Implemented image encryption/decryption libraries and ctr commands

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Brandon Lum <lumjjb@gmail.com>

cmd/ctr/commands/utils.go

@@ -0,0 +1,27 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package commands
+
+// IntToInt32Array converts an array of int's to int32's
+func IntToInt32Array(in []int) []int32 {
+	var ret []int32
+
+	for _, v := range in {
+		ret = append(ret, int32(v))
+	}
+	return ret
+}