Drop generic ALTS page (#540)

Contributes to #527

content/docs/guides/auth/ALTS.md

@@ -1,69 +0,0 @@
----
-title: ALTS authentication
-description: >
-  An overview of gRPC authentication using Application Layer Transport Security
-  (ALTS).
----
-
-### Overview
-
-Application Layer Transport Security (ALTS) is a mutual authentication and
-transport encryption system developed by Google. It is used for securing RPC
-communications within Google's infrastructure. ALTS is similar to mutual TLS
-but has been designed and optimized to meet the needs of Google's production
-environments. For more information, take a look at the
-[ALTS whitepaper](https://cloud.google.com/security/encryption-in-transit/application-layer-transport-security).
-
-ALTS in gRPC has the following features:
-
-- Create gRPC servers & clients with ALTS as the transport security protocol.
-- ALTS connections are end-to-end protected with privacy and integrity.
-- Applications can access peer information such as the peer service account.
-- Client authorization and server authorization support.
-- Minimal code changes to enable ALTS.
-
-gRPC users can configure their applications to use ALTS as a transport security
-protocol with few lines of code. gRPC ALTS is supported in C++, Java, Go, and
-Python.
-
-Details are covered in this page, or in the following language-specific
-pages:
-
-- [ALTS in C++]({{< relref "docs/languages/cpp/alts" >}})
-- [ALTS in Go]({{< relref "docs/languages/go/alts" >}})
-- [ALTS in Java]({{< relref "docs/languages/java/alts" >}})
-- [ALTS in Python]({{< relref "docs/languages/python/alts" >}})
-
-Note that ALTS is fully functional if the application runs on
-[Google Cloud Platform](https://cloud.google.com). ALTS could be run on any
-platforms with a pluggable
-[ALTS handshaker service](https://github.com/grpc/grpc/blob/7e367da22a137e2e7caeae8342c239a91434ba50/src/proto/grpc/gcp/handshaker.proto#L224-L234).
-
-### gRPC Client with ALTS Transport Security Protocol
-
-gRPC clients can use ALTS credentials to connect to servers. The following
-provides examples of how to set up such clients in all supported gRPC languages.
-
-### gRPC Server with ALTS Transport Security Protocol
-
-gRPC servers can use ALTS credentials to allow clients to connect to them. The
-following provides examples of how to set up such servers in all supported gRPC
-languages.
-
-### Server Authorization
-
-gRPC has built-in server authorization support using ALTS. A gRPC client using
-ALTS can set the expected server service accounts prior to establishing a
-connection. Then, at the end of the handshake, server authorization guarantees
-that the server identity matches one of the service accounts specified
-by the client. Otherwise, the connection fails.
-
-### Client Authorization
-
-On a successful connection, the peer information (e.g., client’s service
-account) is stored in the
-[AltsContext](https://github.com/grpc/grpc/blob/master/src/proto/grpc/gcp/altscontext.proto).
-gRPC provides a utility library for
-client authorization check. Assuming that the server knows the expected client
-identity (e.g., foo@iam.gserviceaccount.com), it can run the following example
-codes to authorize the incoming RPC.

layouts/index.redirects

@@ -1,5 +1,8 @@
 # cSpell:ignore channelz helloasync loadbalancing quickstart sapi vendasta vendastagrpc
 
+# ALTS page is now language-specific (#527); redirect to base auth page for now
+/docs/guides/auth/alts  /docs/guides/auth
+
 # Languages -> platforms redirects
 
 /docs/languages/android/*  /docs/platforms/android/java/:splat