Suzuri is a secure and easy to use token format that employs
XChaCha20-Poly1305 AEAD symmetric encryption to create
authenticated, encrypted, tamperproof tokens.

It compresses and encrypts an arbitrary sequence of bytes,
then encodes the result to url-safe Base64.

Suzuri tokens can be used as a secure alternative to JWT
or for any type of general purpose message passing.

1. Add the dependency to your shard.yml:

   dependencies:
     suzuri:
       github: busyloop/suzuri

2. Run shards install

• API Documentation

require "suzuri"

TEST_KEY = "TheKeyLengthMustBeThirtyTwoBytes"

## Encode
token_str = Suzuri.encode("hello world", TEST_KEY) # => "(url-safe base64)"

## Decode
token = Suzuri.decode(token_str, TEST_KEY)   # => Suzuri::Token
token.to_s                                   # => "hello world"
token.timestamp                              # => 2020-01-01 01:23:45.0 UTC

## Decode with a TTL constraint
token_str = Suzuri.encode("hello world", TEST_KEY) # => "(url-safe base64)"
sleep 5
Suzuri.decode(token_str, TEST_KEY, 2.seconds) # => Suzuri::Error::TokenExpired

require "suzuri/json_serializable"

TEST_KEY = "TheKeyLengthMustBeThirtyTwoBytes"

class Person
   include JSON::Serializable

   @[JSON::Field]
   property name : String

   def initialize(@name)
   end
end

bob = Person.new(name: "bob")
token_str = bob.to_suzuri(TEST_KEY)

bob2 = Person.from_suzuri(token_str, TEST_KEY)
bob2.name # => "bob"

By default Suzuri applies zstd compression before encryption when the
payload is larger than 512 bytes. The compression threshold and level
can be chosen at runtime.

1. Fork it (https://github.com/busyloop/suzuri/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Suzuri is inspired by (but not compatible to) Branca-tokens. The underlying encryption is identical.
Suzuri adds compression support and serializes to url-safe Base64 instead of Base62.