A method of embedding an additional layer of error correction into an
error correcting code, where information is encoded into code words that
are arranged in columns of a code block. The method includes reducing the
length of each row of the code block by adding row symbols together
according to a predetermined adding rule resulting in a reduced code
block; encoding the shortened rows of the reduced code block using a
horizontal error correcting code to obtain horizontal parities; and
embedding the horizontal parities as additional layer in the error
correcting code.