msp.go

/*
Copyright IBM Corp. 2016 All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

		 http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package msp

import (
	"github.com/hyperledger/fabric/protos/msp"
)

// FIXME: we need better comments on the interfaces!!
// FIXME: we need better comments on the interfaces!!
// FIXME: we need better comments on the interfaces!!

// IdentityDeserializer is implemented by both MSPManger and MSP
type IdentityDeserializer interface {
	// DeserializeIdentity deserializes an identity.
	// Deserialization will fail if the identity is associated to
	// an msp that is different from this one that is performing
	// the deserialization.
	DeserializeIdentity(serializedIdentity []byte) (Identity, error)
}

// Membership service provider APIs for Hyperledger Fabric:
//
// By "membership service provider" we refer to an abstract component of the
// system that would provide (anonymous) credentials to clients, and peers for
// them to participate in Hyperledger/fabric network. Clients use these
// credentials to authenticate their transactions, and peers use these credentials
// to authenticate transaction processing results (endorsements). While
// strongly connected to the transaction processing components of the systems,
// this interface aims to have membership services components defined, in such
// a way such that alternate implementations of this can be smoothly plugged in
// without modifying the core of transaction processing components of the system.
//
// This file includes Membership service provider interface that covers the
// needs of a peer membership service provider interface.

// MSPManager is an interface defining a manager of one or more MSPs. This
// essentially acts as a mediator to MSP calls and routes MSP related calls
// to the appropriate MSP.
// This object is immutable, it is initialized once and never changed.
type MSPManager interface {

	// IdentityDeserializer interface needs to be implemented by MSPManager
	IdentityDeserializer

	// Setup the MSP manager instance according to configuration information
	Setup(msps []MSP) error

	// GetMSPs Provides a list of Membership Service providers
	GetMSPs() (map[string]MSP, error)
}

// MSP is the minimal Membership Service Provider Interface to be implemented
// to accommodate peer functionality
type MSP interface {

	// IdentityDeserializer interface needs to be implemented by MSP
	IdentityDeserializer

	// Setup the MSP instance according to configuration information
	Setup(config *msp.MSPConfig) error

	// GetType returns the provider type
	GetType() ProviderType

	// GetIdentifier returns the provider identifier
	GetIdentifier() (string, error)

	// GetSigningIdentity returns a signing identity corresponding to the provided identifier
	GetSigningIdentity(identifier *IdentityIdentifier) (SigningIdentity, error)

	// GetDefaultSigningIdentity returns the default signing identity
	GetDefaultSigningIdentity() (SigningIdentity, error)

	// GetRootCerts returns the root certificates for this MSP
	GetRootCerts() []Identity

	// GetIntermediateCerts returns the intermediate root certificates for this MSP
	GetIntermediateCerts() []Identity

	// Validate checks whether the supplied identity is valid
	Validate(id Identity) error

	// SatisfiesPrincipal checks whether the identity matches
	// the description supplied in MSPPrincipal. The check may
	// involve a byte-by-byte comparison (if the principal is
	// a serialized identity) or may require MSP validation
	SatisfiesPrincipal(id Identity, principal *msp.MSPPrincipal) error
}

// OUIdentifier represents an organizational unit and
// its related chain of trust identifier.
type OUIdentifier struct {
	// CertifiersIdentifier is the hash of certificates chain of trust
	// related to this organizational unit
	CertifiersIdentifier []byte
	// OrganizationUnitIdentifier defines the organizational unit under the
	// MSP identified with MSPIdentifier
	OrganizationalUnitIdentifier string
}

// From this point on, there are interfaces that are shared within the peer and client API
// of the membership service provider.

// Identity interface defining operations associated to a "certificate".
// That is, the public part of the identity could be thought to be a certificate,
// and offers solely signature verification capabilities. This is to be used
// at the peer side when verifying certificates that transactions are signed
// with, and verifying signatures that correspond to these certificates.///
type Identity interface {

	// GetIdentifier returns the identifier of that identity
	GetIdentifier() *IdentityIdentifier

	// GetMSPIdentifier returns the MSP Id for this instance
	GetMSPIdentifier() string

	// Validate uses the rules that govern this identity to validate it.
	// E.g., if it is a fabric TCert implemented as identity, validate
	// will check the TCert signature against the assumed root certificate
	// authority.
	Validate() error

	// GetOrganizationalUnits returns zero or more organization units or
	// divisions this identity is related to as long as this is public
	// information. Certain MSP implementations may use attributes
	// that are publicly associated to this identity, or the identifier of
	// the root certificate authority that has provided signatures on this
	// certificate.
	// Examples:
	//  - if the identity is an x.509 certificate, this function returns one
	//    or more string which is encoded in the Subject's Distinguished Name
	//    of the type OU
	// TODO: For X.509 based identities, check if we need a dedicated type
	//       for OU where the Certificate OU is properly namespaced by the
	//       signer's identity
	GetOrganizationalUnits() []*OUIdentifier

	// Verify a signature over some message using this identity as reference
	Verify(msg []byte, sig []byte) error

	// Serialize converts an identity to bytes
	Serialize() ([]byte, error)

	// SatisfiesPrincipal checks whether this instance matches
	// the description supplied in MSPPrincipal. The check may
	// involve a byte-by-byte comparison (if the principal is
	// a serialized identity) or may require MSP validation
	SatisfiesPrincipal(principal *msp.MSPPrincipal) error
}

// SigningIdentity is an extension of Identity to cover signing capabilities.
// E.g., signing identity should be requested in the case of a client who wishes
// to sign transactions, or fabric endorser who wishes to sign proposal
// processing outcomes.
type SigningIdentity interface {

	// Extends Identity
	Identity

	// Sign the message
	Sign(msg []byte) ([]byte, error)

	// GetPublicVersion returns the public parts of this identity
	GetPublicVersion() Identity
}

// IdentityIdentifier is a holder for the identifier of a specific
// identity, naturally namespaced, by its provider identifier.
type IdentityIdentifier struct {

	// The identifier of the associated membership service provider
	Mspid string

	// The identifier for an identity within a provider
	Id string
}

// ProviderType indicates the type of an identity provider
type ProviderType int

// The ProviderType of a member relative to the member API
const (
	FABRIC ProviderType = iota // MSP is of FABRIC type
	OTHER                      // MSP is of OTHER TYPE
)