tw.writeString("ssh-dss");
tw.writeString(pk_enc, 0, pk_enc.length);
byte[] msg = tw.getBytes();
DSASignature ds = DSASHA1Verify.generateSignature(msg, pk, rnd);
byte[] ds_enc = DSASHA1Verify.encodeSSHDSASignature(ds);
PacketUserauthRequestPublicKey ua = new PacketUserauthRequestPublicKey("ssh-connection", user,
"ssh-dss", pk_enc, ds_enc);