Implement gateway S3 support (#3940)

vendor/github.com/minio/minio-go/pkg/encrypt/interface.go

@@ -0,0 +1,50 @@
+/*
+ * Minio Go Library for Amazon S3 Compatible Cloud Storage (C) 2017 Minio, Inc.
+ *
+ * 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 encrypt implements a generic interface to encrypt any stream of data.
+// currently this package implements two types of encryption
+// - Symmetric encryption using AES.
+// - Asymmetric encrytion using RSA.
+package encrypt
+
+import "io"
+
+// Materials - provides generic interface to encrypt any stream of data.
+type Materials interface {
+
+	// Returns encrypted/decrypted data, io.Reader compatible.
+	Read(b []byte) (int, error)
+
+	// Get randomly generated IV, base64 encoded.
+	GetIV() (iv string)
+
+	// Get content encrypting key (cek) in encrypted form, base64 encoded.
+	GetKey() (key string)
+
+	// Get user provided encryption material description in
+	// JSON (UTF8) format. This is not used, kept for future.
+	GetDesc() (desc string)
+
+	// Setup encrypt mode, further calls of Read() function
+	// will return the encrypted form of data streamed
+	// by the passed reader
+	SetupEncryptMode(stream io.Reader) error
+
+	// Setup decrypted mode, further calls of Read() function
+	// will return the decrypted form of data streamed
+	// by the passed reader
+	SetupDecryptMode(stream io.Reader, iv string, key string) error
+}