Method and system for displaying program

The invention relates to a method and a system for playing program, wherein the method comprises the steps that: a client side obtains an SK corresponding to a program from a server side; the server side generates a CK at random in an encryption cycle to make the CK and the encryption cycle in one-to-one correspondence; the server side divides the program in each encryption cycle into a plurality of program units, encrypts the corresponding program unit by the CK in each encryption cycle, and aligns the generated encrypted program units into an encrypted program stream; the server side encrypts each CK into a CK ciphertext by the SK; the server side sends the encrypted program stream and a corresponding ECM to the user side, wherein the ECM includes a CK ciphertext which is in the same encryption cycle of the encrypted program stream; the user side decrypts the CK ciphertext by the SK to obtain a CK plaintext; the user side decrypts each encrypted program unit with the CK plaintext and gets the plaintext of corresponding program unit, and connects the plaintext of each program unit to form a program stream and plays the program stream. By utilizing the technical scheme of the invention, the security of program transmission is improved.