摘要:
A program obfuscating device for generating obfuscated program from which unauthorized analyzer cannot obtain confidential information easily. The program obfuscating device stores original program that contains authorized program instructions and confidential process instruction group containing confidential information that needs to be kept confidential, generates process instructions which, when executed in predetermined order, provide same result, with execution of last process instruction thereof, as the confidential process instruction group, inserts the process instructions into the original program at position between start of the original program and the confidential process instruction group so as to be executed in the predetermined order, in place of the confidential process instruction group, generates dummy block as dummy of the process instructions, and inserts the dummy block and control instruction, which causes the dummy block to be bypassed, into the original program, and inserts branch instruction into the dummy block.
摘要:
Processing load on an executing device for conducting playback is high during the playback of contents since the executing device performs verification of the contents validity in parallel with the contents playback, and therefore the executing device has to be equipped with a highly efficient processor. The present invention reduces the processing load involved in the verification by using, for the verification, only a predetermined number of encrypted units selected randomly from multiple encrypted units constituting encrypted contents recorded on the DVD. In addition, the present invention is capable of improving the accuracy of detecting unauthorized contents to some extent by randomly selecting a predetermined number of encrypted units every time the verification is performed.
摘要:
A signature generation apparatus capable of preventing transcript attack on signature data is provided. The signature generation apparatus performing a digital signature operation with the use of a signature key: stores the signature key; performs the digital signature operation on signature target data with the use of the signature key to generate signature data; counts the cumulative count of digital signature operations having been performed by the signature generation unit with the use of the signature key; judges whether the cumulative count has reached a predetermined count; and inhibits the use of the signature key in the digital signature operation from then onward in a case where the judgment unit determines that the cumulative count has reached the predetermined count.
摘要:
A signature generation apparatus and a signature verification apparatus preventing an occurrence of an inappropriate signature verification error. The signature generation apparatus (110) including a signature generation unit (114) calculating signature vector (s, t) for a message m using a private key, and generating signature data S indicating polynomials sl and sh specifying the polynomial s and a polynomial th which is a quotient when the polynomial t is divided by q.
摘要:
A program converter (1) converts a program (P) which performs arithmetic addition processing to execute encryption, into a converted program (tP) which performs processing equivalent to the processing of the program (P). The program converter (1) includes: a key data extraction unit (10) which extracts key data from the program (P); an addition table generation unit (11) which generates an addition table from the extracted key data; a conversion table extraction unit (12) which extracts a conversion table from the program (P); a table merger unit (13) which generates a merger table by merging the generated-addition table and the extracted conversion table; a random number generation unit (14) which generates a random number; a table randomization unit (15) which generates a randomized merger table by randomizing the merger table using the generated random number; and a converted-program generation unit (16) which generates the converted program (tP) according to the generated randomized merger table.
摘要:
A signature generation apparatus preventing an transcript attack on signature data. The signature generation apparatus for generating signature data for message data (i) acquires, according to a predetermined acquisition method, a private key, which is different from a private key used in a previous digital signature operation, from among a plurality of private keys generated using a key generation method of a signature scheme in which the plurality of private keys correspond to a single public key, and (ii) performs, using the acquired private key, a digital signature operation on the message data according to a signature method of the signature scheme to generate the signature data.
摘要:
The present invention offers a prime calculating apparatus for achieving prime calculation where producing identical primes is avoided by simple management techniques. The prime calculating apparatus stores a known prime q and management information unique in the use range of primes. The prime calculating apparatus reads the management information; generates random information R based on the read management information; reads prime q; calculates prime candidate N, according to N=2×random information R×prime q+1, using the read prime q and generated random information R; tests whether the calculated prime candidate N is a prime; and outputs the calculated prime candidate N as a prime when the primality of the calculated prime candidate N is determined. Herewith, the prime calculating apparatus is able to calculate prime candidates from unique management information while avoiding producing identical primes.
摘要:
An encryption transmission apparatus and an encryption reception apparatus avoid attack that takes advantage of a re-transmission request. A server apparatus encrypts a content key five times, thereby generating five encrypted content keys, calculates a hash value of the content key, and transmits the five encrypted content keys and the hash value. An image playback apparatus receives the five encrypted content keys and the hash value, decrypts the five encrypted content keys thereby generating five content keys, calculates hash values, each corresponding to the generated content keys, and compares the calculated hash values with the received hash value, respectively. If at least one of the five calculated hash values matches the received hash value, the corresponding content key is considered correct. Conversely, if none of the five calculated hash values matches the received hash value, it is considered a decryption error.
摘要:
Provided is an obfuscating apparatus for making a program analysis more difficult. The obfuscating apparatus creates a table for inputting the same number of arguments, for multiplying and squaring operations, and sets the output values of the table so that the outputs may depend on those arguments. To the squaring operations, more specifically, there are added and tabulated the adding operations using the arguments necessary only for the multiplications, so that the number of arguments is equalized to that of the multiplications. In this case, moreover, the outputs depend on all the arguments, so that the presence/absence of the added argument is unknown unlike the case, in which dummy arguments not to be actually processed are added.
摘要:
A program obfuscating device for generating obfuscated program from which unauthorized analyzer cannot obtain confidential information easily. The program obfuscating device stores original program that contains authorized program instructions and confidential process instruction group containing confidential information that needs to be kept confidential, generates process instructions which, when executed in predetermined order, provide same result, with execution of last process instruction thereof, as the confidential process instruction group, inserts the process instructions into the original program at position between start of the original program and the confidential process instruction group so as to be executed in the predetermined order, in place of the confidential process instruction group, generates dummy block as dummy of the process instructions, and inserts the dummy block and control instruction, which causes the dummy block to be bypassed, into the original program, and inserts branch instruction into the dummy block.