1. A method of encrypting and decrypting digital data such as text, numeric, images, pictures, especially tailored for optical compact discs; said method comprises of ciphering/deciphering and error detection and correction using algebraic method, namely Reed-Solomon code; said method characterised by the following steps: A. choose a primitive polynomial p(x) over Galois Field (GF) according to CD-standards; B. consider the data structure which are the values of different polynomials in said GF EQU D=(d.sub.1, d.sub.2, d.sub.3,. .. d.sub.n) n is multiple of m; C. select a key EQU K=(k.sub.1, k.sub.2, k.sub.3,. .. , k.sub.m); D. generate a matrix of random variable EQU R=(r.sub.ij) i=1,2,3,. .. ,m; j=1,2,3. .. ,m; E. calculate the encryption vector EQU C=K.sunburst.R .sunburst. is multiplication over said GF=c.sub.i i=1,2,3,. .. ,m; F. enciphering the data EQU E=D+C + is addition over said GF=e.sub.ij i=1,2,3,. .. ,m; j=1,2,3,. .. ,n G. apply scrambling of depth s EQU E.fwdarw.E' EQU e.sub.ij .fwdarw.e'.sub.i+(j-1)s,j i=1,2,3,. .. n; j=1,2,3,. .. ns; s any positive integer; H. encode E' according to CD-encoding standards; I. the output from H above is the enciphered data which are the values of the polynomials over said GF to be sent to the EFM modulation; J. the decryption method comprises the following steps: decode the data according to the CD-standards to produce the ciphered data E'; descramble the ciphered data: E'.fwdarw.E; calculate the decryption vector: EQU C=K.sunburst.R .sunburst. is multiplication over said GF; add deciphering key to recover the original data: EQU D=E+C + is addition over said GF.