Method and apparatus for verifying secure document timestamping

Abstract

According to one embodiment of the invention, a method is provided for receiving a timestamp from a caller via a telephone connection; receiving a device identifier from the caller, in which the device identifier identifies a device; determining a cryptographic key based on the device identifier; determining an indication of a time based on the timestamp and the cryptographic key; providing the indication of the time to the caller; determining an account; and charging a fee to the account.

1. A method, comprising:
 receiving, by a central controller, a timestamp from a caller via a telephone connection;  
 receiving, by a central controller, a device identifier from the caller, in which the device identifier identifies a device;  
 determining, by a central controller, a cryptographic key based on the device identifier;  
 determining, by a central controller, a representation of a time based on the timestamp and the cryptographic key;  
 providing, by a central controller, the representation of the time to the caller;  
 determining, by a central controller, an account; and  
 charging, by a central controller, a fee to the account.  
 
     
     
       2. The method of  claim 1 , in which the timestamp is optically detectable on a physical document. 
     
     
       3. The method of  claim 1 , in which receiving the timestamp comprises:
 receiving the timestamp at a central controller.  
 
     
     
       4. The method of  claim 1 , further comprising:
 receiving a telephone call from the caller.  
 
     
     
       5. The method of  claim 1 , in which receiving the timestamp comprises:
 receiving a sequence of DTMF signals; and  
 determining the timestamp based on the DTMF signals.  
 
     
     
       6. The method of  claim 5 , in which the sequence is entered by the caller at a keypad. 
     
     
       7. The method of  claim 1 , in which receiving the timestamp comprises:
 receiving a sequence of signals via an interactive response unit (IRU) in communication with the central controller.  
 
     
     
       8. The method of  claim 1 , in which receiving the timestamp comprises:
 receiving the timestamp via a toll-based telephone line.  
 
     
     
       9. The method of  claim 8 , in which the toll-based telephone line is associated with a 900 number. 
     
     
       10. The method of  claim 1 , in which the timestamp comprises a sequence of alphanumeric characters. 
     
     
       11. The method of  claim 1 , in which determining the account comprises:
 receiving an account identifier that identifies the account.  
 
     
     
       12. The method of  claim 1 , in which the timestamp comprises an account identifier that identifies the account: .  
     
     
       13. The method of  claim 1 , in which the account is associated with the caller. 
     
     
       14. The method of  claim 1 , in which the account is associated with a third party. 
     
     
       15. The method of  claim 1 , in which determining the account comprises:
 determining the account based on the device identifier.  
 
     
     
       16. The method of  claim 1 , in which the account is a prepaid account. 
     
     
       17. The method of  claim 1 , in which charging the fee comprises:
 debiting the account based on the fee.  
 
     
     
       18. The method of  claim 1 , in which determining the representation of the time comprises:
 performing a cryptographic operation on the timestamp.  
 
     
     
       19. The method of  claim 1 , in which determining the representation of the time comprises:
 decrypting the timestamp based on the cryptographic key.  
 
     
     
       20. The method of  claim 1 , in which providing the representation of the time comprises:
 transmitting the representation of the time to the caller.  
 
     
     
       21. The method of  claim 1 , in which providing the representation of the time comprises:
 displaying the representation of the time to the caller.  
 
     
     
       22. The method of  claim 1 , in which determining the cryptographic key comprises:
 selecting a database record based on the device identifier, in which the database record comprises the device identifier.  
 
     
     
       23. A method, comprising:
 receiving, by an interactive response unit ( IRU ), a sequence of DTMF signals from a caller via a telephone connection;  
 determining, by a central controller in communication with the IRU, a timestamp based on the DTMF signals;  
 receiving, by the IRU, a device identifier from the caller, in which the device identifier identifies a device;  
 determining, by the central controller, a cryptographic key based on the device identifier;  
 determining, by the central controller, a representation of a time based on the timestamp and the cryptographic key;  
 providing the representation of the time to the caller;  
 determining, by the central controller, an account; and  
 charging, by the central controller, a fee to the account.  
 
     
     
       24. A method, comprising:
 receiving, by a central controller, a timestamp from a timestamp recipient via an Internet connection;  
 receiving, by the central controller, a device identifier via the Internet connection, in which the device identifier identifies a device;  
 determining, by the central controller, a cryptographic key based on the device identifier;  
 determining, by the central controller, a representation of a time based on the timestamp and the cryptographic key;  
 providing, by the central controller, the representation of the time to the timestamp recipient via the Internet connection;  
 determining, by the central controller, an account; and  
 charging, by the central controller, a fee to the account.  
 
     
     
       25. A computer readable memory storing instructions operable to direct a processor to perform a method, the method comprising:
   receiving a timestamp from a caller via a telephone connection;        receiving a device identifier from the caller, in which the device identifier identifies a device;        determining a cryptographic key based on the device identifier;        determining a representation of a time based on the timestamp and the cryptographic key;        providing the representation of the time to the caller;        determining an account; and        charging a fee to the account.      
     
     
       26. An apparatus comprising:
   a processor; and        a storage device in communication with the processor, the storage device storing a program for directing the processor to perform a method, the method comprising:      receiving a timestamp from a caller via a telephone connection;        receiving a device identifier from the caller, in which the device identifier identifies a device;        determining a cryptographic key based on the device identifier;        determining a representation of a time based on the timestamp and the cryptographic key;        providing the representation of the time to the caller; determining an account; and        charging a fee to the account.        
     
     
       27. A method, comprising:
   receiving, by a central controller, a timestamp;        receiving, by the central controller, a device identifier, in which the device identifier identifies a device;        determining, by the central controller, a cryptographic key based on the device identifier;        determining, by the central controller, a time based on the timestamp and the cryptographic key;        transmitting, by the central controller, an indication of the time; and        charging, by the central controller, a fee to an account.      
     
     
       28. A computer readable memory storing instructions operable to direct a processor to perform a method, the method comprising:
   receiving a timestamp;        receiving a device identifier, in which the device identifier identifies a device;        determining a cryptographic key based on the device identifier;        determining a time based on the timestamp and the cryptographic key;        transmitting an indication of the time; and        charging a fee to an account.      
     
     
       29. An apparatus comprising:
   a processor; and        a storage device in communication with the processor, the storage device storing a program for directing the processor to perform a method, the method comprising:      receiving a timestamp;        receiving a device identifier, in which the device identifier identifies a device;        determining a cryptographic key based on the device identifier;        determining a time based on the timestamp and the cryptographic key;        transmitting an indication of the time; and        charging a fee to an account.