Abstract: A random number generation method and apparatus using a low-power microprocessor is provided. In the random number generation method, a low-power microprocessor determines whether external power is supplied to a random number generator. The low-power microprocessor updates an internal state of the random number generator based on a first scheme if it is determined that the external power is supplied to the random number generator. The low-power microprocessor updates the internal state of the random number generator based on a second scheme different from the first scheme if it is determined that the external power is not supplied to the random number generator.

Abstract: A method of generating a random number using nonvolatile memory and an apparatus for the same are provided. The method of generating a random number includes reading random number state information from nonvolatile memory when power is supplied; updating the random number state of a random number generator using the random number state information and a saving entropy source, thereby producing updated random number state information; storing the updated random number state information in the nonvolatile memory; updating a random number state of the random number generator using the updated random number state information and a generating entropy source, thereby producing a generating random number state information; and producing a random number to be used in an application program using the generating random number state information and the generating entropy source.

Abstract: A cipher communication method for an encryption apparatus an includes: receiving a second encryption key while performing a cipher communication using a first encryption key; storing encryption key input information on the first and second encryption keys in a static region; copying the stored encryption key input information into a dynamic region; selecting any one of the first and second encryption keys based on the copied encryption key input information and current time information; generating encryption key position information and encryption key selection information on the selected encryption key; and transmitting a cipher text and the encryption key selection information to another encryption apparatus connected to the encryption apparatus through a network such that the another encryption apparatus acquires an encryption key to decrypt the cipher text.

Abstract: A random number generation apparatus and method using input time information is provided. The random number generation apparatus using input time information includes an information obtainment unit for obtaining input time information from input means. An initial value calculation unit calculates an initial value for random number generation using the input time information. A random number generation unit generates a random number using the initial value for random number generation.

Abstract: A random number generation method and apparatus using a low-power microprocessor is provided. In the random number generation method, a low-power microprocessor determines whether external power is supplied to a random number generator. The low-power microprocessor updates an internal state of the random number generator based on a first scheme if it is determined that the external power is supplied to the random number generator. The low-power microprocessor updates the internal state of the random number generator based on a second scheme different from the first scheme if it is determined that the external power is not supplied to the random number generator.

Abstract: A cipher communication method for an encryption apparatus an includes: receiving a second encryption key while performing a cipher communication using a first encryption key; storing encryption key input information on the first and second encryption keys in a static region; copying the stored encryption key input information into a dynamic region; selecting any one of the first and second encryption keys based on the copied encryption key input information and current time information; generating encryption key position information and encryption key selection information on the selected encryption key; and transmitting a cipher text and the encryption key selection information to another encryption apparatus connected to the encryption apparatus through a network such that the another encryption apparatus acquires an encryption key to decrypt the cipher text.

Abstract: A method of generating a random number using nonvolatile memory and an apparatus for the same are provided. The method of generating a random number includes reading random number state information from nonvolatile memory when power is supplied; updating the random number state of a random number generator using the random number state information and a saving entropy source, thereby producing updated random number state information; storing the updated random number state information in the nonvolatile memory; updating a random number state of the random number generator using the updated random number state information and a generating entropy source, thereby producing a generating random number state information; and producing a random number to be used in an application program using the generating random number state information and the generating entropy source.

Abstract: Provided are an apparatus and method for estimating a voice data value corresponding to a silent period produced in a key resynchronization process using the sine waveform characteristic of voice when encrypted digital voice data is transmitted in one-way wireless communication environment. The apparatus includes a transmitter that generates a key resynchronization frame containing key resynchronization information and vector information on voice data inserted thereinto and transmits the key resynchronization frame, and a receiver that receives the key resynchronization frame from the transmitter, extracts the vector information inserted in the key resynchronization frame, and estimates a voice data value corresponding to the key resynchronization period. Based on change ratio between slopes calculated using received voice data, it is possible to estimate the voice data corresponding to a silent period, which improves communication quality.

Abstract: Disclosed are a method of inserting vector information for estimating voice data in a key re-synchronization period, a method of transmitting vector information, and a method of estimating voice data in a key re-synchronization period using vector information, capable of estimating the voice data that corresponds to a silent period occurring in a key re-synchronization process when an encrypted digital voice is transmitted in a unidirectional wireless communication environment. A transmitter side inserts accumulation information (i.e., vector information) of a voice change direction of the transmitted previous frame in a key re-synchronization frame, using a voice feature that draws a sine wave, when making the key re-synchronization frame for the re-synchronization, and transmits the key re-synchronization frame with the vector information inserted thereto. A receiver side estimates the voice data value in the key re-synchronization period using the accumulation information (i.e.