qed-docs

The QED REST API provides an easy way to leverage blockchain technology attaching immutable timestamps to your files.

For IOS we also provide an SDK wrapper around the API. IOS QEDSDK

Usage

Each HTTP request has to be authenticated by an API key. In order to use the QED REST API, you must obtain an API Key. Please get in contact: mail@qed.digital.

The API key is submitted via the Authorization header as app-token <API_KEY>, i.e.

curl -X POST \
    https://api.qed.digital/...
    -H 'Authorization: app-token l1MttwRc4SJcuQwDabcDFF23noLjgEyUFmWZZZIgCVekwlOmBmGtDtaEvxJHBuM3'

Storing a hash to the blockchain

An array of 32 bytes can be stored to the blockchain. In order to make the hash of your file collision-free we highly recommend to use SHA256 as the hashing algorithm to securely create a checksum for your file. The hash is expected to be encoded as a hex digest.

Endpoint

https://api.qed.digital/v1/reports/

Data

Key	Type	Description	Example
name	string	an arbitrary title	"My new appartement"
note	string	an arbitrary note	"This is so amazing."
hash	string	hex encoded string representing a byte array (maximum bytes 32)	"646412deadbeef8812"

cURL example

curl -X POST \
    https://api.qed.digital/v1/reports/ \
    -H 'Authorization: app-token l1MttwRc4SJcuQwDabcDFF23noLjgEyUFmWZZZIgCVekwlOmBmGtDtaEvxJHBuM3' \
    -H 'Content-Type: application/json' \
    -d '{
        "name": "My new appartement", // an arbitrary title as string,
        "note": "This is so amazing.", // an arbitrary note as string,
        "hash": "deadbeef" // hex encoded string representing a byte array (maximum bytes 32)
    }'

Output

Due to the asynchronous nature of the blockchain interaction, a report can have different states which are directly related to the transaction state on the blockchain. At which time a blockchain transaction is available and confirmed depends on both low level implementation details of the concrete chain and the high level SDKs wrapping blockchain interaction functionalities.

For a more detailed description of the transaction resource, please jump to the transaction section.

{
  "slug": "U1FKSif",
  "status": "pending", // "pending"|"confirmed"|"failed"
  "name": "My new appartement",
  "note": "This is so amazing",
  "hash": "deadbeef",
  "tx": {
     "hash": "af051c4d7a44a43459661b0943153d929f5370beacfeedc6cde6545fae981969" // deterministic hash of the transaction which can be used to access details of the transaction
     // More transaction details as soon as the transaction has been successfully processed by the blockchain network
  }
}

Retrieving the report status

Endpoint

https://api.qed.digital/v1/reports/<slug>

cURL example

curl -X GET \
    https://api.qed.digital/v1/reports/U1FKSif \
    -H 'Authorization: app-token l1MttwRc4SJcuQwDabcDFF23noLjgEyUFmWZZZIgCVekwlOmBmGtDtaEvxJHBuM3' \
    -H 'Content-Type: application/json'

Output

{
  "slug": "U1FKSif",
  "status": "confirmed",
  "name": "My new appartement",
  "note": "This is so amazing",
  "hash": "deadbeef",
  "tx": {
     "hash": "af051c4d7a44a43459661b0943153d929f5370beacfeedc6cde6545fae981969"
     "data": {...}, // generic JSON object (Blockchain implementation specific)
     "block_height": 8872466,
     "block_time": "2018-05-09T11:32:03Z",
     "explorer_url": "https://testnet.steexp.com/tx/642b0791738b1d202cb2e6d3c7fd811310cf0d990baba1a2b418cc4123a970b6",
     "network_name": "Stellar Testnet",
     "network_id": "cee0302d59844d32bdca915c8203dd44b33fbb7edc19051ea37abedf28ecd472"
  }
}

Transaction information

Key	Type	Description	Example
hash	string	Deterministic hash of the transaction which can be used to access details of the transaction.	"af051c4d..."
data	JSON	Blockchain-dependent data representation	{"id": "fdcbb4e...", "paging_token": "38112560532193280", "hash": "fdcbb4e...", "ledger": 8873772, "created_at": "2018-05-09T13:20:53Z", "source_account": "GAS5AL...", "source_account_sequence": "36978014856151081", "fee_paid": 100, "operation_count": 1, ...}
block_height	integer	Block number	8872466
block_time	ISO 8601	Validation time of the block which is represents the time the proof has been ultimately persisted	"2018-05-09T11:32:03Z"
explorer_url	URL	Points to a blockchain explorer transaction detail page	https://testnet.steexp.com/tx/642b07917...8cc4123a970b6
network_name	string	High level name of the concrete blockchain network	"Stellar Testnet"
network_id	string or integer	Internal identifier for the network which lies within the scope of the concrete blockchain family. It can take multiple forms depending on the blockchain.	"cee0302d59844d32b...a37abedf28ecd472"

PDF Generation

Generate a custom proof of existence certificate PDF.

Endpoint

https://api.qed.digital/v1/reports/<slug>/pdf

cURL example

curl -X POST \
    https://api.qed.digital/v1/reports/<slug>/pdf/
    -H 'Authorization: app-token l1MttwRc4SJcuQwDabcDFF23noLjgEyUFmWZZZIgCVekwlOmBmGtDtaEvxJHBuM3' \
    -d '{
        "i18n": {...} // See below for full set of i18n options
        "address": "Immoweb s.a., Avenue Général Dumonceau, 56, B-1190 Forest, Belgium" // Address field
        "online_check": <URL TO SHA256 ONLINE VALIDATION TOOL> // defaults to https://emn178.github.io/online-tools/sha256_checksum.html
        "logo_url": "http://example.com/logo.png"  // Please make sure that the image is scaled appropriately
    }'

i18n Parameters

Key	Description	Default
certificate	Document title	"Certificate of Existence"
description	Brief description	"This certificate documents the existence of a file on the blockchain."
details	translatable text	"Details"
encryption	Encryption explanation text	"The checksum of the file was generated using the cryptographic hash function SHA256 (Secure Hash Algorithm 256)"
check_tx	translatable text	"Check the transaction"
download_hint	translatable text	"The file can be downloaded here"
verify_hint	translatable text	"To verify the file manually you can use this tool to generate a checksum and compare to the hash stored on the blockchain"
no_file	translatable text	"The file was stored outside of the scope of the service. The creator is responsible for providing the original data for evidence.
i18n_blockchain_data	translatable text	"Blockchain data"
i18n_block_number	translatable text	"Block no."
i18n_block_date	translatable text	"Block date"
i18n_file_hash	translatable text	"File hash"
i18n_sender_account	translatable text	"Sender account"
i18n_network_id	translatable text	"Network ID"
i18n_network_name	translatable text	"Network name"
i18n_transaction_id	translatable text	"Transaction ID"