Fix FIPS compatibility by using default KeyManagerFactory algorithm

Use KeyManagerFactory.getDefaultAlgorithm() instead of hardcoded
"SunX509" to support FIPS-compliant security providers like Bouncy
Castle that do not support the SunX509 algorithm.

Author: kuntzed

token-client/src/main/java/com/sap/cloud/security/mtls/SSLContextFactory.java

@@ -93,7 +93,7 @@ public SSLContext create(String x509Certificates, String privateKey)
 	 */
 	public SSLContext create(ClientIdentity clientIdentity) throws GeneralSecurityException, IOException {
 		KeyStore keystore = createKeyStore(clientIdentity);
-		KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance("SunX509");
+		KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
 		keyManagerFactory.init(keystore, noPassword);
 		SSLContext sslContext = createDefaultSSLContext();
 		sslContext.init(keyManagerFactory.getKeyManagers(), null, null);