Revert "Revert "SSHD: Allow ECDSA based public key authentication""

This reverts commit ef74c883e6cc07c0a55f14960dfc31b0feafc39e.

Change-Id: I365c57365b4ea7271f104b8040f951b088cf80ab

gerrit-sshd/src/main/java/com/google/gerrit/sshd/SshDaemon.java

diff --git a/gerrit-sshd/src/main/java/com/google/gerrit/sshd/SshDaemon.java b/gerrit-sshd/src/main/java/com/google/gerrit/sshd/SshDaemon.java
index 7f3612b..595b5d2 100644
--- a/gerrit-sshd/src/main/java/com/google/gerrit/sshd/SshDaemon.java
+++ b/gerrit-sshd/src/main/java/com/google/gerrit/sshd/SshDaemon.java
@@ -83,6 +83,7 @@
 import org.apache.sshd.common.session.AbstractSession;
 import org.apache.sshd.common.session.ConnectionService;
 import org.apache.sshd.common.signature.SignatureDSA;
+import org.apache.sshd.common.signature.SignatureECDSA;
 import org.apache.sshd.common.signature.SignatureRSA;
 import org.apache.sshd.common.util.Buffer;
 import org.apache.sshd.common.util.SecurityUtils;
@@ -510,7 +511,11 @@
 
   private void initSignatures() {
     setSignatureFactories(Arrays.<NamedFactory<Signature>> asList(
-        new SignatureDSA.Factory(), new SignatureRSA.Factory()));
+        new SignatureDSA.Factory(),
+        new SignatureRSA.Factory(),
+        new SignatureECDSA.NISTP256Factory(),
+        new SignatureECDSA.NISTP384Factory(),
+        new SignatureECDSA.NISTP521Factory()));
   }
 
   private void initCompression() {