{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://in-toto.io/schemas/v1/attestation.json",
  "title": "in-toto Attestation Statement",
  "description": "Schema for the in-toto Attestation Framework Statement structure. A Statement is a verifiable claim about one or more software subjects. It consists of a fixed lightweight envelope with a subject (the artifact being described) and a predicate (the claim about that subject). Common predicate types include SLSA Provenance, SPDX SBOM, and Vulnerability Scan results.",
  "type": "object",
  "required": ["_type", "subject", "predicateType", "predicate"],
  "properties": {
    "_type": {
      "type": "string",
      "const": "https://in-toto.io/Statement/v1",
      "description": "URI identifying this document as an in-toto Attestation Framework Statement v1."
    },
    "subject": {
      "type": "array",
      "description": "One or more software artifacts that this statement applies to. Each subject is identified by name and cryptographic digest.",
      "minItems": 1,
      "items": {
        "$ref": "#/$defs/Subject"
      }
    },
    "predicateType": {
      "type": "string",
      "format": "uri",
      "description": "URI that identifies the schema and semantics of the predicate. Well-known values include https://slsa.dev/provenance/v1 and https://spdx.dev/Document."
    },
    "predicate": {
      "type": "object",
      "description": "The claim about the subjects. The structure is defined by the predicateType URI. May describe provenance, vulnerability scan results, test results, code review, or any other supply chain assertion.",
      "additionalProperties": true
    }
  },
  "$defs": {
    "Subject": {
      "type": "object",
      "description": "A single software artifact that is the subject of this attestation, identified by name and one or more cryptographic digests.",
      "required": ["name", "digest"],
      "properties": {
        "name": {
          "type": "string",
          "description": "Human-readable name for the artifact. For files, this is typically a path or filename. For container images, this is typically an image reference without a digest."
        },
        "digest": {
          "$ref": "#/$defs/DigestSet"
        }
      }
    },
    "DigestSet": {
      "type": "object",
      "description": "A set of cryptographic digests for an artifact, keyed by hash algorithm name. At least one digest must be present.",
      "minProperties": 1,
      "properties": {
        "sha256": {
          "type": "string",
          "pattern": "^[a-fA-F0-9]{64}$",
          "description": "SHA-256 hex digest."
        },
        "sha512": {
          "type": "string",
          "pattern": "^[a-fA-F0-9]{128}$",
          "description": "SHA-512 hex digest."
        },
        "sha1": {
          "type": "string",
          "pattern": "^[a-fA-F0-9]{40}$",
          "description": "SHA-1 hex digest. Use is discouraged for new attestations."
        },
        "gitCommit": {
          "type": "string",
          "pattern": "^[a-fA-F0-9]{40}$",
          "description": "Full Git commit SHA-1 hash identifying a specific commit."
        }
      },
      "additionalProperties": {
        "type": "string",
        "description": "Digest value for an alternate algorithm."
      }
    },
    "SLSAProvenancePredicate": {
      "type": "object",
      "description": "SLSA Provenance predicate (v1) describing how an artifact was built. Used with predicateType https://slsa.dev/provenance/v1.",
      "required": ["buildDefinition", "runDetails"],
      "properties": {
        "buildDefinition": {
          "type": "object",
          "description": "Describes the inputs to the build: the build type, external parameters, and resolved dependencies.",
          "required": ["buildType", "externalParameters"],
          "properties": {
            "buildType": {
              "type": "string",
              "format": "uri",
              "description": "URI identifying the build system type and the schema for externalParameters."
            },
            "externalParameters": {
              "type": "object",
              "description": "The parameters that were supplied by the caller of the build system. Structure depends on the buildType.",
              "additionalProperties": true
            },
            "internalParameters": {
              "type": "object",
              "description": "Parameters set by the build system itself, not controllable by the caller.",
              "additionalProperties": true
            },
            "resolvedDependencies": {
              "type": "array",
              "description": "External artifacts that influenced the build and are not explicitly listed in externalParameters.",
              "items": {
                "$ref": "#/$defs/ResourceDescriptor"
              }
            }
          }
        },
        "runDetails": {
          "type": "object",
          "description": "Details specific to this particular execution of the build.",
          "required": ["builder"],
          "properties": {
            "builder": {
              "type": "object",
              "description": "The build system that produced this attestation.",
              "required": ["id"],
              "properties": {
                "id": {
                  "type": "string",
                  "format": "uri",
                  "description": "URI identifying the builder."
                },
                "version": {
                  "type": "object",
                  "description": "Version information for components of the builder.",
                  "additionalProperties": {
                    "type": "string"
                  }
                },
                "builderDependencies": {
                  "type": "array",
                  "description": "Artifacts that the builder used that are not part of the build definition.",
                  "items": {
                    "$ref": "#/$defs/ResourceDescriptor"
                  }
                }
              }
            },
            "metadata": {
              "type": "object",
              "description": "Metadata about this build run.",
              "properties": {
                "invocationId": {
                  "type": "string",
                  "description": "Unique identifier for this build invocation."
                },
                "startedOn": {
                  "type": "string",
                  "format": "date-time",
                  "description": "Timestamp when the build started."
                },
                "finishedOn": {
                  "type": "string",
                  "format": "date-time",
                  "description": "Timestamp when the build finished."
                }
              }
            },
            "byproducts": {
              "type": "array",
              "description": "Additional artifacts produced by the build that are not the primary output.",
              "items": {
                "$ref": "#/$defs/ResourceDescriptor"
              }
            }
          }
        }
      }
    },
    "ResourceDescriptor": {
      "type": "object",
      "description": "A reference to a software artifact used as input to or produced by a build. Includes a URI and optional digest and annotations.",
      "properties": {
        "uri": {
          "type": "string",
          "format": "uri",
          "description": "URI identifying the resource."
        },
        "digest": {
          "$ref": "#/$defs/DigestSet"
        },
        "name": {
          "type": "string",
          "description": "Semver or local name used to reference this resource within the build definition."
        },
        "downloadLocation": {
          "type": "string",
          "format": "uri",
          "description": "URI where this resource can be downloaded."
        },
        "mediaType": {
          "type": "string",
          "description": "MIME type of the resource."
        },
        "annotations": {
          "type": "object",
          "description": "Additional key-value metadata about the resource.",
          "additionalProperties": true
        }
      }
    }
  }
}