1. A method for generating a digest in a transactional memory environment for performing transactional executions, wherein memory store data of a transaction are committed to memory at transaction completion, the transactional memory environment supporting transaction nesting, the method comprising: generating for a transaction, by a computer system configured to execute the transaction, a computed digest based on the execution of at least one of a plurality of instructions of the transaction; based on beginning a nested transaction, executed within a transactional region of the transaction, saving a snapshot of the computed digest as a nesting level snapshot; beginning execution of the nested transaction; updating, by the computer system, the computed digest based on the execution of at least one of a plurality of instructions of the nested transaction; and based on an abort of the nested transaction, restoring the computed digest from the nesting level snapshot and restarting the nested transaction.