Abstract: A quantum key distribution (QKD) system is provided that makes use of a quantum signal of polarized photons and comprises a QKD device and complimentary QKD apparatus. The QKD device has a QKD subsystem comprising one of a QKD transmitter and receiver for inter-working with a complimentary QKD receiver or transmitter of said apparatus. The device also has an alignment subsystem arranged to wirelessly interact with the QKD apparatus to enable generation of user feedback and/or adjustment signals for use in aligning the QKD transmitter and receiver such that the QKD transmitter is pointing at the QKD receiver and the polarization axes of the QKD transmitter and receiver are aligned.

Abstract: A quantum key distribution (QKD) method involves the sending of random data from a QKD transmitter to a QKD receiver over a quantum signal channel, and the QKD transmitter and receiver respectively processing the data transmitted and received over the quantum signal channel in order to seek to derive a common random data set. This processing is effected with the aid of messages exchanged between QKD transmitter and receiver over an insecure classical communication channel. The processing concludes with a check, effected by an exchange of authenticated messages over the classical communication channel, that the QKD transmitter and receiver have derived the same random data set. At least some of the other messages exchanged during processing are exchanged without authentication and integrity checking. A QKD transmitter and QKD receiver are also disclosed.

Abstract: In carrying out a task that consumes data from a one-time pad, task inputs comprising at least first data and second data from the pad, are combined together to form an output from which the data used from the pad cannot be recovered without knowledge of at least one of the first and second data. The task concerned can be, for example, the encrypting of a message or the creating of an attribute verifier.

Abstract: A secure transaction method is provided for publicly-accessible transaction terminals. The method uses quantum key distribution (QKD) between a hand-portable QKD device and a complimentary QKD apparatus incorporated the transaction terminal. After the QKD device has been brought up to the transaction terminal, the QKD device and the complimentary QKD apparatus of the terminal are is used to provide the device and terminal with new secret shared random material. The new secret shared random material is then used to establish a secure classical communication channel between the device and transaction terminal for conducting a transaction. An ATM terminal and POS terminal that use quantum key distribution are also disclosed.

Abstract: An identifier-based public/private key pair is generated for a first party with the involvement of a trusted authority that has an associated secret. An identifier of the first party is signed by the trusted party to produce a multi-component signature. This signature is converted into the first-party identifier-based key pair; the private key of this key pair comprises a component of the signature provided confidentially to the first party, and the public key being formed using at least another component of the signature and the first-party identifier. The signature used by the trusted authority is, for example, a Schnorr signature or a DSA signature.

Abstract: Identifier-based signcryption methods and apparatus are disclosed both for signing and encrypting data, and for decrypting and verifying data. The signcryption methods use computable bilinear mappings and can be based, for example, on Weil or Tate pairings. A message sender associated with a first trusted authority carries out integrated signing/encryption processes to send a signed, encrypted message to an intended recipient associated with a second trusted authority. The recipient then carries out integrated decryption/verification processes to recover the original message and verify its origin.

Abstract: There is described a device for the non-invasive measurement of one or more analytes in blood in a patient's body part which comprises a light transmitter comprising a plurality of transmitting fibres positioned to transmit light to the body part and a light detector comprising a plurality of light detector fibres position to detect light transmitted through or reflected from the body part. The device especially utilises the non-pulsatile element of a patient's blood. There is also described a method of measuring blood glucose levels and a device programmed so as to calculate one or more of the haemoglobin index, the oxygen index and the blood oxygen saturation.

Abstract: A cryptographic method and apparatus is provided in which an identifier-based encryption process is used to encrypt a message with an identifier string that specifies conditions to be checked by a trusted entity before providing a decrypted form of the encrypted message, or enabling its decryption. A further trusted entity is used to verify the identity of the message sender as indicated by a further identifier string, and to provide the sender with a secret key that the sender uses to generate complimentary signature components. These signature components are sent along with the encrypted message and are used, along with other data including the first identifier string and a public key of the further trusted entity, to authenticate the identity of the message sender.

Abstract: A cryptographic method and apparatus is provided in which a first party receives and modifies a public key for which there exists a corresponding private key held by a second party. The public key is modified by exponentiating at least one element of the received public key using as exponent a hash of a string that comprises information concerning at least one action to be taken by the second party. The string is made available to the second party to enable the latter to modify its private key to compliment the modified public key. In a preferred embodiment, the method and apparatus are applied to the use of the ElGamal encryption/decryption scheme, with the second party acting as a trusted authority that only releases the decrypted message to a third party if the latter satisfies an identity condition specified in the string.

Abstract: An apparatus for the measurement of at least one analyte in the blood of a patient, which includes a light source generating broadband light and a light-transmission arrangement having a plurality of transmitting fibers is positioned for simultaneously transmitting multiple wavelengths of the broadband light from the light source to the blood of the patient. The measurement apparatus further includes an optical fiber arrangement having a plurality of light detector fibers for leading multi-wavelength light, in spectrally unseparated form, transmitted through, or reflected from, the blood and a light detection arrangement for receiving the multi-wavelength light in its spectrally unseparated form from the optical fiber arrangement, for spectrally decomposing the received light, and for determining amplitudes of selected wavelengths of the decomposed light.

