# Docs

The docs module is the one that allows you to send a document to another user, and retrieve the list of documents that you have received.

# Transactions

Using the docs module you can perform the following transactions.

Accessible to everyone

# Sending a document

In order to send a document you are required to have an identity with some tokens inside it.

TIP

To know what an identity is, how to create it and how to get tokens, please refer to the "Creating an identity" section.

# Transaction message

In order to properly send a transaction to share a document, you will need to create and sign the following message.

{
  "type": "commercio/MsgShareDocument",
  "value": {
    "sender": "<Sender Did>",
    "recipients": [
      "<Recipient did>"
    ],
    "uuid": "<Document UUID>",
    "content_uri": "<Document content URI>",
    "metadata": {
      "content_uri": "<Metadata content URI>",
      "schema": {
        "uri": "<Metadata schema definition URI>",
        "version": "<Metadata schema version>"
      },
      "schema_type": "<Metadata schema type>"
    },
    "checksum": {
      "value": "<Document content checksum value>",
      "algorithm": "<Document content checksum algorithm>"
    },
    "encryption_data": {
      "keys": [
        {
          "recipient": "<Recipient address>",
          "value": "<Encrypted and encoded symmetric key value>"
        }
      ],
      "encrypted_data": [
        "<Encrypted field identifier>"
      ]
    },
    "do_sign": {
        "storage_uri": "uri://storage",
        "signer_instance": "did S",
        "sdn_data": [
          "common_name",                
          "surname",                
          "serial_number",                
          "given_name",
          "organization",
          "country"
        ],
        "vcr_id": "<identity VCR Identifier",
        "certificate_profile": "<one of the profiles supported by S>"
    }
  }
}

# Fields requirements

Field	Required	Limit/Format
`sender`	Yes	bech32
`recipients`	Yes	bech32
`uuid`	Yes	uuid-v4 (opens new window)
`content_uri`	No *¹	512 bytes
`metadata`	Yes
`checksum`	No
`encryption_data`	No *¹
`do_sign`	No *¹

*¹ Must be omitted if empty.

# `metadata`

Field	Required	Limit/Format
`content_uri`	Yes	512 bytes
`schema_type`	No ¹ ² *³	512 bytes
`schema`	No *¹

*¹ The schema_type and schema fields are mutually exclusive. This means that if the first one exists the second will not be used.
*² You can read which schema_type values are supported inside the supported metadata schemes section
*³ Must be omitted if empty.

# `metadata.schema`

Field	Required	Limit/Format
`uri`	Yes	512 bytes
`version`	Yes	32 bytes

# `checksum`

Field	Required
`value`	Yes
`algorithm`	Yes *¹

*¹ You can read which checksum.algorithm values are supported inside the supported checksum algorithms section

# `encryption_data`

Field	Required	Limit/Format
`keys`	Yes
`encrypted_data`	Yes
`encryption_data.keys.*.value`	Yes	512 bytes

# `do_sign`

Field	Required	Limit/Format
`storage_uri`	Yes
`signer_instance`	Yes
`sdn_data`	No
`vcr_id`	Yes	64 bytes
`certificate_profile`	Yes	32 bytes

storage_uri
signer_instance
sdn_data: contains an array with a list of required fields for Subject Distinguish Name. The names of fields are x509 standard compliant

# Supported checksum algorithm

When computing the checksum of a document's contents, you must use one of the following supported checksum algorithms.
Not using one of these will result in your transaction being rejected or mishandled by recipients.

Algorithm	Specification
`md5`	MD5 (opens new window)
`sha-1`	SHA-1 (opens new window)
`sha-224`	RFC 4634 (opens new window)
`sha-256`	RFC 4634 (opens new window)
`sha-384`	RFC 4634 (opens new window)
`sha-512`	RFC 4634 (opens new window)

# Checksum validity check

Please note that, when sending a document that has an associated checksum, the validity of the checksum itself is checked only formally. This means that we only check that the hash value has a valid length, but we do not check if the given has is indeed the hash of the document's content. It should be the client responsibility to perform this check.

# Encrypting the data

TIP

The following is just an example on how to do file encryption, you're free to use any other algorithm!

In order to properly encrypting the data that you want to avoid being shared publicly, the following procedure should be followed.

We'll use AES-256 in CBC mode to encrypt a file, and let the recipient decrypt it by sharing with it the AES encryption key.

