| CPC G06F 18/22 (2023.01) [G06F 16/367 (2019.01); G06F 16/951 (2019.01); G06F 40/205 (2020.01)] | 9 Claims |
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1. A notification service server capable of providing an access notification service to harmful sites, comprising a processor configured to:
hold a word database storing a plurality of predetermined different words;
hold a harmful word database storing a plurality of harmful words pre-selected among the plurality of words;
when receiving access address information of a first site and terminal unique identification information of a client terminal from router equipment as a client terminal currently connected to predetermined router equipment accesses the first site, access the first site based on the access address information of the first site, and then crawl a text posted on the accessed first site;
when the text posted on the first site is crawled, search words matching the plurality of words in the crawled text with reference to the word database;
when a plurality of first words are searched as the words matching the plurality of words in the crawled text, cluster the plurality of first words into k (k is a natural number of 3 or more) word groups based on a semantic similarity between the plurality of first words;
verify whether there is a word group of which semantic similarity with the plurality of harmful words exceeds a predetermined reference similarity among k word groups; and
when it is verified that there is at least one word group as the word group of which semantic similarity with the plurality of harmful words exceeds a reference similarity among k word groups, determine that a situation in which the client terminal attempts to access the harmful site occurs, and then transmit a warning message for notifying that the client terminal attempts to access the harmful site while transmitting the terminal unique identification information of the client terminal to a predetermined manager terminal,
wherein the processor is further configured to:
hold an authentication number storage unit storing an authentication number of t (t is a natural number of 2 or more) digits, which is pre-shared with the manager terminal,
hold a hash function storage unit storing a predetermined hash function pre-shared with the manager terminal;
store and hold a serial number table in which serial numbers of different t digits are recorded, which correspond to a plurality of predetermined time zones, respectively, which are pre-shared with the manager terminal;
generate an encryption event for encrypting and transmitting the terminal unique identification information of the client terminal when it is determined that the situation in which the client terminal attempts to access the harmful site occurs;
extract, when the encryption event is generated, a first serial number corresponding to a first time zone to which a time point when the encryption event is generated belongs from the serial number table;
constitute, when the first serial number is extracted, a result value when performing a modulo-2 operation for each of t numbers constituting the authentication number by bitstreams to generate a first operation code of t bits and constituting a result value when performing the modulo-2 operation for each of t numbers constituting the first serial number by the bitstreams to generate a second operation code of t bits;
perform an XOR operation between the first operation code and the second operation code to generate a t-bit seed code, and then applying the seed code to the hash function as an input to generate a first hash value;
when the first hash value is generated, encrypt the terminal unique identification information of the client terminal with the first hash value to generate first encryption information; and
when the first encryption information is generated, transmit the warning message to the manager terminal while transmitting the first encryption information,
wherein the manager terminal pre-stores the authentication number, the hash function, and the serial number table on a memory, extracts the first serial number corresponding to the first time zone to which a time point of receiving the first encryption information and the warning message belongs from the serial number table when receiving the first encryption information and the warning message from the notification service server, and then constitutes a result value when performing the modulo-2 operation for each of t numbers constituting the authentication number by the bitstreams to generate the first operation code of t bits and constitutes a result value when performing the modulo-2 operation for each of t numbers constituting the first serial number by the bitstreams to generate the second operation code of t bits, and then performs the XOR operation between the first operation code and the second operation code to generate the seed code of t bits, applies the seed code to the hash function as the input to generate the first hash value, and then decodes the first encryption information with the first hash value to restore the terminal unique identification information of the client terminal and display the warning message on a screen jointly with the terminal unique identification information of the client terminal.
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