Program protection device

1. A method for protecting a program, the method comprising:

calling a protection domain connection unit including a decryption unit that decrypts an encrypted protection domain of a protection domain unit;

generating with the decryption unit a running code by decrypting the encrypted protection domain of the protection domain unit among binary codes of a program and determining whether to store the encrypted protection domain in a protection domain storage unit;

running the generated running code;

verifying integrity of the running code; and

removing the running code to return to the encrypted protection domain when the running of the running code is terminated;

wherein the determining whether to store the encrypted protection domain in a protection domain storage unit comprises:

when a plurality of encrypted protection domains exist,

selecting whether to store the encrypted protection domain in a protection domain storage unit or to encrypt the running code after generating the running code corresponding to the encrypted protection domain without storing the encrypted protection domain in the protection domain storage unit, based on respective calling frequencies of the encrypted protection domains.

2. The method of claim 1 , wherein the removing the running code to returning to the encrypted protection domain comprises copying the encrypted protection domain stored in a separate place when the encrypted protection domain is stored in the separate place or encrypting the running code.

3. The method of claim 1 , wherein the protection domain unit includes a start point display unit to display a start point of the encrypted protection domain, and an end point display unit to display an end point of the encrypted protection domain; and

wherein the start point display unit and the end point display unit comprise:

a label to acquire an address of each point when the program is run; and

a marking code to search a start point and an end point of a protection domain to be encrypted without an influence upon the running of the program.

4. The method of claim 3 , wherein the encrypted protection domain is acquired by encrypting binary codes from a marking code included in the start point display unit to a marking code included in the end point display unit after binary codes of the program are generated.

5. The method of claim 1 , wherein the verifying the integrity of the running code extracts a hash code by inputting the running code unit into a hash function, determines whether the extracted hash code corresponds to one of stored hash codes, and stops the running of the program when the extracted hash code differs from the stored hash code.