asn1_error_t asn1_decode(uint8_t *asn1_data, size_t asn1_len, uint8_t *elem_tag, size_t *elem_len, uint8_t **elem_data){

	uint8_t *asn1_current = asn1_data;
	// return tag value
	*elem_tag = *asn1_current++;

	// compute element size
	*elem_len = 0;
	uint8_t byte_2nd = *asn1_current++;
	if((byte_2nd>>7) & 1) {
		// if bit 7 of byte set, this is a length of size
		uint8_t size_len = byte_2nd & 0x7f;
		if(size_len > 3) return ASN1_ARCH_BAD_LEN;		// if seq len > u24, we can't really handle this on calc
		rmemcpy(elem_len, asn1_current, size_len);
		asn1_current += size_len;
	}
	else *elem_len = byte_2nd;		// else size byte

	if(*elem_len > asn1_len) return ASN1_EOF;

	// return ptr to data start
	*elem_data = asn1_current;
	return ASN1_OK;

	// pull out tag with associated flags
	// node_o->tag = tag & 0b11111;
	// node_o->f_constr = (tag>>5 & 1);
	// node_o->f_class = (tag>>6 & 0b11);
}