An information encryption system and an information encryption method for encrypting character information and decrypting the encrypted information by using optical character recognition includes a user terminal comprising: a viewer region display unit for displaying a viewer region at the very top of a screen; a viewer character recognition unit for recognizing in real-time characters displayed on a screen region covered by the viewer region, a viewer character encryption unit for generating an encrypted character by encrypting a first character to be encrypted by using a cipher when the first character is recognized; an encrypted character substitution unit for deleting the first character and substitutively inputting the encrypted character; and a viewer character display unit for displaying a non-encrypted second character as it is, and decrypting an encrypted second character by using a cipher and displaying the same in an original character when the second character to be displayed is recognized.