Secure teleconferencing

A method of obtaining a secure teleconference between three or more conferees, comprising the steps of:

• decrypting at least three encrypted information streams from the three or more conferees;
• re-encrypting the decrypted information streams;
• and
• combining the re-encrypted information streams in a conference bridge co-located with circuits performing the decrypting and re-encrypting steps.

A secure teleconferencing apparatus, comprising:

• a conference bridge;
• a gating circuit for directing only one of a plurality of encrypted information streams to the conference bridge at a time;
• and
• a generator of encrypted silence directed to the conference bridge when all of the plurality of encrypted information streams represent silence.

A public switched telephone network, comprising:

• at least one central office switching system capable of being configured as a teleconference bridge;
• at least first, second, and third decryption/re-encryption units co-located with the central office switching system for receiving at least first, second, and third information streams from at least first, second, and third conferees, the information streams received from the conferees being encrypted in accordance with respective conferee encryption algorithms;
• the at least first, second, and third decryption/re-encryption units each comprising a means for decrypting the information streams received from the conferees in accordance with respective conferee encryption algorithms and a means for re-encrypting the decrypted information streams in accordance with a single conference encryption algorithm;
• a means for gating the re-encrypted information streams to inputs of a conference bridge formed in the switching system, the conference bridge producing a combined conference output and directing that conference output back to the conferees.