Aleo

Aleo is a blockchain platform built around privacy-preserving smart contracts. Unlike traditional blockchains where transaction data is publicly visible, Aleo uses zero-knowledge proofs (zk-SNARKs) to let users prove the correctness of a transaction — such as a token transfer or a contract execution — without revealing the underlying inputs.

Every Aleo transaction is accompanied by one of these proofs. Because generating a proof is a complex operation, Aleo is designed to allow delegation: a user can authorize a transaction and hand off the heavy proof-generation work to a third-party prover, without giving that prover access to their private key.

This delegation is what shapes the signing interface described below. Signing an Aleo transaction is not just a matter of producing a signature over a message — the signer must also compute certain values (such as input identifiers and a transition view key) that are needed by the prover to construct a valid proof.

Signing Interface

Two signing methods are supported: account signatures and delegated signing. Both accept a JSON request body and return a JSON response.

For full cryptographic detail, refer to the Aleo signature specification.

Input format

Both signing methods share the same top-level input structure:

Field	Type	Required	Description
`inputs`	array	Yes	One or more inputs to sign (see below)
`functionId`	string	Delegated only	Field element identifying the function being called
`isRoot`	boolean	Delegated only	Whether this is a root-level call
`checksum`	string	Delegated only(*)	Integrity checksum of the function. Omitted for older programs.

(*) Present only for programs that include a checksum.

Input types

Each entry in inputs has a type field and a data array of field elements (as decimal strings).

Type	Used in	Description
`account`	Account sig	Arbitrary message fields for account-level signing
`public`	Delegated	Publicly visible function input
`private`	Delegated	Encrypted function input
`record`	Delegated	A record commitment being consumed
`externalRecord`	Delegated	A record from an external program
`dynamicRecord`	Delegated	A dynamically referenced record

Examples

Account signature request

{
  "inputs": [
    {
      "type": "account",
      "data": [
        "6716502009016430053183507170699594817265084671791777241413633239014382669047",
        "1099471864310681484047468615352474858081227942590554598086745066318936376057"
      ]
    }
  ]
}

Delegated signing request

{
  "functionId": "7997765759116436245054600309458180601753471573319679234621276897246672782660",
  "isRoot": true,
  "checksum": "1503530553220993152536984095177360228202084361422343390783285383306871595686",
  "inputs": [
    {
      "type": "record",
      "data": [
        "3620054965614225011843835598412969685728959723873203421423497665637723824061",
        "4723421622337407625451130429846704556698341853293634966801114008038334673712"
      ]
    },
    {
      "type": "private",
      "data": [
        "2854583002587711767714127780974314920905498857787333885876654043294119228416",
        "166688728"
      ]
    },
    {
      "type": "private",
      "data": [
        "1237940039285380281610076208"
      ]
    }
  ]
}

Output format

All field element values are returned as decimal strings.

Field	Type	Present in	Description
`signature`	string	Both	Bech32m-encoded Schnorr signature (`sign1…`)
`tvk`	string	Delegated only	Transition view key (field element)
`tcm`	string	Delegated only	Transition commitment (field element)
`gammas`	array of strings	Delegated only	One gamma value per `record`-type input, in order

Account signature response

{
  "signature": "sign1g03t2q98yh7kets29s05en3ljp90umlhf5kwzhecsaalcxpffvqmnafyspdnmu42qjgj905f964yxl2ph7mz70dqy503xxyjj4rwxqur22qjwn4zc0pzv87twjygsz9m7ekljmuw4jpzf68rwuq99r0tp735vs6220q7tp60nr7llkwstcvu49wdhydx5x2s3sftjskzawhqvh8arjf"
}

Delegated signing response

{
  "signature": "sign1g03t2q98yh7kets29s05en3ljp90umlhf5kwzhecsaalcxpffvqmnafyspdnmu42qjgj905f964yxl2ph7mz70dqy503xxyjj4rwxqur22qjwn4zc0pzv87twjygsz9m7ekljmuw4jpzf68rwuq99r0tp735vs6220q7tp60nr7llkwstcvu49wdhydx5x2s3sftjskzawhqvh8arjf",
  "tvk": "6839744283125714768219049408772295603189719087890464618622056790088127041542",
  "tcm": "36661113237169170635146585844811003819221318715282919854177900780199067452",
  "gammas": [
    "4875506682083978504504607329729976086652196269888800393640799801065716748965"
  ]
}

The gammas array contains one entry per recordtype input, in the same order they appear in inputs. In the example above there is one record input, so gammas has one element.