Securely extensible component meta-data

1. A computer-implemented method of updating meta-data associated with a component, wherein the meta-data includes a plurality of meta-data elements, the method comprising:

verifying signatures associated with the component meta-data;

accepting a first meta-data supplement comprising a plurality of meta-data elements;

verifying signatures associated with the first meta-data supplement;

authenticating the first meta-data supplement; and

updating the meta-data elements associated with the component with values of the plurality of meta-data elements associated with the first meta-data supplement;

accepting a second meta-data supplement comprising a second plurality of meta-data elements;

verifying signatures associated with the second meta-data supplement;

authenticating the second meta-data supplement;

sorting the first and second meta-data supplements to provide a sorted plurality of meta-data supplements, each meta-data supplement including a time stamp and sorting the first and second meta-data supplements comprising sorting the meta-data supplements according to the time stamps;

updating the meta-data associated with the component with values of corresponding meta-data elements from the sorted meta-data supplements; and

verifying, by a computer, compatibility between meta-data associated with a component and a meta-data supplement by determining that like-named meta-data elements associated with the component and the meta-data supplement have compatible types and compatible mutability attributes.

2. A computer-implemented method for use with digital components, the method comprising:

accepting a digital component the digital component comprising content and component meta-data;

accepting a first meta-data supplement, the first meta-data supplement comprising first target meta-data and first supplement meta-data;

updating the component meta-data with the first target meta-data;

determining whether the component meta-data is mutable; and

determining whether the target meta-data is compatible with the component meta-data, wherein the component meta-data and target meta-data each comprise a plurality of meta-data elements having an associated name, type, value, and mutability attribute, and wherein determining whether the target meta-data is compatible with the component meta-data comprises performance of the following by a computer:

selecting a first meta-data element from the target meta-data;

determining whether the component meta-data includes a like-named meta-data element;

determining whether the first meta-data element and the like-named meta-data element have compatible mutability attributes; and

determining whether the first meta-data element and the like-named meta-data element have compatible types.

3. The method of claim 2 wherein the component meta-data includes a first meta-data signature and the target meta-data includes a second meta-data signature, the method further comprising:

verifying the first and second meta-data signatures; and

updating the component meta-data with the first target meta-data only if the meta-data signature are successfully verified and the first and second meta-data signatures are from the same signer.

4. The method of claim 3 wherein the first and second meta-data signatures comprising digital signatures using public key cryptography.