Method and system for detecting when an outgoing communication contains certain content

A method in a computer system having a memory and a processor for identifying whether an outgoing communication contains target information, the method comprising:

• providing documents that contain target information;
• for each of at least some words in the provided documents,
• with the processor, determining an importance value for the word,
• in response to determining that the importance value determined for the word exceeds a threshold, designating the word as a keyword, and
• in response to determining that the importance value determined for the word does not exceed the threshold, not designating the word as a keyword;
• generating a sentence hash table that, for each of at least some sentences, maps a hash code derived from the sentence to documents that contain the sentence;
• receiving an outgoing communication;
• using the sentence hash table to locate documents of the provided documents that contain one or more sentences that match one or more sentences of the received outgoing communication;
• and
• with the processor, comparing the received outgoing communication to at least a portion of the located documents to determine whether the received outgoing communication contains target information.

A method in a computer system having a memory and a processor for identifying whether an outgoing communication contains target information, the method comprising:

• providing documents that contain target information;
• for each of at least some words in the provided documents,
• with the processor, determining an importance value for the word,
• in response to determining that the importance value determined for the word exceeds a threshold, designating the word as a keyword, and
• in response to determining that the importance value determined for the word does not exceed the threshold, not designating the word as a keyword;
• generating a keyword index that, for each of at least some keywords, maps the keyword to sentences of the provided documents that contain the keyword;
• receiving an outgoing communication;
• using the keyword index to locate documents of the provided documents that contain one or more sentences containing at least one keyword of the received outgoing communication;
• and
• with the processor, comparing the received outgoing communication to at least a portion of the located documents to determine whether the received outgoing communication contains target information.

A computer-readable storage device containing instructions for controlling a computer system to identify whether a first document contains content similar to content of target documents, by operations comprising:

• for each of at least some words of the target documents,
• with a processor, determining an importance value for the word,
• comparing the determined importance value to a threshold, and
• when the determined importance value exceeds the threshold, designating the word as a keyword;
• creating a keyword index that, for each of at least some keywords of the target documents, maps the keyword to one or more target documents that contain the keyword;
• identifying keywords of the first document;
• using the created keyword index to locate candidate documents, from among the target documents, based on a similarity between keywords of the target documents and the identified keywords of the first document;
• and
• comparing the located candidate documents to the first document to determine whether the first document contains content similar to at least one candidate document.

A computer-readable storage device containing instructions for controlling a computer system to identify whether a first document contains content similar to content of target documents, by operations comprising:

• for each of at least some words of the target documents,
• with a processor, determining an importance value for the word,
• comparing the determined importance value to a threshold, and
• when the determined importance value exceeds the threshold,
• designating the word as a keyword;
• generating a sentence hash table that, for each of at least some sentences of the target documents, maps a hash code derived from the sentence to target documents that contain the sentence;
• using the sentence hash table to locate candidate documents that contain sentences that match sentences of the first document;
• and
• comparing the located candidate documents to the first document to determine whether the first document contains content similar to at least one candidate document,
• wherein the sentence hash table is generated prior to identifying sentences of the first document.

A computer system having a memory and a processor for determining whether a first electronic mail message contains target information, comprising:

• a document store containing target electronic mail messages that contain target information;
• a component configured to, for each of at least some words in the target electronic mail messages,
• determine an importance value for the word, and
• when the importance value determined for the word exceeds a first threshold, designate the word as a keyword,
• a component configured to, for each of at least some of the target electronic mail messages,
• calculate a similarity value for the target electronic mail message based at least in part on common keywords between the target electronic mail message and the first electronic mail message,
• compare the calculated similarity value to a second threshold, and
• designate the target electronic mail message as a candidate electronic mail message if the comparison indicates that the calculated similarity value is greater than the second threshold;
• and
• a component configured to compare the first electronic mail message to the designated candidate electronic messages to determine whether the first electronic mail message contains target information,
• wherein the determination of whether the first electronic mail message contains target information is based at least in part on the designated keywords, and
• wherein at least one of the components comprises computer-executable instructions stored in memory for execution by the processor.

A computer-readable storage device containing instructions for controlling a computer system to identify whether a first document contains content similar to content of target documents, by operations comprising:

• for each of at least some words of the target documents,
• with a processor, determining an importance value for the word,
• comparing the determined importance value to a threshold, and
• when the determined importance value exceeds the threshold,
• designating the word as a keyword;
• selecting from the target documents candidate documents based on a similarity between keywords of the target documents and keywords of the first document;
• and
• comparing the candidate documents to the first document to determine whether the first document contains content similar to a candidate document at least in part by, for each candidate document,
• determining a number of exact matches between sentences of the first document and sentences of the candidate document, and
• in response to determining that the number of exact matches between sentences of the first document and sentences of the candidate document does not exceed an exact match threshold,
• determining a number of fuzzy matches between sentences of the first document and sentences of the candidate document.