Verifying a rebuilt encoded data slice using slice verification information

A computer readable storage medium comprises:

• at least one memory section that stores operational instructions that, when executed by one or more processing modules of a storage network that include a processor, causes the one or more processing modules to:
• receive an encoded data slice of a set of encoded data slices for storage;
• receive a set of integrity values corresponding to the set of encoded data slices, the set of integrity values generated by performing a first integrity function on each of the encoded data slices of the set of encoded data slices;
• perform a second integrity function on the set of integrity values to produce a calculated integrity value of the set of integrity values;
• indicate that the set of integrity values are validated when the calculated integrity value matches a locally stored integrity value;
• perform the first integrity function on the received encoded data slice to produce a calculated integrity value of the received encoded data slice;
• and
• indicate that the received encoded data slice is valid when the calculated integrity value of the received encoded data slice matches a corresponding integrity value of the validated set of integrity values.

A computing device of a storage network, the computing device comprises:

• a network interface;
• local memory;
• and
• a processing module operably coupled to the network interface and the local memory, wherein the processing module operates to:
• receive, via the network interface, an encoded data slice of a set of encoded data slices for storage;
• receive, via the network interface, a set of integrity values corresponding to the set of encoded data slices, the set of integrity values generated by performing a first integrity function on each of the encoded data slices of the set of encoded data slices;
• perform a second integrity function on the set of integrity values to produce a calculated integrity value of the set of integrity values;
• indicate that the set of integrity values are validated when the calculated integrity value matches a locally stored integrity value;
• perform the first integrity function on the received encoded data slice to produce a calculated integrity value of the received encoded data slice;
• and
• indicate that the received encoded data slice is valid when the calculated integrity value of the received encoded data slice matches a corresponding integrity value of the validated set of integrity values.