Generate a safe AES-256 encryption key. A key size of 256 bits is recommended.
```
aes_key = get_random_aes_key(key_size = 256)
```

Use the AES key to encrypt the data you desire using the AES-256 CBC method.

encrypted_data = aes_encrypt_cbc(
  key = aes_key, 
  initialization_vector = null
)

Encrypt the AES-256 key using the recipient's public encryption key

encrypted_aes_key = rsa_encrypt(
  key = recipient.public_rsa_encryption_key,
  value = aes_key
)

Encode the encrypted AES-256 key

encoded_encryption_key = hex_encode(encrypted_aes_key)

Compose the encryption data

{
  "encryption_data": {
    "keys": [
      {
        "recipient": "<Recipient address>",
        "value": "<Hex encoded encryption key>"
      }
    ],
    "encrypted_data": [
      "<Your encrypted data identifier>"
    ]
  }
}

The encrypted_data field does not contain the encrypted payload itself, but rather denotes what message property is encrypted with aes_key.

encrypted_data only accepts the following identifiers:

content_uri
metadata.content_uri
metadata.schema.uri

A special identifier, content, can be used to specify that aes_key has been used to encrypt a file exchanged by other means of communication.

# Supported encrypted data

Please note that when specifying which data you have encrypted for the document recipient, you need to use one or more of the following identifiers inside the encryption_data.encrypted_data field.
Inserting other non supported values inside such a field will result in the transactions being rejected as not valid.

Identifier	Referenced data
`content`	Document's file contents
`content_uri`	Value of the `content_uri` field
`metadata.content_uri`	Value of the `content_uri` field inside the `metadata` object
`metadata.schema.uri`	Value of the `uri` field inside the `metadata`'s `schema` sub-object

# Action type

If you want to list past transactions including this kind of message, you need to use the following message.action value:

shareDocument

# Sending a document reading receipt

Once you have received a document and you want to acknowledge the sender that you have properly read it, you can use the MsgSendDocumentReceipt message that allows you to do that.

# Transaction message

In order to properly send a transaction to send a document receipt, you will need to create and sign the following message.

{
  "type": "commercio/MsgSendDocumentReceipt",
  "value": {
    "uuid": "<Unique receipt identifier>",
    "sender": "<Receipt sender address: one of recipients of Document>",
    "recipient": "<Receipt recipient address: sender of Document>",
    "tx_hash": "<Tx hash in which the document has been sent>",
    "document_uuid": "<Document UUID>",
    "proof": "<Optional reading proof>"
  }
}

# Fields requirements

Field	Required	Limit/Format
`uuid`	Yes	uuid-v4 (opens new window)
`sender`	Yes	bech32
`recipient`	Yes	bech32
`tx_hash`	Yes
`document_uuid`	Yes	uuid-v4 (opens new window)
`proof`	No *¹

*¹ Must be omitted if empty.

proof is a generic field that can be used to prove some part of receipt correlated to documents and/or some other proof out of chain

# Action type

If you want to list past transactions including this kind of message, you need to use the following message.action value:

sendDocumentReceipt

# Queries

# List sent documents

# CLI

cncli query docs sent-documents [address]

# REST

/docs/{address}/sent

Parameters:

Parameter	Description
`address`	Address of the user for which to read current sent documents

# Example

Getting sent docs from did:com:12p24st9asf394jv04e8sxrl9c384jjqwejv0gf:

http://localhost:1317/docs/did:com:12p24st9asf394jv04e8sxrl9c384jjqwejv0gf/sent

# List received documents

# CLI

cncli query docs received-documents [address]

# REST

/docs/{address}/received

Parameters:

Parameter	Description
`address`	Address of the user for which to read current received documents

# Example

Getting docs for did:com:12p24st9asf394jv04e8sxrl9c384jjqwejv0gf:

http://localhost:1317/docs/did:com:12p24st9asf394jv04e8sxrl9c384jjqwejv0gf/received

# List sent receipts

# CLI

cncli query docs sent-receipts [address]

# REST

/receipts/{address}/sent

Parameters:

Parameter	Description
`address`	Address of the user for which to read current sent recepits

# Example

Getting sent receipts from did:com:12p24st9asf394jv04e8sxrl9c384jjqwejv0gf:

http://localhost:1317/receipts/did:com:12p24st9asf394jv04e8sxrl9c384jjqwejv0gf/sent

# List received receipts

# CLI

cncli query docs received-receipts [address]

# REST

/receipts/{address}/received

Parameters:

Parameter	Description
`address`	Address of the user for which to read current received documents

# Example

Getting recepits for did:com:12p24st9asf394jv04e8sxrl9c384jjqwejv0gf:

http://localhost:1317/recepits/did:com:12p24st9asf394jv04e8sxrl9c384jjqwejv0gf/received

← Id CommercioMint →

# Docs

# Transactions

# Sending a document

# Transaction message

# Fields requirements

# metadata

# metadata.schema

# checksum

# encryption_data

# do_sign

# Supported checksum algorithm

# Checksum validity check

# Encrypting the data

# Supported encrypted data

# Action type

# Sending a document reading receipt

# Transaction message

# Fields requirements

# Action type

# Queries

# List sent documents

# CLI

# REST

# Example

# List received documents

# CLI

# REST

# Example

# List sent receipts

# CLI

# REST

# Example

# List received receipts

# CLI

# REST

# Example

# `metadata`

# `metadata.schema`

# `checksum`

# `encryption_data`

# `do_sign`