Verification data encoding method, original image verification method and apparatus, and computer readable medium

An original image verification method for determining whether an alteration to an original digital image is effected based on a result of decoding of an input digital image, the input digital image containing a plurality of pixels, comprising the steps of:

• inputting a key information;
• providing a pseudo-random code by taking the pseudo-random code from a sequence of pseudo-random codes initialized by the key information;
• calculating a verification data through a predetermined operation based on a pixel value indicated by a predetermined number of bits of the pixel of concern in the input digital image and based on the pseudo-random code;
• and
• determining whether a value of the verification data matches with a value of the pixel of concern in the input digital image, in order to determine whether an alteration to the original digital image is effected, based on a result of the determination.

An original image verification apparatus for determining whether an alteration to an original image is effected based on a decoding result, comprising:

• a key input unit for inputting a key information;
• a pseudo-random code generator for providing a pseudo-random code by taking one of pseudo-random codes in a sequence initialized by the key information;
• a verification data calculation unit for calculating a verification data through a predetermined operation based on a pixel value indicated by a predetermined number of bits of the pixel of concern in the input digital image and based on the pseudo-random code;
• and
• a determination unit for determining whether a value of the verification data matches with a value of the pixel of concern in the input digital image, in order to determine whether an alteration to the original digital image is effected, based on a result of the determination.

A computer readable medium storing a program of code instructions executable by a computer to perform an original image verification method to determine whether an alteration to an original image is effected, based on a result of decoding of an encoded image, the original image verification method comprising the steps of:

• inputting a key information;
• providing a pseudo-random code by taking the pseudo-random code from a sequence of pseudo-random codes initialized by the key information;
• calculating a verification data through a predetermined operation based on a pixel value indicated by a predetermined number of bits of the pixel of concern in the input digital image and based on the pseudo-random code;
• and
• determining whether a value of the verification data matches with a value of the pixel of concern in the input digital image, in order to determine whether an alteration to the original digital image is effected, based on a result of the determination.