The invention discloses a data hiding method based on a Lagrange interpolation method and multiple clouds, which is applied in a
system under a multi-cloud environment. The
system comprises four parts: a user, a
client, a data uploading layer, a data downloading layer and the clouds; before data are uploaded, an information segmentation
algorithm of Reed Solomon erasure codes is used for segmenting the user data on the
client, the Lagrange interpolation method is then used for carrying out
information hiding on each block of segmented data, and finally, each block of data is stored in a different
cloud storage. During data downloading, the data only need to be obtained from part of the cloud storages, the Lagrange interpolation method is first used for carrying out hidden
information recovery on each block of data, and a
recovery algorithm in Reed Solomon is then used for merging the data blocks to recover the
original data. The data hiding method based on the Lagrange interpolation method and the multiple clouds solves the availability problem of services and the limitation of a single
cloud storage; while reducing storage spaces, the usage of the Reed Solomon
algorithm can tolerate the errors of the cloud storages; the usage of the Lagrange interpolation method solves the
confidentiality problem of data, protecting the privacy of user data.