Patent ID: 8630422

Claim:
A method, comprising: receiving second information comprising first information encrypted under a second public key of an encryption scheme, where the first information comprises original information encrypted under a first public key of the encryption scheme, where the encryption scheme uses public key and secret key pairs and includes an encryption function, a decryption function and an evaluation function, where the encryption function operates to encrypt data using a certain public key, where the decryption function operates to decrypt data encrypted using the certain public key by using a certain secret key to obtain the data, where the encryption scheme is configured to evaluate at least one of the decryption function and an augmented version of the decryption function, where the augmented version of the decryption function comprises a circuit having at least two copies of the decryption function as inputs for a gate; receiving a first secret key encrypted under the second public key, where the first secret key corresponds to the first public key; and evaluating the second information by operating the evaluation function, where the evaluation function receives as inputs the second information, the first secret key encrypted under the second public key, the second public key and an input circuit, where the evaluation function outputs third information comprising the original information encrypted under the second public key of the encryption scheme.