diff --git a/kdc/fast.c b/kdc/fast.c
new file mode 100644
index 000000000..719bac212
--- /dev/null
+++ b/kdc/fast.c
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 1997-2007 Kungliga Tekniska Högskolan
+ * (Royal Institute of Technology, Stockholm, Sweden).
+ * All rights reserved.
+ *
+ * Portions Copyright (c) 2010 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "kdc_locl.h"
+
+krb5_error_code
+_kdc_fast_mk_response(krb5_context context,
+		      krb5_crypto armor_crypto,
+		      METHOD_DATA *pa_data,
+		      krb5_keyblock *strengthen_key,
+		      KrbFastFinished *finished,
+		      krb5uint32 nonce,
+		      krb5_data *data)
+{
+    PA_FX_FAST_REPLY fxfastrep;
+    KrbFastResponse fastrep;
+    krb5_error_code ret;
+    krb5_data buf;
+    size_t size;
+
+    memset(&fxfastrep, 0, sizeof(fxfastrep));
+    krb5_data_zero(data);
+
+    fastrep.padata.val = pa_data->val;
+    fastrep.padata.len = pa_data->len;
+    fastrep.strengthen_key = strengthen_key;
+    fastrep.finished = finished;
+    fastrep.nonce = nonce;
+
+    ASN1_MALLOC_ENCODE(KrbFastResponse, buf.data, buf.length,
+		       &fastrep, &size, ret);
+    if (ret)
+	return ret;
+    if (buf.length != size)
+	krb5_abortx(context, "internal asn.1 error");
+    
+    fxfastrep.element = choice_PA_FX_FAST_REPLY_armored_data;
+
+    ret = krb5_encrypt_EncryptedData(context,
+				     armor_crypto,
+				     KRB5_KU_FAST_REP,
+				     buf.data,
+				     buf.length,
+				     0,
+				     &fxfastrep.u.armored_data.enc_fast_rep);
+    krb5_data_free(&buf);
+    if (ret)
+	return ret;
+
+    ASN1_MALLOC_ENCODE(PA_FX_FAST_REPLY, data->data, data->length,
+		       &fxfastrep, &size, ret);
+    free_PA_FX_FAST_REPLY(&fxfastrep);
+    if (ret)
+	return ret;
+    if (data->length != size)
+	krb5_abortx(context, "internal asn.1 error");
+    
+    return 0;
+}