Abstract: Elliptical curve based cryptographic algorithms are public key algorithms offering a shorter calculation time and smaller key sizes in comparison with RSA. In a smart card type environment, these algorithms are vulnerable to differential power analysis (DPA) attacks. The disclosed invention provides a countermeasure procedure enabling positive action to be taken against DPA-type attacks. The countermeasure does not reduce performance and is easy to use in a smartcard type component.

Abstract: Two methods for random number generation are modified to make them more resistant to attacks by current measurements. The methods are particularly designed to be implemented in electronic devices such as smart cards, PCMCIA, badges, contactless cards or any other portable device. The DES algorithm is encrypted using a key K having a value D representing date information, to generate an integer variable I. For j ranging from 1 to m, the following steps are carried out: substituting s with s XOR I; introducing in the integer variable y the result of the encryption of s with the DES algorithm using the key K; introducing in xj the result of y or s; substituting s with y XOR I; and introducing in s the result of the encryption of s with the DES algorithm using the key K. The sequence (x1, x2, xm) is then restored in the output.

Abstract: A countermeasure method in an electronic component which uses an RSA-type public key cryptographic algorithm. A first countermeasure method uses a random calculation for each new execution of the decryption algorithm with CRT. The calculations are made modulo p*r and q*t, r and t being random numbers. A second countermeasure makes the recombination random using the CRT theorem.

Abstract: An encryption method in which a clear message (m) is formatted with a formatting function (p), and in which the result of the formatting step is exponentiated using a public key (N, e) in accordance with the relationship c=?(m)e mod N, c being an encrypted message, ?(m) being the result of the formatting step, and e and N elements of the public key. The formatting function (?) is the PSS function. The invention is applicable to cryptography, for example of RSA type, for smart cards for instance.

Abstract: The invention concerns a method for testing sources generating random numbers, particularly sources set up in the context of cryptographic systems such as random number generators incorporated in chip cards. The invention is particularly designed to be used for testing and validating electronic devices such as chip cards, PCMCIA, badges, contactless cards or any other similar portable apparatus.

Abstract: A method and associated device for checking a biometric signature by a simple and secure calculation adapted to personal objects of the chip card type. The method is based on the storage within the object of an obscured biometric signature and an associated authentication code. A terminal capturing a fingerprint compares the fingerprint data with the obscured biometric signature transmitted by the card and transfers the result of this comparison to the chip card, which validates this result with the authentication code.

Abstract: There exist numerous public key probabilistic encryption algorithms. Most of said algorithms do not have a maximum security level against someone capable of chosen ciphertext attacks. The method consists in a construct enabling to enhance the security of any public key probabilistic or deterministic encryption algorithm to achieve optimal security level.

Abstract: The RSA enciphering algorithm is the most widely used public key enciphering algorithm.

Abstract: The invention concerns a cryptography method for generating probabilistic digital signatures and/or for a key-exchange a protocol and/or for an encryption algorithm, said method being based on the use of a public key algorithm on abnormal binary elliptic curve (E) (Koblitz curve) whereon a point P (x, y) is selected, pairs (ki, Pi) being stored with Pi the point corresponding to the scalar multiplication of the point P by ki, said method comprising steps which consist in generating a random variable (k) and in calculating a point C corresponding to the scalar multiplication of P by k (C=k.P). The invention is characterised in that the generation of said random variable (k) and the calculation of the point C are performed simultaneously.

Abstract: The RSA enciphering algorithm is the most widely used public key enciphering algorithm. The invention consists of defining a method for considerably reducing the size of the signatures to be transmitted. The invention can be used easily in an electronic component of the smart card type.