1. A secure computing method, comprising: storing a set of precomputed, encrypted reference signatures for a plurality of basic blocks of an executable program in a first memory; during execution of the executable program, retrieving a respective basic block of the executable program from a second memory; partially processing instructions of the respective basic block of the executable program in a multistage instruction processing pipeline, and concurrently computing a signature of the instructions with a signature generator, to generate a signature for the respective basic block of instructions along an execution path of the instructions; if (a) an instruction terminating an execution path of the instructions of the respective basic block of the executable program is pending completion, and (b) a decrypted reference signature of the respective basic block is available in a signature cache, then: verifying the signature for the respective basic block against the decrypted reference signature; else: stalling commitment of the instruction terminating the execution path of the instructions of the respective basic block of the executable program; securely decrypting the encrypted reference signature; storing the decrypted encrypted reference signature in the signature cache as the decrypted reference signature; and verifying the signature for the respective basic block against the decrypted reference signature; and if verifying of the signature for the respective basic block against the decrypted reference signature is successful, permitting commitment of the instruction terminating the execution path of the instructions of the respective basic block of the executable program, else preventing commitment of the instruction terminating the execution path of the instructions of the respective basic block of the executable program.