Endorsement policies are used to instruct a peer on how to decide whether a transaction is properly endorsed. When a peer receives a transaction, it invokes the VSCC (Validation System Chaincode) associated with the transaction’s Chaincode as part of the transaction validation flow to determine the validity of the transaction. Recall that a transaction contains one or more endorsement from as many endorsing peers. VSCC is tasked to make the following determinations:
- all endorsements are valid (i.e. they are valid signatures from valid certificates over the expected message)
- there is an appropriate number of endorsements
- endorsements come from the expected source(s)
Endorsement policies are a way of specifying the second and third points.
Endorsement policy syntax in the CLI¶
In the CLI, a simple language is used to express policies in terms of boolean expressions over principals.
A principal is described in terms of the MSP that is tasked to validate
the identity of the signer and of the role that the signer has within
that MSP. Four roles are supported: member, admin, client, and peer.
Principals are described as
MSP is the MSP
ID that is required, and
ROLE is one of the four strings
peer. Examples of valid principals are
'Org0.admin' (any administrator of the
Org0 MSP) or
'Org1.member' (any member of the
'Org1.client' (any client of the
Org1 MSP), and
'Org1.peer' (any peer of the
The syntax of the language is:
EXPR is either
OR, representing the two boolean
E is either a principal (with the syntax described
above) or another nested call to
- For example:
AND('Org1.member', 'Org2.member', 'Org3.member')requests 1 signature from each of the three principals
OR('Org1.member', 'Org2.member')requests 1 signature from either one of the two principals
OR('Org1.member', AND('Org2.member', 'Org3.member'))requests either one signature from a member of the
Org1MSP or 1 signature from a member of the
Org2MSP and 1 signature from a member of the
Specifying endorsement policies for a chaincode¶
Using this language, a chaincode deployer can request that the endorsements for a chaincode be validated against the specified policy.
if not specified at instantiation time, the endorsement policy defaults to “any member of the organizations in the channel”. For example, a channel with “Org1” and “Org2” would have a default endorsement policy of “OR(‘Org1.member’, ‘Org2.member’)”.
The policy can be specified at instantiate time using the
followed by the policy.
peer chaincode instantiate -C <channelid> -n mycc -P "AND('Org1.member', 'Org2.member')"
This command deploys chaincode
mycc with the policy
'Org2.member') which would require that a member of both Org1 and Org2 sign
Notice that, if the identity classification is enabled (see Membership Service Providers (MSP)), one can use the PEER role to restrict endorsement to only peers.
peer chaincode instantiate -C <channelid> -n mycc -P "AND('Org1.peer', 'Org2.peer')"
A new organization added to the channel after instantiation can query a chaincode (provided the query has appropriate authorization as defined by channel policies and any application level checks enforced by the chaincode) but will not be able to commit a transaction endorsed by it. The endorsement policy needs to be modified to allow transactions to be committed with endorsements from the new organization (see Upgrade and Invoke Chaincode).