Patent ID: 7424617

Claim:
A method for verifying the validity of an encrypted code generated in base L, the method comprising: obtaining an encrypted code from a user, that when decrypted is determinable to indicate a value-in base L, the encrypted code obtained by appending a third string, which is an output of applying an encryption algorithm employing a second secret code to a second string composed of an n-bit raw number and an in-bit validation number, the in-bit validation number generated by hashing, with a hash function, a first string with a first secret code, the first string composed of the n-bit raw number and the first secret code; converting the encrypted code to a base 2 string; decrypting the base 2 string using the second secret code to generate a recovered second string; hashing, with the first secret code, an n-bit portion of the recovered second string concatenated with the first secret code to generate a second in-bit validation number; comparing the remaining in-bits of the recovered second string with the second m-bit validation number to verify the validity of the encrypted code; and if valid then crediting the user with the value indicated by the decrypted code, wherein n=32 and m=16.