feat: example-node Readme.md update (#92)

Adding example-node Readme.md
Cleaning up duplicate licensing language

Author: caitlin-tibbetts

modules/example-node/Readme.md

@@ -1,32 +1,40 @@
 # AWS Encryption SDK for Javascript Node.js examples
 
-This repository holds examples for encrypt and decrypt in Node.js.
-These examples are intended to work so you can experiment with functional code.
+This repository includes examples for encrypting and decrypting in Node.js. These are not for production use.
 
-# NOTE
-The CMK's in these examples *are only* for example.  They *are public*.
-Replace these CMK's with your own.
+To run this example, you must have an AWS account with at least one AWS Key Management Service (AWS KMS) customer managed CMK.
+To encrypt, the CMK must have kms:GenerateDataKey permission. 
+To decrypt, the CMK must have kms:Decrypt permission.
+The CMKs in these examples are only for *example*. *Replace these CMKs with your own*.
 
 ## KMS Simple
 
-This is the simples example.
-It encrypts and decrypts a simple string with KMS.
+This is an example of using the AWS Encryption SDK to encrypt and decrypt a simple string. 
+For a more detailed explanation, see kms_simple.ts.
 
 ## KMS Stream
 
-An example of encrypting a file stream with KMS.
+This is an example of using a KMS keyring to encrypt and decrypt a file stream. 
+For a more detailed explanation, see kms_stream.ts.
 
 ## KMS Regional Discovery
 
-KMS Keyrings can be put in `discovery` mode.
-This means that it will attempt to connect to any region.
-This is not always what you want.
-Perhapses for performance you want to limit attempts to a set of "close" regions.
-Perhapses for policy reason you want to exclude some regions.
+This is an example of using a KMS Regional Discovery Keyring that limits the AWS Encryption SDK to CMKs in a particular AWS Region(s).
+This is different from a KMS Discovery Keyring that doesn't specify any CMKs and will therefore use CMKs from any region available. 
+For a more detailed explanation, see kms_regional_discovery.ts.
 
 ## RSA Simple
 
-Sometimes you may want to use an RSA key to exchange secrets.
-This has some advantages, but comes with a heaved key management cost.
-If you can use KMS, the context guaranties are generally worth it.
-However, I still want to provide an example incase this fits your use case.
+This is an example of using a RSA key pair to encrypt and decrypt a simple string. 
+This has some advantages for certain use cases, but we recommend that you use a keyring that protects your wrapping keys and performs cryptographic operations within a secure boundary. A KMS keyring uses AWS Key Management Service (AWS KMS) customer master keys (CMKs) that never leave AWS KMS unencrypted. 
+For a more detailed explanation, see rsa_simple.ts.
+
+## How to Use
+
+To see these examples in action, run `npm test`.
+
+## License
+
+This SDK is distributed under the
+[Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0),
+see LICENSE.txt and NOTICE.txt for more information.

modules/example-node/src/kms_regional_discovery.ts

@@ -13,21 +13,6 @@
  * limitations under the License.
  */
 
-/*
- * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License"). You may not use
- * this file except in compliance with the License. A copy of the License is
- * located at
- *
- *     http://aws.amazon.com/apache2.0/
- *
- * or in the "license" file accompanying this file. This file 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.
- */
-
 import { KmsKeyringNode, limitRegions, excludeRegions, getKmsClient, decrypt } from '@aws-crypto/client-node'
 
 export async function kmsRegionalDiscoveryLimitTest (ciphertext: string|Buffer) {

modules/example-node/src/kms_simple.ts

@@ -13,21 +13,6 @@
  * limitations under the License.
  */
 
-/*
- * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License"). You may not use
- * this file except in compliance with the License. A copy of the License is
- * located at
- *
- *     http://aws.amazon.com/apache2.0/
- *
- * or in the "license" file accompanying this file. This file 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.
- */
-
 import { KmsKeyringNode, encrypt, decrypt } from '@aws-crypto/client-node'
 
 export async function kmsSimpleTest () {

modules/example-node/src/rsa_simple.ts

@@ -13,21 +13,6 @@
  * limitations under the License.
  */
 
-/*
- * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License"). You may not use
- * this file except in compliance with the License. A copy of the License is
- * located at
- *
- *     http://aws.amazon.com/apache2.0/
- *
- * or in the "license" file accompanying this file. This file 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.
- */
-
 import { RawRsaKeyringNode, encrypt, decrypt } from '@aws-crypto/client-node'
 
 import { generateKeyPair } from 'crypto'