| // Copyright 2020 The Monogon Project Authors. | 
 | // | 
 | // SPDX-License-Identifier: Apache-2.0 | 
 | // | 
 | // 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 pki implements an x509 PKI (Public Key Infrastructure) system backed | 
 | // on etcd. | 
 | // | 
 | // The PKI is made of Certificates, all constrained within a Namespace. The | 
 | // Namespace allows for multiple users of this library to co-exist on a single | 
 | // etcd server. | 
 | // | 
 | // Any time a Certificate object is created, it describes the promise (or | 
 | // intent) of an x509 certificate to exist. For every created Certifiacte an | 
 | // Issuer must be specified - either another Certificate (which will act as a | 
 | // CA and sign that Certificate), or SelfSigned (which will cause the | 
 | // Certificate to be self-signed when generated). | 
 | // | 
 | // Once a Certificate object is created, a call to Ensure() must be placed to | 
 | // turn the intent of a certificate into physical bytes that can then be | 
 | // accessed by the appliaction. | 
 | // | 
 | // Two kinds of Certificates can be created: | 
 | //  - Named certificates are stored in etcd, and an Ensure call will either | 
 | //    create them, or return a Certificate already stored in etcd. Multiple | 
 | //    concurrent calls to Ensure for a Certificate with the same name are | 
 | //    permitted, even across machines, as long as the Certificate intent data | 
 | //    is the same. If not, it is still safe to perform this action | 
 | //    concurrently, but the first transaction will win, causing the losing | 
 | //    transaction to return the Ensure call with a certificate that was not | 
 | //    based on the same intent. | 
 | //    It is the responsibility of the caller to ensure these cases are handled | 
 | //    gracefully. | 
 | //  - Volatile certificates are stored in memory, and have an empty ("") name. | 
 | //    Any time Ensure is called, the certificate already present in memory is | 
 | //    returned, or one is created if it does not yet exist. | 
 | //    Currently, these certificates live fully in memory, but in the future we | 
 | //    will likely perform audit logging (and revocation) of these certificate | 
 | //    within etcd, too. | 
 | // | 
 | package pki |