Weighted multiple authorizations

A computer-readable storage medium storing an authorization specification comprising:

• a root node with a threshold weight;
• and
• child nodes of non-leaf nodes, each child node having
• an authority weight,
• when a child node is a leaf node, signature verification information of an authority, and
• when a child node is a non-leaf node, a threshold weight.

A computer system for confirming an authorization based on multiple signatures, the computer system comprising:

• one or more computer-readable storage mediums storing
• an authorization specification represented as a tree having
• a root node with a threshold weight;
• and
• child nodes of non-leaf nodes, each child node having an authority weight, and when a child node is a leaf node, having signature verification information of an authority, and when a child node is a non-leaf node, having a threshold weight;
• signatures of at least some of the authorities;
• and
• computer-executable instructions that:
• for signatures of an authorities, verify the signature using the signature verification information of the authority;
• for each set of sibling nodes,
• sum the authority weights of zero or more sibling nodes that are leaf nodes and have verified signatures of their authorities and sum the authority weights of zero or more non-leaf nodes whose threshold weight is satisfied by the authority weights of their child nodes;
• and
• when the sum of the authority weights satisfies the threshold weight of the parent node of the sibling nodes, indicate that the threshold weight of the parent node is satisfied;
• when the threshold weight of the root node is indicated as being satisfied, indicate that the authorization has been confirmed;
• and
• one or more processors for executing the computer-executable instructions stored in the one or more computer-readable storage mediums.

A method performed by a computing system for confirming an authorization, the method comprising:

• accessing a Boolean expression of an authorization specification based on authorities, wherein the Boolean expression does not represent a threshold number of authorizations out of equal authorizations;
• accessing an indication of verified authorizations of the authorities;
• for each authority whose authorization is verified, setting its value to true;
• for each authority whose authorization is not verified,
• setting its value to false;
• evaluating the Boolean expression based on the setting;
• and
• indicating that the authorization is confirmed when the Boolean expression evaluates to true.

A method performed by a computing system for confirming an authorization based on multiple signatures, the method comprising:

• accessing an authorization specification that specifies signature verification that specifies a first signature based on a first signature algorithm and a second signature based on a second signature algorithm;
• verifying a first signature using the first signature algorithm;
• verifying a second signature using the second signature algorithm;
• and
• indicating that authorization has been confirmed based on the verifications.