42 lines
1.6 KiB
Go
42 lines
1.6 KiB
Go
// Package digest provides a generalized type to opaquely represent message
|
|
// digests and their operations within the registry. The Digest type is
|
|
// designed to serve as a flexible identifier in a content-addressable system.
|
|
// More importantly, it provides tools and wrappers to work with
|
|
// hash.Hash-based digests with little effort.
|
|
//
|
|
// Basics
|
|
//
|
|
// The format of a digest is simply a string with two parts, dubbed the
|
|
// "algorithm" and the "digest", separated by a colon:
|
|
//
|
|
// <algorithm>:<digest>
|
|
//
|
|
// An example of a sha256 digest representation follows:
|
|
//
|
|
// sha256:7173b809ca12ec5dee4506cd86be934c4596dd234ee82c0662eac04a8c2c71dc
|
|
//
|
|
// In this case, the string "sha256" is the algorithm and the hex bytes are
|
|
// the "digest".
|
|
//
|
|
// Because the Digest type is simply a string, once a valid Digest is
|
|
// obtained, comparisons are cheap, quick and simple to express with the
|
|
// standard equality operator.
|
|
//
|
|
// Verification
|
|
//
|
|
// The main benefit of using the Digest type is simple verification against a
|
|
// given digest. The Verifier interface, modeled after the stdlib hash.Hash
|
|
// interface, provides a common write sink for digest verification. After
|
|
// writing is complete, calling the Verifier.Verified method will indicate
|
|
// whether or not the stream of bytes matches the target digest.
|
|
//
|
|
// Missing Features
|
|
//
|
|
// In addition to the above, we intend to add the following features to this
|
|
// package:
|
|
//
|
|
// 1. A Digester type that supports write sink digest calculation.
|
|
//
|
|
// 2. Suspend and resume of ongoing digest calculations to support efficient digest verification in the registry.
|
|
//
|
|
package digest
|