Methods and systems for encoding digital information in nucleic acid (e.g., deoxyribonucleic acid) molecules without base-by-base synthesis, by encoding bit-value information in the presence or absence of unique nucleic acid sequences within a pool, comprising specifying each bit location in a bit-stream with a unique nucleic sequence and specifying the bit value at that location by the presence or absence of the corresponding unique nucleic acid sequence in the pool But, more generally, specifying unique bytes in a bytestream by unique subsets of nucleic acid sequences. Also disclosed are methods for generating unique nucleic acid sequences without base-by-base synthesis using combinatorial genomic strategies (e.g., assembly of multiple nucleic acid sequences or enzymatic-based editing of nucleic acid sequences).