Method and apparatus for a non-revealing do-not-contact list system

A computer implemented method to identify email addresses registered on a do not contact list that are in a client's list without revealing the email addresses on the do not contact list or the client's list comprising:

• the client encrypting at least certain of entries on the client's list to create a plurality of encrypted entries, where each entry includes at least an email address, wherein the entries are encrypted in a way that it is intended that an intended recipient cannot decrypt the entries;
• the client transmitting over a network said plurality of encrypted entries from the client's list to a master do not contact list server without revealing the email address corresponding to each of the encrypted entries for comparison to encrypted entries of the do not contact list, wherein the master do not contact list server is configured to store the encrypted entries of the do not contact list, wherein the encrypted entries of the do not contact list were formed by encrypting information, including at least an email address;
• the client receiving results of the comparison, wherein the results of the comparison are an indication of which encrypted entries on the client's list match the encrypted entries on the do not contact list;
• the client determining which entries on the client's list matched based on said received results;
• the client removing the matched entries from the client's list and/or not transmitting email to the email addresses that correspond to the matched entries;
• and
• the client transmitting at least an email to the email addresses in the client's list that correspond to the encrypted entries on the client's list that did not match the encrypted entries on the do not contact list.

A computer implemented method to identify email addresses registered on a do-not-contact list that are in a client's list without revealing the email addresses on the do-not-contact list or the client's list comprising:

• the client encrypting at least certain of entries on the client's list to create a plurality of encrypted entries, where each entry includes at least an email address, wherein the entries are encrypted in a way that it is intended that an intended recipient cannot decrypt the entries;
• the client transmitting over a network said plurality of encrypted entries from the client's list to a master do not contact list server without revealing the email address corresponding to each of the encrypted entries for comparison to encrypted entries of the do-not-contact list, wherein the master do not contact list server is configured to store the encrypted entries of the do not contact list, wherein the encrypted entries of the do-not-contact list were formed by encrypting information, including at least an email address that belongs to a minor;
• the client receiving results of the comparison, wherein the results of the comparison are an indication of which encrypted entries on the client's list match the encrypted entries on the do not contact list;
• the client determining which entries on the client's list matched based on said received results;
• the client removing the matched entries from the client's list and/or not transmitting email to the email addresses that correspond to the matched entries;
• and
• the client transmitting at least an email to the email addresses in the client's list that correspond to the encrypted entries on the client's list that did not match the encrypted entries on the do not contact list.