A semiconductor storage device having a security function for imposing
limitation on data rewriting includes: at least one non-volatile memory
cell array block which is capable of receiving concurrent electrical
erasure; at least one memory region, each one of said at least one memory
region being provided in the at least one memory cell array block, for
storing a security release key; at least one non-volatile storage means
for storing a security registration lock corresponding to each of the at
least one memory cell array block; a determination circuit for generating
a security release signal using the security release key and the security
registration lock; and a memory cell array data output switching circuit
for outputting security released data externally.