摘要:
In the field of computer enabled cryptography, such as a keyed block cipher having a plurality of sequenced rounds, the cipher is hardened against attack by a protection process. The protection process uses block lengths that are larger or smaller than and not an integer multiple of those of an associated standard cipher, and without using message padding. This is operative in conjunction with standard block ciphers such as the AES, DES or triple DES ciphers, and also with various block cipher cryptographic modes such as CBC or EBC.
摘要:
A cryptographic process (such as the AES cipher) which uses table look up operations (TLUs) is hardened against reverse engineering attacks intended to recover the table contents and thereby the cipher key. This hardening involves removing any one-to-one correspondence between the TLU inputs and outputs, by altering the output of the TLU dynamically, e.g. at each execution (call) of the TLU. This is done by increasing the size of the tables, applying a dynamically determined mask value to the table input and/or output, or using an inverse of the table.
摘要:
Method and apparatus for obfuscating computer software code, to protect against reverse-engineering of the code. The obfuscation here is of the part of the code that performs a Boolean logic operation such as an exclusive OR on two (or more) data variables. In the obfuscated code, each of the two variables is first modified by applying to it a function which deconstructs the value of each of the variables, and then the exclusive OR operation is replaced by an arithmetic operation such as addition, subtraction, or multiplication, which is performed on the two deconstructed variables. The non-obfuscated result is recovered by applying a third function to the value generated by the arithmetic operation. This obfuscation is typically carried out by suitably annotating (modifying) the original source code.
摘要:
In the field of computer enabled cryptography, such as a keyed block cipher having a plurality of sequenced rounds, the cipher is hardened against an attack by a protection process which adds rounds to the cipher process. This is especially advantageous in a “White Box” environment where an attacker has full access to the cipher algorithm (process), including the algorithm's internal state during its execution. In one version, a specific number of rounds are added over those of a standard version of the cipher to both encryption and the complementary decryption. The added rounds are inserted immediately after the last of the standard rounds in the sequence. In another version, the added rounds are one or more opposing paired rounds of encryption/decryption or decryption/encryption which effectively cancel each other out, and may be inserted anywhere in the sequence of standard rounds.
摘要:
In the field of computer enabled cryptography, such as a cipher using lookup tables, the cipher is hardened against an attack by a protection process which obscures the lookup tables using the properties of bijective functions and applying masks to the tables' input and output values, for encryption or decryption. This is especially advantageous in a “White Box” environment where an attacker has full access to the cipher algorithm, including the algorithm's internal state during its execution. This method and the associated computing apparatus are useful for protection against known attacks on “White Box” ciphers, by obfuscating lookup table data, thereby increasing the cipher's complexity against reverse engineering and other attacks.
摘要:
In the field of computer enabled cryptography, such as a block cipher, the cipher is hardened against an attack by protecting the cipher key, by applying to it a predetermined linear permutation before using one key to encrypt or decrypt a message. This is especially advantageous in a “White Box” environment where an attacker has full access to the cipher algorithm, including the algorithm's internal state during its execution. This method and the associated computing apparatus are useful where the key is derived through a process and so is unknown when the software code embodying the cipher is compiled. This is typically the case where there are many users of the cipher and each has his own key, or where each user session has its own key.
摘要:
In the field of computer enabled cryptography, such as a keyed block cipher having a plurality of rounds, the cipher is hardened against an attack by a protection process which obscures the round keys using the properties of group field automorphisms and applying masks to the states of the cipher, for encryption or decryption. This is especially advantageous in a “White Box” environment where an attacker has full access to the cipher algorithm, including the algorithm's internal state during its execution. This method and the associated computing apparatus are useful for protection against known attacks on “White Box” ciphers, by eliminating S-box operations, together with improved masking techniques and increasing the cipher's complexity against reverse engineering and key storage attacks.
摘要:
In the field of computer enabled cryptography, such as a keyed block cipher having a plurality of rounds, the cipher is hardened against an attack by protecting the cipher key by means of a key expansion process which obscures the cipher and/or the round keys by increasing their lengths to provide an expanded version of the keys for carrying out encryption or decryption using the cipher. This is especially advantageous in a “White Box” environment where an attacker has full access to the cipher algorithm, including the algorithm's internal state during its execution. This method and the associated computing apparatus are useful where the key is derived through a process and so is unknown when the software code embodying the cipher is compiled. This is typically the case where there are many users of the cipher and each has his own key, or where each user session has its own key.
摘要:
In the computer data security field, a cryptographic hash function process embodied in a computer system and which is typically keyless, but is highly secure. The process is based on the type of randomness exhibited by well known table “cue sports” games such as billiards, snooker, and pool played on a billiards table involving the players striking one of a plurality of balls with a cue, the struck ball then hitting other balls, the raised sides of the table, and in some cases one or more balls going into pockets in the corners and/or sides of the table. Computation of the hash value (digest) is the result of providing a model (such as expressed in computer code) of such a game algorithm and using the message as an input to the game algorithm, then executing the game algorithm. A state of the game after a “shot” gives the hash digest value.
摘要:
In the computer data security field, this disclosure is of cryptographic hash function processes embodied in a computer system and which may be keyless, but are highly secure. The processes are based on the type of randomness exhibited by painting or drawing a picture. Computation of the hash value (digest) is the result of executing in computer code or logic circuitry an algorithm which models such a picture painting process using the message as an input to the picture painting algorithm, then executing the algorithm. A state of the resulting picture gives the hash digest value of the message. Message expansion or a derivation function (e.g., a pseudo random number generation process) may be applied to the message prior to execution of the picture painting process, for enhanced security.