US Patent 11329831 Practical end-to-end cryptographic authentication for telephony over voice channels

Methods and apparatuses for providing cryptographic authentication within a voice channel are disclosed. The methods and apparatuses can provide cryptographic authentication solely within a voice channel or can use a combination of a voice channel and another data channel. A method for providing cryptographic authentication within a voice channel can operate between telephonic systems and be suitable for operating over G.711/PCMu, AMR and SPEEX™ codecs, and suitable for operating over mobile, PSTN, and VOIP networks. The method can include providing a modem that is codec agnostic and suitable for executing a TLS-based authentication protocol. The method can include using frequency-shift modulation within a frequency range of 300-3400 Hz.