Abstract: A smartcard is provided that stores a secret associated with the user of the card. The smartcard is arranged to map an input string to a first element of an algebraic group according to a known mapping function, to multiply the first element by the stored secret to form a second element of the same algebraic group such that there exists a computable bilinear map for the first and second elements, and to output this second element. This selection of the limited functionality of the smartcard enables it to be employed in the provision of a range of cryptographic services such as encryption, decryption and signature generation. The smartcard is therefore suitable for use in an organisation where multiple cryptographic services are required.

Abstract: Data to be output to a removable storage medium is encrypted for sending to an output device by an encryption process based on encryption parameters comprising public data of a trusted party and an encryption key string comprising a policy for allowing the output of the data. The trusted party provides a decryption key to the output device but only after being satisfied that the policy has been met. The decryption key is generated in dependence on the encryption key string and private data of the trusted party. The output device uses the decryption key in decrypting the data to be output. Embodiments are provided that involve multiple policies and trusted parties.

Abstract: A trusted authority is provided for identifier-based cryptography. The trusted authority has a secret and derives first and second elements at least the second of which it publishes. The first element is derived from an identifier associated with the trusted authority; the second element is a combination of the first element and the secret. The trusted authority provides a private-key generation service involving the generation of a private key for a third party in dependence on the secret and an identifier string associated with that third party.

Abstract: A method and apparatus are provided for the secure provision of payload data that comprises image data representing an image. The payload data is encrypted using encryption parameters comprising public data of a trusted party and an encryption key string. The encryption key string comprises thumbnail data that represents a low-resolution version of the image represented by the image data. The encryption key string preferably also comprises at least one condition to be met before the trusted party releases a decryption key for decrypting the encrypted payload data; advantageously, the apparatus enables a user to select, via a user interface, one or more conditions for incorporation into the encryption key string. The functionality for generating the thumbnail data, for choosing the conditions to be used for the encryption key string, and for encrypting the payload data is preferably incorporated into a physical add-in module such as a PCMCIA card.

Abstract: When sending personal data to a recipient, the data owner encrypts the data using both a public data item provided by a trusted party and an encryption key string formed using at least policy data indicative of conditions to be satisfied before access is given to the personal data. The encryption key string is typically also provided to the recipient along with the encrypted personal data. To decrypt the personal data, the recipient sends the encryption key string to the trusted party with a request for the decryption key. The trusted party determines the required decryption key using the encryption key string and private data used in deriving its public data, and provides it to the requesting recipient. However, the decryption key is either not determined or not made available until the trusted party is satisfied that the associated policy conditions have been met by the recipient.

Abstract: First data is encrypted by a first party using an encryption key string formed using at least a hash value of the first data, this hash value being either in clear or in an encrypted form enabling its recovery in clear by a trusted party. The encrypted first data and the encryption key string are made available to a second party which forwards the encryption key string to the trusted party. The trusted party carries out at least one check on the basis of data contained in the encryption key string and, if the checks are satisfactory, provides a decryption key to the second party. Where the encryption key string comprises the hash value of the first data in encrypted form, the trusted party will typically decrypt the hash value and pass it to the second party to enable the latter to check the integrity of the first data.

Abstract: First data to be sent by a first party to a second party is encrypted using an encryption key that is formed using at least a hash value generated by a keyed hash of at least one condition that typically serves as an identifier of an intended recipient of the first data. The encrypted first data is provided to a data recipient who requests a decryption key from the trusted party. The trusted party is responsible for verifying that the recipient meets the specified conditions before providing the decryption key. A valid decryption key is only provided if the correct conditions have been supplied to the trusted party.

Abstract: An RSA cryptographic method and system is provided in which a sender encrypts a message (m) using a public modulus n, and an encryption exponent e that is a function of a sender-chosen string. This function is such that the values of e generated by it will not be coprime. In a preferred embodiment, a recipient receives the encrypted message and subjects it to a modulo-n blinding operation. The resultant blinded encrypted message is then made available to a trusted authority which decrypts it using a decryption exponent d based on the sender-chosen string and private data associated with the public modulus; however, the blinding applied to the message prevents the trusted authority from reading the message. The decrypted, but still blinded, message is passed back to the recipient who cancels the blinding to recover the message.

Abstract: First data to be sent by a first party to a second party is encrypted using an encryption key string formed using at least a hash value generated using second data and a secret, shared with a trusted party, that serves as identification of the first party. The second data comprises, for example, one or more conditions that serve as identifiers of the second party, and a hash-value element generated by hashing the first data. The encrypted first data and the encryption key string is made available to the second party which forwards the encryption key string to the trusted party with a request for the corresponding decryption key. The trusted party carries out at least one check on the basis of data contained in the encryption key string and, if this at least one check is satisfactory, provides a decryption key to the second party.

Abstract: First data to be sent by a first party to a second party is encrypted using public data of a trusted party and an encryption key string formed using at least a hash value generated by hashing at least one condition that typically serves as an identifier of an intended recipient of the first data. The encrypted first data is provided to a data recipient who requests a decryption key from the trusted party. The trusted party is responsible for verifying that the recipient meets the specified conditions before providing the decryption key. A valid decryption key is only provided if the correct conditions have been supplied to the trusted party.