Move certificates into per-test directories

Each secure test now has its own certs/ subfolder with per-identity
subdirectories and a single shared trust store.  Configs reference
paths relative to the project root (e.g. tests/secure_anonymous/
certs/ServerLDS/cert.der).  Cert generation logic removed from test
scripts since certs are now pre-generated and committed.

1 files changed, 14 insertions, 43 deletions

diff --git a/readme.md b/readme.md
index f6a7916..bc5d4c0 100644
--- a/readme.md
+++ b/readme.md
@@ -5,7 +5,7 @@ A small C project that demonstrates OPC UA server discovery using the
 
 - **ServerLDS** — Local Discovery Server that other servers register with
 - **ServerRegister** — a server that periodically registers itself with the LDS
-- **Client** — queries the LDS for servers, lists endpoints, or reads the current time from a server
+- **Client** — queries the LDS for servers, lists endpoints, reads the current time, or downloads a server's certificate
 
 ## Prerequisites
 
@@ -23,52 +23,19 @@ git clone --recursive https://git.tvcloud.fr/opcua_c
 cd opcua_c
 ```
 
-### Generate certificates
+### Certificates
 
-The programs use TLS certificates for mutual authentication. ServerLDS and
-ServerRegister can also run without certificates (SecurityPolicy#None only) by
+Test certificates are pre-generated and committed under each test directory
+(e.g. `tests/secure_anonymous/certs/`). Each secure test has per-identity
+subdirectories (`ServerLDS/`, `ServerRegister/`, `ServerRegisterClient/`,
+`Client/`) containing `cert.der` and `key.der`, plus a shared `trust/`
+directory with all certificates.
+
+Programs can also run without certificates (SecurityPolicy#None only) by
 omitting the `certificate`, `privateKey`, and `trustStore` keys from their
 config files.
 
-For encrypted operation, four identities are needed. Each call to
-`tools/generate_certificate.sh` creates a self-signed RSA-2048 certificate
-(`<name>_cert.der`) and private key (`<name>_key.der`) in the given directory:
-
-```sh
-tools/generate_certificate.sh certs ServerLDS
-tools/generate_certificate.sh certs ServerRegister
-tools/generate_certificate.sh certs ServerRegisterClient
-tools/generate_certificate.sh certs Client
-```
-
-| Identity | Used by | Purpose |
-|----------|---------|---------|
-| `ServerLDS` | ServerLDS | Server certificate for the LDS |
-| `ServerRegister` | ServerRegister | Server certificate for the registering server |
-| `ServerRegisterClient` | ServerRegister | Client certificate used when connecting to the LDS |
-| `Client` | Client | Client certificate for all client operations |
-
-### Populate the trust stores
-
-OPC UA applications only accept connections from peers whose certificate is in
-their trust store. Create the trust store directories and symlink each peer's
-certificate:
-
-```sh
-mkdir -p certs/trust/{server_lds,server_register,server_register_client,client}
-
-ln -s ../../ServerRegisterClient_cert.der ../../Client_cert.der \
-   certs/trust/server_lds/
-
-ln -s ../../ServerLDS_cert.der ../../Client_cert.der \
-   certs/trust/server_register/
-
-ln -s ../../ServerLDS_cert.der \
-   certs/trust/server_register_client/
-
-ln -s ../../ServerLDS_cert.der ../../ServerRegister_cert.der \
-   certs/trust/client/
-```
+To generate new certificates, use `tools/generate_certificate.sh <output_dir> <name> [uri]`.
 
 ### Build
 
@@ -102,6 +69,9 @@ build/Client tests/secure_user/client.conf get-endpoints opc.tcp://localhost:148
 
 # 5. Read the current time from the registered server
 build/Client tests/secure_user/client.conf read-time opc.tcp://localhost:14841
+
+# 6. Download the server's certificate to a local file
+build/Client tests/secure_user/client.conf download-cert opc.tcp://localhost:14841 server.der
 ```
 
 All three programs accept an optional log level as the last argument
@@ -117,6 +87,7 @@ Integration tests exercise four combinations of security and authentication:
 | `secure_anonymous` | SignAndEncrypt / Aes256_Sha256_RsaPss | anonymous |
 | `secure_user` | SignAndEncrypt / Aes256_Sha256_RsaPss | user/password |
 | `secure_cert` | SignAndEncrypt / Aes256_Sha256_RsaPss | X509 certificate |
+| `download_cert` | SignAndEncrypt / Aes256_Sha256_RsaPss | anonymous (download-cert) |
 
 Run all tests: