The invention relates to a method and a system for detecting errors in the
communication of data from a transmitter to at least one receiver. In the
method, in a first step on the side of the transmitter a first check
value is generated at least from user data to be communicated; in a
second step on the side of the transmitter a second check value is
generated at least from the user data and the first check value; in a
third step at least the user data, the first check value and the second
check value are communicated to the receiver; in a fourth step on the
side of the receiver the communicated user data and the communicated
first check value are verified with the aid of the second check value;
and in a fifth step on the side of the receiver the communicated user
data are verified with the aid of the first check value. To improve the
detection of errors in the communication of data from the transmitter to
the at least one receiver it is proposed that, in the first step, the
user data are modified to generate the first check value, in the second
step the unmodified user data are used to generate the second check
value, in the fourth step the unmodified communicated user data are used,
and in the fifth step the communicated user data are modified according
to the modification in the first step for checking with the aid of the
first check value.