Abstract: Methods, systems, and computer program products for secure distance computations are provided herein.

Abstract: Methods, systems, and computer program products for secure distance computations are provided herein.

Abstract: The present invention describes a method for authenticating a user of a mobile device by a verification authority, by making use of at least a personal identification number (PIN) and at least one cryptographic key, such that the PIN and the cryptographic key is known only to the user and the verification authority. The cryptographic key has at least one session key. Firstly, the user encodes the PIN by using at least one session key and then transfers the encoded PIN to a predefined address of the verification authority via the mobile device. Next, the verification authority decodes the PIN by using the cryptographic key authenticates the user if the decoded PIN matches a PIN stored corresponding to the user.

Abstract: The present invention describes a method for authenticating a user of a mobile device by a verification authority, by making use of at least a personal identification number (PIN) and at least one cryptographic key, such that the PIN and the cryptographic key is known only to the user and the verification authority. The cryptographic key has at least one session key. Firstly, the user encodes the PIN by using at least one session key and then transfers the encoded PIN to a predefined address of the verification authority via the mobile device. Next, the verification authority decodes the PIN by using the cryptographic key authenticates the user if the decoded PIN matches a PIN stored corresponding to the user.

Abstract: Users make online purchases using a virtual currency. A series of secret encryption keys is generated, where each key in the series is associated with a different epoch. A token tracking table is initialized. Whenever real currency is received from a user wanting to purchase tokens, a semantically secure encryption method is used in conjunction with the secret encryption key in the series that is associated with the current epoch to generate a set of encrypted tokens which includes one or more encrypted paid tokens. The set of encrypted tokens is sent to the user wanting to purchase tokens, and each encrypted paid token in the set is entered into the token tracking table, where the entry for each encrypted paid token includes information specifying that the token has not yet been spent and has not yet been encashed.