Quick Start


Cryptowerk Horizon API writes hashes of data into the Bitcoin and Ethereum blockchain by default. Hashes will be submitted in the /register call and the result contains a unique retrieval-ID. Cryptowerk bundles the collected hashes and creates a single super-hash. This super-hash is then anchored into the blockchains of your choice. After the super-hash has been anchored in one or more blockchains, the retrieval-ID may be exchanged for a Seal. A Seal contains the information necessary to prove that a hash was written to a blockchain.

The flows supported by this API are:

Hash --> retrieval-ID --> Seal

What you will need

  • Cryptowerk Horizon API credentials
  • Terminal or Command Prompt access

Getting Started

API Key and Credentials

Sign-up or Login via the Cryptowerk website

Select the Account menu and locate the API Key and Secret Credential. Save these two values with a space in between them. You can only view the credentials once.

get api key image

The API Key is visible and can always be looked up in your Account info in the App Console. Your API Credential is secret and may only be accessed once.

Hash The data

A cryptographic hash is like a fingerprint. It is a mathematical algorithm that takes data of any size turns it into a unique fixed size string of values. Cryptowerk uses these so called hashes to create Seals for digital assets. Open a command line terminal

echo -n "simple text" | shasum -a 256

Create a Hash:


You most likely want to hash a document. To hash a document/file try this:

openssl dgst -sha256 <filename>

Call Register API with Hashes

Using the values from step 1 and 2 open a terminal and enter

curl -sS \
--header "X-ApiKey: +jR2fbECXo7rDIRrPL9otvIkn54G7+kF9b1LvNe/kOg= wZ2vV5kYfDGEFsyXVZwSHBjN1TfzQovZE340hnsCRWk=" \
--data "hashes=2609c7c28788898a337c063ff1c3b92275832bddeda014a790d109fad3ba85e2" \

The retrieval-ID for each hash can be found in the response JSON of a successful /register call.


There are several approaches to retrieve the Seal but here we will focus on the simplest.

Polling for Seal

Call /verify and provide the retrieval-ID(s) then check for the return value.

curl -sS \
--header "X-ApiKey: +jR2fbECXo7rDIRrPL9otvIkn54G7+kF9b1LvNe/kOg= wZ2vV5kYfDGEFsyXVZwSHBjN1TfzQovZE340hnsCRWk=" \
--data "retrievalId=ri323399645982466fe76eb43010c7f5572c4182e711bfae9f8db9b2407f85a648c" \

For each retrieval-ID (i.e. each hash) a Seal is returned in the response JSON of a successful /verify call. A Seal contains Proofs. A Proof is a set of instructions for calculating and locating the anchor-hash that was written as a transaction in a block of a blockchain. There is a Proof for each blockchain that gets written to. A Seal may contain one or more Proofs depending on the number of blockchains you are writing to and the exact timing of each confirmation.

"maxSupportedAPIVersion": 8,
"documents": [{
"retrievalId": "ri323399645982466fe76eb43010c7f5572c4182e711bfae9f8db9b2407f85a648c",
"seal": {
"documentInfo": {
"submittedAt": 1570585798468
"proofs": [{
"bundleMethod": "BALANCED_MERKLE_TREE",
"operations": [{
"blockChainId": "0x7f435eb59c1ece1d938cf9572c485a6e7208267b972c4a504945485951041443",
"instanceName": "4",
"insertedIntoBlockchainAt": 1570585861800,
"opcode": "BLOCKCHAIN",
"blockchainGeneralName": "Ethereum"
}, {
"docHash": "2609c7c28788898a337c063ff1c3b92275832bddeda014a790d109fad3ba85e2",
"opcode": "DOC_SHA256"
}, {
"opcode": "APPEND_THEN_SHA256",
"hash": "9c81d330a82cc58dafdab97093d841f5fa8f92d77eac54d0f1a23b22c2d187a3"
}, {
"opcode": "ANCHOR_SHA256",
"hash": "51fba877fcf44c28a44d81358e27425c06253964813b5277a183f894de5df22f"
"version": 8,
"isComplete": false
"submittedAt": 1570585798468,
"hasBeenInsertedIntoAtLeastOneBlockchain": true,
"blockchainRegistrations": [{
"blockChainId": "0x7f435eb59c1ece1d938cf9572c485a6e7208267b972c4a504945485951041443",
"insertedIntoBlockchainAt": 1570585861800,
"blockChainDesc": {
"instanceName": "4",
"generalName": "Ethereum"
"status": {
"anchorHash": "51fba877fcf44c28a44d81358e27425c06253964813b5277a183f894de5df22f"
"hasBeenInsertedIntoAllRequestedBlockchains": false
"minSupportedAPIVersion": 1

Above you will notice this Seal contains one Proof for the Ethereum blockchain. You may also notice that not all the requested blockchains have been written to yet. Blockchains often have different heartbeats at which they write and confirm transactions and blocks. Re-Polling the API /verify call will return the Seal with all the Proofs that have been confirmed at that time of the API call.