11. A system for searching unstructured documents for structured data, the system comprising: a receiving module, stored in memory, that receives a request to search unstructured documents for a document that contains: a value from a first field of a dataset; and a value from a second field of the dataset; an index-generating module, stored in memory, that generates a secure search index for searching the unstructured documents by, for each record in the dataset: identifying, within the dataset, the record's value from the first field and the record's value from the second field; generating a first hashed key from the record's value from the first field and the record's value from the second field; adding the first hashed key to the secure search index; an extracting module, stored in memory, that extracts a first token and a second token from an unstructured document; a key-generating module, stored in memory, that generates a second hashed key from the first token and the second token; a querying module, stored in memory, that queries the secure search index to determine whether the second hashed key is contained in the secure search index; a responding module, stored in memory, that responds, upon determining that the second hashed key is contained in the secure search index, to the request with information about the unstructured document; at least one physical processor configured to execute the receiving module, the index-generating module, the extracting module, the key-generating module, the querying module, and the responding module.
11. A system for searching unstructured documents for structured data, the system comprising: a receiving module, stored in memory, that receives a request to search unstructured documents for a document that contains: a value from a first field of a dataset; and a value from a second field of the dataset; an index-generating module, stored in memory, that generates a secure search index for searching the unstructured documents by, for each record in the dataset: identifying, within the dataset, the record's value from the first field and the record's value from the second field; generating a first hashed key from the record's value from the first field and the record's value from the second field; adding the first hashed key to the secure search index; an extracting module, stored in memory, that extracts a first token and a second token from an unstructured document; a key-generating module, stored in memory, that generates a second hashed key from the first token and the second token; a querying module, stored in memory, that queries the secure search index to determine whether the second hashed key is contained in the secure search index; a responding module, stored in memory, that responds, upon determining that the second hashed key is contained in the secure search index, to the request with information about the unstructured document; at least one physical processor configured to execute the receiving module, the index-generating module, the extracting module, the key-generating module, the querying module, and the responding module. 14. The system of claim 11 , wherein: the receiving module receives the request to search unstructured documents for the document comprises receiving a request to search unstructured documents for a document that contains: the value from the first field of the dataset; the value from the second field of the dataset; and a value from a third field of the dataset, wherein: values from the first field follow a first known pattern; values from the third field follow a second known pattern; values from the second field do not follow a known pattern; the index-generating module further generates an additional secure search index by, for each record in the dataset: identifying, within the dataset, the record's value from the second field and the record's value from the third field; generating a third hashed key from the record's value from the second field and the record's value from the third field; adding the third hashed key to the additional secure search index; the extracting module further extracts a third token from the unstructured document; the key-generating module further generates a fourth hashed key from the second token and the third token; the querying module further queries the additional secure search index to determine whether the fourth hashed key is contained in the additional secure search index; the responding module responds to the request with information about the unstructured document upon determining that the fourth hashed key is contained in the additional secure search index.