Abstract: A computer system module(s) substitutes a double scalar multiplication, used for signature verification in an encryption/decryption system, for two single scalar multiplications. The modules verify a group equation defined by [S]B=R+[k]A? of the encryption/decryption system, where S is an integer characterized by the signature, K is an integer generated by a message being encrypted, B is a base point on the elliptic curve, R is a point on the elliptic curve and characterized by the signature, and A? is a public key. The modules optionally rearrange the group equation to [S]B+[?k]A?=R, and convert it to [S]B+[n?k]A?=R, where n is the order of the base point. The modules determine a joint sparse form for the integers S and n?k and apply the Shamir's algorithm to the joint sparse form to verify the group equation.

Abstract: A method for ciphering protected content communicated between a first device and a plurality of devices over a plurality of channels comprises performing authentication between the first device and each of the plurality of devices to create two or more shared key and initialization vector pairs allowing the ciphering of the protected content; generating a key stream for each of the channels based on a selected one of the two or more of shared key and initialization vector pairs; maintaining a buffer for each channel, each of the buffer containing the key stream generated for the corresponding channel; and ciphering data incoming on a selected channel using the selected key stream from the buffer corresponding to the selected channel.

Abstract: A method of improving the efficiency of an encryption/decryption process implementing the NIST FIPS 197 standard which includes a substitution box (S-box) and an inverse substitution (inverse S-box), comprises concatenating the S-box and inverse S-box to form a combined lookup table, and folding the concatenated table to generate a folded lookup table. The folded lookup table may be indexed for an encryption operation and for a decryption operation using a signal indicative of whether encryption or decryption is used.

Abstract: A secure generic encryption system for nonsecure datapaths comprises a format-specific adaptation layer/data path for receiving and processing nonsecure content data; an authentication engine located within a security perimeter and coupled to an external communication interface for authentication and supplying the format-specific adaptation layer/data path, located outside the security perimeter, with an output signal indicating whether authentication is successful; and a generic encryption module located within the security perimeter and coupled (1) to the authentication engine for receiving from the authentication engine initialization vectors, encryption keys, and the output signal indicating whether authentication is successful, and (2) to the format-specific adaptation layer/data path for (a) receiving a read signal from the format-specific adaptation layer/data path, and (b) providing the format-specific adaptation layer/data path with a data-available signal to indicate whether data is available to be

Abstract: A method for determining the color depths of the video data for a selected frame in High-bandwidth Digital Content Protection (HDCP) video data transmitted over a High Definition Multimedia Interface (HDMI), in which (a) the beginning of the selected frame is marked with a vertical synchronization (VSYNC) signal and (b) a mark in a window of opportunity (WOO) for the selected frame indicates whether or not that frame is encrypted. The method detects, for the selected frame, the length of the interval between a VSYNC signal and the location of at least one of (i) the start of the corresponding WOO and (ii) the mark indicating whether or not the selected frame is encrypted, and then determines the color depth of the video data for the selected frame based on the detected length.

Abstract: An embodiment of a method and apparatus for ciphering data. Data is provided for ciphering. The data is ciphered in a plurality of steps. For each step, determining an encoding for error detection of the data being processed within the step. Determining an output error detection encoding for the step. Processing data of the round to provide output error detection encoding. Then, verifying the encoding against a determined output error detection encoding. If the output error detection encoding is not the same as the determined error detection encoding, providing a signal indicating the presence of an error within the cipher process.

Abstract: An HDCP receiver device that receives frames from an HDCP transmitter device. The receiver device has a frame counter that is updated for each frame that is received from the transmitter device and that includes encrypted content, while the receiver device is in a pre-authorization mode. During the pre-authorization mode, the receiver device does not decrypt any received frame bearing encrypted content. While the receiver device waits to transition from the pre-authorization mode to a post-authorization mode in which the receiver device can begin to decrypt any received frames that include encrypted content, the frame counter is updated for each frame received that includes encrypted content. In the post-authorization mode, the frame counter has a nonzero value if frames including encrypted content were received by the receiver device during the pre-authorization mode.

Abstract: A method of improving the efficiency of an encryption/decryption process implementing the NIST FIPS 197 standard which includes a substitution box (S-box) and an inverse substitution (inverse S-box), comprises concatenating the S-box and inverse S-box to form a combined lookup table, and folding the concatenated table to generate a folded lookup table. The folded lookup table may be indexed for an encryption operation and for a decryption operation using a signal indicative of whether encryption or decryption is used.

Abstract: An embodiment of a method and apparatus for ciphering data. Data is provided for ciphering. The data is ciphered in a plurality of steps. For each step, determining an encoding for error detection of the data being processed within the step. Determining an output error detection encoding for the step. Processing data of the round to provide output error detection encoding. Then, verifying the encoding against a determined output error detection encoding. If the output error detection encoding is not the same as the determined error detection encoding, providing a signal indicating the presence of an error within the cipher process.

Abstract: A method for ciphering protected content communicated between a first device and a plurality of devices over a plurality of channels comprises performing authentication between the first device and each of the plurality of devices to create two or more shared key and initialization vector pairs allowing the ciphering of the protected content; generating a key stream for each of the channels based on a selected one of the two or more of shared key and initialization vector pairs; maintaining a buffer for each channel, each of the buffer containing the key stream generated for the corresponding channel; and ciphering data incoming on a selected channel using the selected key stream from the buffer corresponding to the selected channel.

