A method for executing a cryptography scheme with a computing entity and a trusted entity , the method comprising: transforming , at the trusted entity , a function P using a transformation P → T to a transformed function T, wherein the function P is NAND, wherein the function P is adapted to calculate an output plaintext pt o = P ( pt i ) from an input plaintext pt i of n bits, n=2, wherein the transformed function T is adapted to calculate an output ciphertext ct o = ct o , x ct o , y = T ct i = T ct i , x ct i , y = ⌊ 1 2 ct i , x + ct i , y ⌋ mod 2 from an input ciphertext ct i , wherein the transformation P → T includes calculating an encryption key k e with k e = (( k e , x ,0 , k e , x ,1 ), ( k e , y ,0 , k e , y ,1 )) = ((( t x + (( t x + t y ) mod 2)) mod 4,1 - 2(( t x + t y ) mod 2)), (( t y + (( t x + t y ) mod 2)) mod 4,1 - 2(( t x + t y ) mod 2))), k e being used for encrypting the input plaintext pt i , ct i = enc ( pt i , k e ) = (( k e , x ,0 + pt i , x · k e , x ,1 ) mod 4, ( k e , y ,0 + pt i , y · k e , y ,1 ) mod 4), and calculating a decryption key k d with k d = ⌊ 1 2 k e , x , 0 + k e , x , 1 + k e , y , 0 + k e , y , 1 ⌋ mod 2 , k d being used for decrypting the output ciphertext ct o , pt o = dec ( ct o , k d ) = ( ct o + k d ) mod 2, wherein the function P and a secret parameter set t = ( t x , t y ) are used to calculate the encryption key k e and the decryption key k d encrypting , at the trusted entity or at the trusted entity and the computing entity , the input plaintext pt i to the input ciphertext ct i using the encryption key k e , transmitting at least a part of the input ciphertext ct i being encrypted by the trusted entity from the trusted entity to the computing entity , and inputting the input ciphertext ct i into the transformed function T at the computing entity for calculating the output ciphertext ct o , wherein the encryption key k e and the decryption key k d are used only one time. transforming , at the trusted entity , a function P using a transformation P → T to a transformed function T, wherein the function P is NAND, wherein the function P is adapted to calculate an output plaintext pt o = P ( pt i ) from an input plaintext pt i of n bits, n=2, wherein the transformed function T is adapted to calculate an output ciphertext ct o = ct o , x ct o , y = T ct i = T ct i , x ct i , y = ⌊ 1 2 ct i , x + ct i , y ⌋ mod 2 from an input ciphertext ct i , wherein the transformation P → T includes calculating an encryption key k e with k e = (( k e , x ,0 , k e , x ,1 ), ( k e , y ,0 , k e , y ,1 )) = ((( t x + (( t x + t y ) mod 2)) mod 4,1 - 2(( t x + t y ) mod 2)), (( t y + (( t x + t y ) mod 2)) mod 4,1 - 2(( t x + t y ) mod 2))), k e being used for encrypting the input plaintext pt i , ct i = enc ( pt i , k e ) = (( k e , x ,0 + pt i , x · k e , x ,1 ) mod 4, ( k e , y ,0 + pt i , y · k e , y ,1 ) mod 4), and calculating a decryption key k d with k d = ⌊ 1 2 k e , x , 0 + k e , x , 1 + k e , y , 0 + k e , y , 1 ⌋ mod 2 , k d being used for decrypting the output ciphertext ct o , pt o = dec ( ct o , k d ) = ( ct o + k d ) mod 2, wherein the function P and a secret parameter set t = ( t x , t y ) are used to calculate the encryption key k e and the decryption key k d encrypting , at the trusted entity or at the trusted entity and the computing entity , the input plaintext pt i to the input ciphertext ct i using the encryption key k e , transmitting at least a part of the input ciphertext ct i being encrypted by the trusted entity from the trusted entity to the computing entity , and inputting the input ciphertext ct i into the transformed function T at the computing entity for calculating the output ciphertext ct o , wherein the encryption key k e and the decryption key k d are used only one time. <EOS>