Interface CompositeKey

 All Implemented Interfaces:

java.io.Serializable
,java.security.Key
,java.security.PublicKey
public interface CompositeKey implements PublicKey
A tree data structure that enables the representation of composite public keys, which are used to represent the signing requirements for multisignature scenarios. A composite key is a list of leaf keys and their contributing weight, and each leaf can be a conventional single key or a composite key. Keys contribute their weight to the total if they are matched by the signature.
For complex scenarios, such as "Both Alice and Bob need to sign to consume a state S", we can represent the requirement by creating a tree with a root CompositeKey, and
Alice
andBob
as children. The root node would specify weights for each of its children and a threshold – the minimum total weight required (for example, the minimum number of child signatures required) to satisfy the tree signature requirement.Using these constructs we can express, for example, 1 of N (OR) or N of N (AND) signature requirements. By nesting we can create multilevel requirements such as "either the CEO or three of five of his assistants need to sign".
Composite key implementations will track the minimum total weight required (in the simple case – the minimum number of child signatures required) to satisfy the subtree rooted at this node.


Method Summary
Modifier and Type Method Description abstract void
checkValidity()
This method will detect graph cycles in the full composite key structure to protect against infinite loops when traversing the graph and key duplicates in each layer. abstract boolean
isFulfilledBy(@NotNull() PublicKey key)
Takes single PublicKey and checks if CompositeKey requirements hold for that key. abstract boolean
isFulfilledBy(@NotNull() Set<PublicKey> keysToCheck)
Checks if the public keys corresponding to the signatures are matched against the leaves of the composite key tree in question, and the total combined weight of all children is calculated for every intermediary node. abstract Set<PublicKey>
getLeafKeys()
Set of all leaf keys of that CompositeKey.



Method Detail

checkValidity
abstract void checkValidity()
This method will detect graph cycles in the full composite key structure to protect against infinite loops when traversing the graph and key duplicates in each layer. It also checks if the threshold and weight constraint requirements are met, while it tests for aggregatedweight integer overflow. In practice, this method should be always invoked on the root CompositeKey, as it inherently validates the child nodes (all the way till the leaves).

isFulfilledBy
abstract boolean isFulfilledBy(@NotNull() PublicKey key)
Takes single PublicKey and checks if CompositeKey requirements hold for that key.
 Parameters:
key
 The public key. Returns:
true if the public key is a composite key, false otherwise.

isFulfilledBy
abstract boolean isFulfilledBy(@NotNull() Set<PublicKey> keysToCheck)
Checks if the public keys corresponding to the signatures are matched against the leaves of the composite key tree in question, and the total combined weight of all children is calculated for every intermediary node. If all thresholds are satisfied, the composite key requirement is considered to be met.

getLeafKeys
@NotNull() abstract Set<PublicKey> getLeafKeys()
Set of all leaf keys of that CompositeKey.

