A method and system for encrypting a plaintext logical data object for storage in a storage device operable with at least one storage protocol, creating, reading, writing, optimization and restoring thereof. Encrypting the plaintext logical data object comprises creating in the storage device an encrypted logical data object comprising a header and one or more allocated encrypted sections with predefined size; encrypting one or more sequentially obtained chunks of plaintext data corresponding to the plaintext logical data object thus giving rise to the encrypted data chunks; and sequentially accommodating the processed data chunks into said encrypted sections in accordance with an order said chunks received, wherein said encrypted sections serve as atomic elements of encryption/decryption operations during input/output transactions on the logical data object.