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.