Method and apparatus for authentication of recorded audio
AssigneeAdvanced Decisions Inc.
InventorsRoman Kresina, Michael Landino
Life of this patent
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Abstract
A set of procedures is described which permit signing digital audio recordings by means of private keys, and which permit later authentication of such recordings, for example in a courtroom, in a way that is well suited to comprehension by non-technical personnel. Importantly, the explanation leading to such comprehension does not enable the creation of tampered recordings that would appear to be authentic. The procedures call for signing by trusted and disinterested third parties and for distributing hardware tokens storing various keys and key pairs. The format of the digital audio recordings permits playback on conventional equipment and also on equipment having cryptographic capabilities for authentication.
Claims30
An authentication method comprising the steps of:
- making a digital audio recording of an event, yielding a first file;
- extracting a hash from the first file;
- cryptographically signing the hash using a first private key corresponding to a first public key, yielding a signature;
- cryptographically signing the first public key using a second private key corresponding to a second public key, yielding a certificate further comprising the first public key;
- communicating the first file, the signature, and the certificate to at least one person;
- communicating the second public key from a trusted source to the at least one person;
- providing to the at least one person an explanation of the extracting step, the first signing step, and the second signing step, and of the correspondence between the first private and public keys, and of the correspondence between the second private and public keys;
- authenticating the certificate by means of the second public key, the authenticating performed in the presence of the at least one person;
- authenticating the signature by means of the first public key from the certificate, the authenticating performed in the presence of the at least one person;
- and
- playing the audio recording in the presence of the at least one person.
Audio file archival apparatus for use with an audio event of interest, the apparatus comprising:
- an analog-to-digital converter responsive to the audio event for creating a first digital file indicative of the audio event;
- means responsive to the first digital file for extracting a first hash therefrom;
- secure means containing a first private key, responsive to the first hash for generating a signature;
- and
- means communicating the first digital file and the signature external to the apparatus.
Audio file authentication apparatus for use with a first digital file indicative of an audio event, and with a signature, and with a first public key, the apparatus comprising:
- means authenticating the first public key;
- means responsive to the first data file for extracting a second hash therefrom;
- means responsive to the signature and the first public key for generating an output;
- means comparing the output with the second hash;
- means responsive to a successful comparison for annunciating the successful comparison;
- and
- means responsive to the first digital file for playing back the audio event.
An audio file archival and authentication apparatus for use with an audio event of interest, the archival apparatus comprising:
- an analog-to-digital converter responsive to the audio event for creating a first digital file indicative of the audio event;
- means responsive to the first digital file for extracting a first hash therefrom;
- secure means containing a first private key, responsive to the first hash for generating a signature;
- and
- communicating the first digital file and the signature to the authentication apparatus;
- the authentication apparatus comprising:
- means authenticating a first public key corresponding to the first private key;
- means responsive to the first data file for extracting a second hash therefrom;
- means responsive to the signature and the first public key for generating an output;
- means comparing the output with the second hash;
- means responsive to a successful comparison for annunciating the successful comparison;
- and
- means responsive to the first digital file for playing back the audio event.
A digital audio file comprising first, second, and third portions, the first portion comprising format information, the second portion comprising audio data and means indicating the location of the end of the audio data, the third portion comprising a cryptographic signature of at least the audio data.
A method for use with a digital audio file comprising first and second portions, the first portion comprising format information, the second portion comprising audio data and means indicating the location of the end of the audio data, the method comprising the steps of:
- calculating a first hash based at least on the audio data;
- cryptographically signing the first hash, yielding a signature;
- and
- adding a third portion to the file comprising the signature.
A digital audio file having a length and a format, the file comprising:
- four bytes spelling the word “RIFF” in ASCII;
- four bytes defining a first number;
- a number of bytes indicative of the format of the file;
- four bytes spelling the word “data” in ASCII;
- four bytes defining a second number, the second number indicative of a number of audio data bytes;
- the first number of audio data bytes;
- a cryptographic signature calculated with respect to at least the first number of data bytes;
- the first number selected to be indicative of the length of the file less eight bytes.
A computer-readable storage medium comprising an digital audio file having a length and a format, the file comprising:
- four bytes spelling the word “RIFF” in ASCII;
- four bytes defining a first number;
- a number of bytes indicative of the format of the file;
- four bytes spelling the word “data” in ASCII;
- four bytes defining a second number, the second number indicative of a number of audio data bytes;
- first number of audio data bytes;
- a cryptographic signature calculated with respect to at least the first number of data bytes;
- the first number selected to be indicative of the length of the file less eight bytes
Dependencies are inferred from the claim text.