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a light-weight cryptographically signed key value store inspired by IPNS
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storage.go updated server to work with aws Aug 26, 2018

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hashmap server is a light-weight cryptographically signed public key value store inspired by JWT and IPNS.

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The goal of hashmap is to serve as a key-value store for cryptographically signed payloads namespaced by the hash of the public key used to verify the signature. This allows for:

  • a unique pubkey hash name spacing (one ed25519 key pair per key-value entry)
  • only the private key holder can update its corresponding public key hash endpoint
  • the validity of the endpoint and the response authenticity are verifiable by all parties

The design goals were to allow a submitter to randomly generate ed25519 keys to use for submission. Hashmap doesn't keep any user data or auth systems other than ensuring that a submitted key-value pair are cryptographically authentic and properly formatted.

A tool like hashmap is useful as a light-weight and mobile device friendly mutable storage endpoint. This tool is heavily inspired by IPNS, the mutable store used by the IPFS project to point to specific IPFS hashes.

One benefit of hashmap being decoupled from IPFS specifically is that its message store supports client-side encryption and therefore, a submitter who obfuscates the source IP through an anomemity network like TOR and encrypts its message client-side can can publicly store mutable data without the hashmap server having knowledge or origin of the submission nor contents of the message.


  • endpoints are hashed using the multi-hash format and default to blake2b-256 hashes
  • signed data uses nacl sign which leverages ed25519
  • signed payload submission and acceptance are strictly enforced based on signature validity, message size, and date-stamp accuracy
  • values stored in hashmap have a max time-to-live of 1 week and default to 24 hours.

The structure of a properly formatted payload submission is a follows:

  "data":   "BASE_64_ENCODED_STRING",
  "sig":    "BASE_64_ENCODED_STRING",
  "pubkey": "BASE_64_ENCODED_STRING"

The integrity of the contents of data are verifiable with the sig and the pubkey. But to know which signature method to use will require decoding the contents of data.

The contents of data decoded is:

  "message":   "BASE_64_ENCODED_STRING",
  "timestamp": 1535211171864296000,
  "ttl":       86400,
  "sigMethod": "nacl-sign-ed25519",
  "version":   "0.0.1"
  • message is a BASE_64_ENCODED_STRING provided by the submitter. This may contain anything as long as the message bytes is less than 512 bytes.
  • timestamp is unix-time in nanoseconds. Hashmap Server allows MaxSubmitDrift of 15 seconds. This prevents old payloads from overwriting newer payloads.
  • ttl - is the time to live in seconds for the payload. If no TTL is set (or it is set to 0) hashmap defaults to 24 hours (86400 seconds ). A Maximum TTL of 1 week (604800 seconds) is permitted. Any TTL greater than 604800 will be rejected.
  • sigMethod outlines the method used to verify the signature. Currently only nacl-sign-ed25519 is supported
  • version is used for handling potentially breaking changes in the future, but it isn't currently analyzed for acceptance.

For a hashmap payload to be accepted:

  • Signature must be valid
  • Timestamp must be within the time drift threshold
  • TTL must be valid
  • Message size must be valid

If a payload is accepted, the server will respond with something similar to:

  "endpoint": "2Drjgb7y6LmSaGZhw5pJrhpB4MrgVcajMXwnb8yWUavavaBSHo"

This endpoint is the blake2b-256 multi-hash of the submitted public key in the payload. This is the endpoint that can be used to retrieve the submitted payload.

Hashmap responds in the exact payload as that which was submitted:

  "data":   "BASE_64_ENCODED_STRING",
  "sig":    "BASE_64_ENCODED_STRING",
  "pubkey": "BASE_64_ENCODED_STRING"

This means that any requestor can independently verify that:

  • the payload data is valid based on the signature
  • the TTL has not expired
  • the pubkey multihash matches the pubkey contained in the payload


This is a very early and incomplete prototype of the hashmap server and basic tools. Currently the backing store defaults to a simple in-memory store but redis is also supported. This code needs test coverage and possibly some rethinking on some of the structures, but this is working as an MVP.

Basic instructions

While in development, the easiest way to run the hashmap CLI tool is to run


you can run the hashmap server locally without TLS certificate files from the cli with:

hashmap run --TLS=false

The server runs on localhost:3000

You can test sending a properly formatted json payload by using curl (read below to find out how to use hashmap generate to generate a key and a payload)

curl -X POST http://localhost:3000 -d @payload.json

This will respond with a multihash base58 encoded pubkey hash

You can use this hash to query hashmap like this:

curl http://localhost:3000/2DrjgbD2fh4CL6HX5qYqKf7ULr3hwJXQgYn9sTCQSLpHAqj5n2

Other instructions

Also included in hashmap command are tools to make it easier to generate and ed25519 private key as well as generate a properly formatted payload for submitting to the hashmap server.

Generating an ed25519 private key

You can generate a key to stdout encoded to base64 with:

hashmap generate key

Saving the private key

If you'd like to save that key to a file for future use, its as easy as:

hashmap generate key > priv.key

Generating a Payload

If you'd like to generate a payload with defaults use:

hashmap generate payload < priv.key

you can also change the default payload data for data, timestamp, and ttl. To look at the CLI options you can use the help flag

hashmap generate payload --help

an example of modifying the inputs is as follows:

hashmap generate payload --message="{\"hello\":\"world\"}" --timestamp=1535211171864296000 --ttl=5 < priv.key

you can save this ouput to a file as follows:

hashmap generate payload < priv.key > payload.json

Analyzing a Payload

To analyze a payload, you can run the analyzer as follows:

hashmap analyze < payload.json


  "sig": "s5tHkDsMfUQbsJGJf80lKdkI4kTEf9BJ3a1PCqSnYuH0aZ8kjeVG2SoGeeRsaXMNV4nDYlBddJkeQkGWort3Cg==",
  "pubkey": "9DHEtybGV0LxFFV3WBFMZzrvyme/3o1pP9Q6SD5t3NA="


  "message": "eyJjcnlwdG8iOnsibWV0aG9kIjoic2VjcmV0Ym94IiwiY2h1bmsiOjE2MDAwfSwiaGFzaCI6ImUxZjE1MzRkMjZkMiIsInBheWxvYWQiOiJ1bzhaUWVNVWxpOGIrSW9KQ1JiL25Pd01XUGdpOGVDZEVCTXdkamp6R2Y3UU1jZGg2TWVQUmorWnB3UFdzNVhqdWNpMmEzRTU3Q1VPdHR3SEFHdz0ifQ==",
  "timestamp": 1535211171864296000,
  "ttl": 300,
  "sigMethod": "nacl-sign-ed25519",
  "version": "0.0.1"




Verify Payload         : PASS
Validate TTL           : PASS
Validate Timestamp     : PASS
Validate Message Size  : PASS
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