Ensure reset of security provider preference. (#1013)

README.adoc

@@ -110,6 +110,18 @@ Issue tracker: https://github.com/hierynomus/sshj/issues
 Fork away!
 
 == Release history
+SSHJ 0.39.0 (2024-02-20)::
+* Upgraded dependencies
+* Remove hard dependencies on BouncyCastle, making it optional.
+* Merged https://github.com/hierynomus/sshj/pull/993[#993]: Remove EDDSA dependency
+* Merged https://github.com/hierynomus/sshj/pull/959[#959]: Improve Curve25519 public key handling
+* Merged https://github.com/hierynomus/sshj/pull/911[#911]: Fix for bad packet received with heartbeat enabled
+* Merged https://github.com/hierynomus/sshj/pull/926[#926]: Close session when closing SFTP client
+* Merged https://github.com/hierynomus/sshj/pull/928[#928]: Improve file-listing performance
+* Merged https://github.com/hierynomus/sshj/pull/934[#934]: Don't send keep-alive before KEX done
+* Merged https://github.com/hierynomus/sshj/pull/936[#936]: Improve Base64 decoding error handling
+* Merged https://github.com/hierynomus/sshj/pull/925[#925]: Allow passing connected sockets
+* Merged https://github.com/hierynomus/sshj/pull/922[#922]: Fix bug in known_hosts parsing
 SSHJ 0.38.0 (2024-01-02)::
 * Mitigated CVE-2023-48795 - Terrapin
   * Merged https://github.com/hierynomus/sshj/pull/917[#917]: Implement OpenSSH strict key exchange extension

src/main/java/net/schmizz/sshj/common/SecurityUtils.java

@@ -276,6 +276,9 @@ public class SecurityUtils {
      */
     public static synchronized void setSecurityProvider(String securityProvider) {
         SecurityUtils.securityProvider = securityProvider;
+        if(null == securityProvider) {
+            SecurityUtils.registerBouncyCastle = null;
+        }
         registrationDone = false;
     }
 

src/test/java/net/schmizz/sshj/transport/kex/Curve25519DHTest.java

@@ -17,6 +17,7 @@ package net.schmizz.sshj.transport.kex;
 
 import net.schmizz.sshj.common.SecurityUtils;
 import net.schmizz.sshj.transport.random.JCERandom;
+import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
@@ -43,6 +44,7 @@ public class Curve25519DHTest {
     };
 
     @BeforeEach
+    @AfterEach
     public void clearSecurityProvider() {
         SecurityUtils.setSecurityProvider(null);
     }