A method for providing a code update on a memory-constrained device includes: determining, by a verifying entity, a minimum necessary compressed code space (MNCCS) of the code update; dividing, by the verifying entity, the code update into N chunks; encrypting, by the verifying entity, the N chunks, wherein encrypting the N chunks includes outputting at least one intermediate ciphertext block of each encrypted chunk, wherein the at least one intermediate ciphertext block of each encrypted chunk is permuted and permutation reference information is generated by the verifying entity; and sending, by the verifying entity, the encrypted chunks, the at least one intermediate ciphertext block of each encrypted chunk, and the permutation reference information to the memory-constrained device.