fixed license reference, minor adjustments

Author: dghgit

CONTRIBUTING.md

@@ -15,15 +15,22 @@ Or you can [start a new discussion](../../discussions/new/choose) and ask your q
 
 If you find a problem with Bouncy Castle, [search if an issue already exists](../../issues).
 
-If a related discussion or issue doesn't exist, you can [open a new issue](../../issues/new). An issue can be converted into a discussion if regarded as one.
+If the issue is a potential security problem, please contact us at [email protected] before posting anything public.
+
+If a related discussion or issue doesn't exist, and the issue is not security related, you can [open a new issue](../../issues/new). An issue can be converted into a discussion if regarded as one.
 
 ### Contribute to the code
 
+For substantial, non-trivial contributions, you may be asked to sign a contributor assignment agreement. Optionally, you can also have your name and contact information listed in [Contributors](https://www.bouncycastle.org/contributors.html). 
+
+Please note we are unable to accept contributions which cannot be released under the [Bouncy Castle License](https://www.bouncycastle.org/licence.html). Issuing a pull request on our public github mirror is taken as agreement to issuing under the Bouncy Castle License.
+
 #### Create a pull request
 
-You are welcome to send patches, under the LGPLv2.1+ license, as pull requests. For more information, see [Creating a pull request](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/creating-a-pull-request). For minor updates, you can instead choose to create an issue with short snippets of code. See above.
+You are welcome to send patches, under the Bouncy Castle License, as pull requests. For more information, see [Creating a pull request](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/creating-a-pull-request). For minor updates, you can instead choose to create an issue with short snippets of code. See above.
 
-* Create a JUnit test case for your change, it may be a simple addition to an existing test. If you do not know how to do this, ask us and we will help you. 
+* For contributions touching multiple files try and split up the pull request, smaller changes are easier to review and test, as well as being less likely to run into merge issues.
+* Create a test cases for your change, it may be a simple addition to an existing test. If you do not know how to do this, ask us and we will help you. 
 * If you run into any merge issues, check out this [git tutorial](https://github.com/skills/resolve-merge-conflicts) to help you resolve merge conflicts and other issues.
 
 For more information, refer to the Bouncy Castle documentation on [Getting Started with Bouncy Castle](https://doc.primekey.com/bouncycastle/introduction#Introduction-GettingStartedwithBouncyCastle).
@@ -39,4 +46,3 @@ Don't forget to self-review. Please follow these simple guidelines:
 
 For acceptance, pull requests need to meet specific quality criteria, including tests for anything substantial. Someone on the Bouncy Castle core team will review the pull request when there is time, and let you know if something is missing or suggest improvements. If it is a useful and generic feature it will be integrated in Bouncy Castle to be available in a later release.
 
-For substantial, non-trivial contributions, you will be asked to sign a contributor assignment agreement. Optionally, you can also have your name and contact information listed in [Contributors](https://www.bouncycastle.org/contributors.html).