CCM_B0_SIZE
memcpy(b0, iv, CCM_B0_SIZE);
*(uint16_t *)(b0 + CCM_B0_SIZE) = htobe16(crp->crp_aad_length);
b0_len = CCM_B0_SIZE;
dst += CCM_B0_SIZE;
if (b0_len > CCM_B0_SIZE) {
KASSERT(b0_len - CCM_B0_SIZE == CCM_AAD_FIELD_SIZE,