Encoding

Default profile v4-balanced writes 313-nt strands. Each frame carries an address, payload and CRC-32; frames are scrambled, protected by an inner Reed-Solomon code and mapped two bits per base with in-strand synchronisation markers. Strands are screened for GC content, homopolymers, repeats and forbidden motifs; up to 256 scrambler variants are tried per frame. Profiles trade density for robustness (for example v7-lowcov adds outer parity for low coverage). Every strand frame has 14 bytes of header and CRC.