adiantum_enc
adiantum_enc(buf + i, buf + i, SECSIZE, blkno, 16, &C);
void adiantum_enc(void *, const void *, size_t, const void *, size_t,
adiantum_enc(buf, C[i].p, C[i].len, C[i].t, C[i].tlen, &A);
adiantum_enc(dst, src, nbytes, blkno, tweaklen, A);