Abstract: Digital polymers have emerged as a promising medium for data storage. Equally critical yet challenging is information security, which remains hindered by the lack of efficient encryption techniques. Herein, we report a cascaded encryption/decryption strategy. Block digital polymers (DigP-10_n-b-FPOSS), consisting of discrete poly(γ-butyrolactone) (PγBL) and fluorinated polyhedral oligomeric silsesquioxane (FPOSS) blocks, were synthesized via an iterative approach combining esterification and thiol-ene click chemistry, enabling sequence-information encryption (first-level encryption). Leveraging the chemical incompatibility between PγBL and FPOSS segments, morphological information from self-assembly was further encrypted (second-level encryption). The morphology code is decrypted by small-angle X-ray scattering (SAXS) (first-level decryption), and the sequence code by tandem mass spectrometry (MS/MS) (second-level decryption). Correct information can only be retrieved through two consecutive decryption steps, thus affording enhanced information security and a new paradigm for secure data storage.