subsystems depending on the needs of the installation”.

The subsystem we create locally does not have to have the same name as the subsystem created by the remote entity. We will decide the name of our local subsystem, and the remote entity will decide the name of its local subsystem. We will tell the remote entity ours (so that it creates it as a remote subsystem), and the remote entity will give us its local one so that we can create it as a remote subsystem.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## 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, and the optional `goal` query parameter:

```
GET https://docs.editran.onesait.com/documentacion-editran/ibm-editran-v5.3-cics-en/key-manager/introduction/observations-and-considerations-regarding-exchanges..md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

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.