diff --git a/src/main/java/net/schmizz/sshj/common/SecurityUtils.java b/src/main/java/net/schmizz/sshj/common/SecurityUtils.java
index 8406c3a6..5d6ac05b 100644
--- a/src/main/java/net/schmizz/sshj/common/SecurityUtils.java
+++ b/src/main/java/net/schmizz/sshj/common/SecurityUtils.java
@@ -249,7 +249,14 @@ public static synchronized Signature getSignature(String algorithm)
      */
     public static synchronized boolean isBouncyCastleRegistered() {
         register();
-        return BOUNCY_CASTLE.equals(securityProvider) || SPONGY_CASTLE.equals(securityProvider);
+        Provider[] providers = Security.getProviders();
+        for (Provider provider : providers) {
+            String name = provider.getName();
+            if (BOUNCY_CASTLE.equals(name) || SPONGY_CASTLE.equals(name)) {
+                return true;
+            }
+        }
+        return false;
     }
 
     public static synchronized void setRegisterBouncyCastle(boolean registerBouncyCastle) {
diff --git a/src/main/java/net/schmizz/sshj/transport/kex/ECDHNistP.java b/src/main/java/net/schmizz/sshj/transport/kex/ECDHNistP.java
index 53aa52e2..be836680 100644
--- a/src/main/java/net/schmizz/sshj/transport/kex/ECDHNistP.java
+++ b/src/main/java/net/schmizz/sshj/transport/kex/ECDHNistP.java
@@ -19,9 +19,9 @@
 import net.schmizz.sshj.transport.digest.SHA256;
 import net.schmizz.sshj.transport.digest.SHA384;
 import net.schmizz.sshj.transport.digest.SHA512;
-import org.bouncycastle.jce.spec.ECNamedCurveGenParameterSpec;
 
 import java.security.GeneralSecurityException;
+import java.security.spec.ECGenParameterSpec;
 
 public class ECDHNistP extends AbstractDHG {
 
@@ -33,7 +33,7 @@ public static class Factory521
 
         @Override
         public KeyExchange create() {
-            return new ECDHNistP("P-521", new SHA512());
+            return new ECDHNistP("secp521r1", new SHA512());
         }
 
         @Override
@@ -48,7 +48,7 @@ public static class Factory384
 
         @Override
         public KeyExchange create() {
-            return new ECDHNistP("P-384", new SHA384());
+            return new ECDHNistP("secp384r1", new SHA384());
         }
 
         @Override
@@ -63,7 +63,7 @@ public static class Factory256
 
         @Override
         public KeyExchange create() {
-            return new ECDHNistP("P-256", new SHA256());
+            return new ECDHNistP("secp256r1", new SHA256());
         }
 
         @Override
@@ -79,7 +79,7 @@ public ECDHNistP(String curve, Digest digest) {
 
     @Override
     protected void initDH(DHBase dh) throws GeneralSecurityException {
-        dh.init(new ECNamedCurveGenParameterSpec(curve), trans.getConfig().getRandomFactory());
+        dh.init(new ECGenParameterSpec(curve), trans.getConfig().getRandomFactory());
     }
 
 }