Messages

All data transferred over the aleph.im network are Aleph messages and represent the core of the Aleph networking model.

Messages can be:

• sent and received on the REST or other API interfaces

• exchanged on the peer-to-peer network

• stored on the underlying chains

Actual content sent by regular users can currently be of three types:

• AGGREGATE: a key-value storage specific to an address

• POST: unique data posts (unique data points, events)

• STORE: file storage

Message types

• Aggregates
• Forgets
• Posts
• Programs
• Stores

Item hash, type and content

Messages are uniquely identified by the item_hash field. This value is obtained by computing the hash of the content field. Currently, the hash can be obtained in one of two ways. If the content of the message is stored on IPFS, the item_hash of the message will be the CIDv0 of this content. Otherwise, if the message is stored on Aleph native storage or is included in the message, the item hash will be the SHA256 hash of the message in hexadecimal encoding. In the first case, the item type will be set to “ipfs”. In the second case, the item type will either be “inline” if the content is included in the message (serialized as a string in the item_content field) or “storage”. Inline storage will be used for content up to 200kB. Beyond this size, users must update the content prior to uploading the message on IPFS or Aleph storage.

Signature

Aleph messages are cryptographically signed with the private key of the user. The signature covers the sender, chain, type and item_hash fields of the message.