Abstract: What is disclosed is an embodiment of a method for ciphering data. Data is provided for ciphering thereof. The data is ciphered in a plurality of steps. For each step, an encoding for error detection of the data for being processed within the step is determined. An output error detection encoding for the step is determined. The data for being processed within the round is processed to provide output error detection encoding which is then verified against the determined output error detection encoding. When the output error detection encoding is other than same as the determined error detection encoding, providing a signal indicative of an error within the cipher process.

Abstract: A secure generic encryption system for nonsecure datapaths comprises a format-specific adaptation layer/data path for receiving and processing nonsecure content data; an authentication engine located within a security perimeter and coupled to an external communication interface for authentication and supplying the format-specific adaptation layer/data path, located outside the security perimeter, with an output signal indicating whether authentication is successful; and a generic encryption module located within the security perimeter and coupled (1) to the authentication engine for receiving from the authentication engine initialization vectors, encryption keys, and the output signal indicating whether authentication is successful, and (2) to the format-specific adaptation layer/data path for (a) receiving a read signal from the format-specific adaptation layer/data path, and (b) providing the format-specific adaptation layer/data path with a data-available signal to indicate whether data is available to be

Abstract: A method for performing a cryptographic function on text to generate converted text comprises producing a random key stream having a first block size in a first frequency domain; converting the random key stream having a first block size in the first frequency domain to a random key stream in a second frequency domain; converting the random key stream having the first block size in the second frequency domain into smaller block sizes, thereby producing smaller block-sized random key stream of the second frequency domain; and converting the text using the smaller block-sized random key stream of the second frequency domain to produce the converted text. The frequency in the first frequency domain is preferably lower than the frequency in the second frequency domain.

Abstract: A method for performing a cryptographic function on text to generate converted text comprises producing a random key stream having a first block size in a first frequency domain; converting the random key stream having a first block size in the first frequency domain to a random key stream in a second frequency domain; converting the random key stream having the first block size in the second frequency domain into smaller block sizes, thereby producing smaller block-sized random key stream of the second frequency domain; and converting the text using the smaller block-sized random key stream of the second frequency domain to produce the converted text. The frequency in the first frequency domain is preferably lower than the frequency in the second frequency domain.

Abstract: An HDCP receiver device that receives frames from an HDCP transmitter device. The receiver device has a frame counter that is updated for each frame that is received from the transmitter device and that includes encrypted content, while the receiver device is in a pre-authorization mode. During the pre-authorization mode, the receiver device does not decrypt any received frame bearing encrypted content. While the receiver device waits to transition from the pre-authorization mode to a post-authorization mode in which the receiver device can begin to decrypt any received frames that include encrypted content, the frame counter is updated for each frame received that includes encrypted content. In the post-authorization mode, the frame counter has a nonzero value if frames including encrypted content were received by the receiver device during the pre-authorization mode.

Abstract: A method for determining the color depths of the video data for a selected frame in High-bandwidth Digital Content Protection (HDCP) video data transmitted over a High Definition Multimedia Interface (HDMI), in which (a) the beginning of the selected frame is marked with a vertical synchronization (VSYNC) signal and (b) a mark in a window of opportunity (WOO) for the selected frame indicates whether or not that frame is encrypted. The method detects, for the selected frame, the length of the interval between a VSYNC signal and the location of at least one of (i) the start of the corresponding WOO and (ii) the mark indicating whether or not the selected frame is encrypted, and then determines the color depth of the video data for the selected frame based on the detected length.

Abstract: What is disclosed is an embodiment of a method for ciphering data. Data is provided for ciphering thereof. The data is ciphered in a plurality of steps. For each step, an encoding for error detection of the data for being processed within the step is determined. An output error detection encoding for the step is determined. The data for being processed within the round is processed to provide output error detection encoding which is then verified against the determined output error detection encoding. When the output error detection encoding is other than same as the determined error detection encoding, providing a signal indicative of an error within the cipher process.

Abstract: A system for generating random key stream cipher texts passes an unencrypted random key stream through an AES engine to produce encrypted cipher text having a first block size in a first frequency domain; converts the encrypted cipher text in the first frequency domain to encrypted cipher text in a second frequency domain; and converts the encrypted cipher text having the first block size in the second frequency domain into smaller block sizes. The frequency in the first frequency domain is preferably lower than the frequency in the second frequency domain. The converting of the encrypted cipher text in the first frequency domain to encrypted cipher text in a second frequency domain may be effected by a dual clock domain FIFO.

Abstract: Methods and apparatus for multiplying integers using a double-base numbering system are presented. In one embodiment, a method includes splitting a first integer into a plurality of binary blocks. The method may also include encoding the plurality of binary blocks into a plurality of encoded blocks in a double-base numbering system. Additionally, the method may include producing a plurality of multiples of a second integer. The method may also include producing a plurality partial results. The method may include selectively shifting the plurality of partial results to generate a plurality of shifted partial results, and adding the plurality of partial results and the shifted partial results to create the product of a plurality of integers.