S/MIME ECDSA 384 support

Originally posted by frenzybiscuit February 23, 2026

Issue Description

When trying to upload the ECDSA 384 key in Stalwart, it will not save the certificate.

RSA 4096 works.

Expected Behavior

works as expected

Actual Behavior

doesn't work

Reproduction Steps

ssl.com and generate a ECDSA SMIME 384.

Relevant Log Output

No response

Stalwart Version

v0.15.x

Installation Method

Binary (Linux)

Database Backend

PostgreSQL

Blob Storage

PostgreSQL

Search Engine

PostgreSQL

Directory Backend

Internal

Additional Context

No response

I acknowledge that:

• I have reviewed the documentation and FAQ and confirm that my issue is NOT addressed there.
• I have searched the Stalwart repository (both open and closed Discussions and Issues) and confirm this is not a duplicate.
• I have set the logging level to trace and included relevant log output if applicable.
• I agree to follow the project's Code of Conduct.