One embodiment of the present invention provides a system that facilitates
confirmation of data communicated to a first device belonging to a first
user from a second device belonging to a second user. During operation,
the first device receives a message containing data from the second
device. The first device then translates the data into a string of words
(such as a human-friendly representation using a well-known function such
as the One Time Password (OTP) dictionary defined in IETF RFC 1938) that
can be recognized by a human. Next, the first device displays the string
of words to the first user. The second device also translates the
original data using the same well-known function. The first user and the
second user then confirm that both strings of words match. The
confirmation process is performed through a separate communication
channel. This confirmation process ensures that the data sent by the
second device is successfully received by the first device, and that it
was sent by the second device. That is, this confirmation process
provides both integrity checking and authentication on the data sent from
the second device to the first device.