A method, system and computer program product for reducing the amount of helper data that needs to be stored using two innovative techniques. The first technique uses bit-error-rate (BER)-aware lossy compression. By treating a fraction of reliable bits as unreliable, it effectively reduces the size of the reliability mask. With the view of practical costs of production-time error characterization, the second technique enables economically feasible across-temperature per-bit BER evaluation for use in a number of fuzzy extractor optimizations based on bit-selection to reduce overall BER (with or without subsequent compression) using room-temperature only production-time characterization. The technique is based on stochastic concentration theory and allows efficiently forming confidence intervals for average across-temperature BER of a selected set of bits. By using these techniques, it is economically feasible to achieve a dramatic reduction in the amount of helper data that needs to be stored in non-volatile memory and/or one-time-programmable memory.