C# examples for all new canonical examples

[mattsb42-aws]

We are standardizing examples across all implementations. We started with Python[1] and Java[2], so all new implementations need to match those examples.

Related to awslabs/aws-encryption-sdk-specification#103, it is important that these examples be as near as possible direct copies. The premise wording needs to be the same, wording of the step-by-step comments need to be the same, and we need to hit all the major points in the example.

Necessary Examples

API

• How to encrypt and decrypt
• How to change the algorithm suite
• How to encrypt and decrypt data streams in memory
• How to encrypt and decrypt data streamed between files

Keyrings

AWS KMS

• How to use one AWS KMS CMK
• How to use multiple AWS KMS CMKs in different regions
• How to decrypt when you don't know the CMK
• How to decrypt within a region
• How to decrypt with a preferred region but failover to others
• How to use AWS KMS clients with custom configuration (details pending client supplier discussions)
• How to use different AWS KMS client for different regions (details pending client supplier discussions)

Raw keyrings

• How to use a raw AES wrapping key
  • doc(example): examples dir, and RawAESKeyring example #281
• How to use a raw RSA wrapping key
  • doc(example): RawRSAKeyring examples #313
• How to use a raw RSA wrapping key when the key is PEM or DER encoded
  • doc(example): RawRSAKeyring examples #313
• How to encrypt with a raw RSA public key wrapping key without access to the private key
  • doc(example): RawRSAKeyring examples #313

Multi-keyrings

• How to combine AWS KMS with an offline escrow key

Cryptographic Materials Managers

• How to reuse data keys across multiple messages
• How to restrict algorithm suites
• How to require encryption context fields

[1] https://github.com/aws/aws-encryption-sdk-python/tree/master/examples
[2] https://github.com/aws/aws-encryption-sdk-java/tree/master/src/examples