1. Confidential Data Storage and DeletionPRESENTEDByA.KIRAN KUMAR(08581A0526)

2. C O N TEN TS Introd uction C onfid ential D ata Storage Techniques of confid ential storage Encryption Sym m etric and asym m etric encryption Ad vanced Encryption Stand ard (AES) H ard ware-based C onfid ential Storage techniques C onfid ential D ata Erasure Physical D estruction D ata O verwriting Encryption with K ey Erasure 2 C onclusion 3. INTRODUC TION Many computers store data about personal finances, online transactions,tax records, passwords for bank accounts and emails. All these sensitive information are vulnerable to theft and also leakedaccidentally due to improper disposal of storage media. To protect the secrecy of the entire data lifetime, we must haveconfidential ways to store and delete data. This seminar describes the most commonly used encryptionalgorithm, Advanced Encryption System (AES) which is used formany of the confidential data storage methods and also describes theconfidential data erasure methods such as physical destruction, dataoverwriting methods and Key erasure.3 4. C ONFIDE NTIA L DA TASTORA GE Achieving confidentiality means storing data in a way that can be readonly by authorized persons. No unauthorized persons should be able toread or otherwise obtain meaningful information from this data, evenwith physical access to the storage media.UNIX Storage PathWindows Storage Path ApplicationApplication UserKernelVFSI/O ManagerFile SystemFile System Driver Storage Device Block Layer Drivers 4Storage StorageMedia Media 5. TECHNIQUES OF CONFIDENTIALSTORAGE There are two basic techniques of confidential storage: 1. Software-based confidential storage techniquesI. Encryption II. Advanced Encryption Standard (AES)2. Hardware-based confidential storage techniques I. Secure Flash Drives II. Enclosures and Extension Cards III. Encrypted Hard Drives 5 6. STO RAGE E NC RYPTION Encryption is the process of transforming information (referred toas plaintext) using an algorithm (called cipher) to make itunreadable to anyone except those possessing special knowledge,usually referred to as a key. There are two basic techniques for encrypting information. 1. Symmetric encryption (secret key encryption) 2. Asymmetric encryption ( public key encryption). 6 7. SYM M ETRIC AN D ASYM M ETRICEN C RYPTIO N7 8. A DVA NC E D E NC RYPTION STA NDA RD (A E S) The Advanced Encryption Standard (AES)specifies a FIPS(FederalInformation Processing Standard)-approvedcryptographic algorithmthat can be used to protect electronic data.The AES algorithm is asymmetric block cipher that can encrypt(encipher) and decrypt(decipher) information. 128 bit plain textKRound Keys (128 Bits)E Pre Round Transformation Y Cipher KeyK0 (128, 192 or 256 bits)Round 1EK1X Nr Key SizePRound 2K2A10 128.... .N12 192 Round N (Slightly Different) .S KNrI14 256O 8 128 bit cipher textN 9. H ARD WARE-BASED C O N FID EN TIAL STO RAGE TEC H N IQ U ES Secure Flash Drives: Some secure flash drives provide onlysoftware encryption using block-based encryption methods asmentioned. Other flash drives protect data through cryptographicmechanisms provided on the flash drive itself. Enclosures and Extension Cards: Enclosures and extensioncards can employ good encryption techniques and do not divulge anyinformation about files or the structure of the file system on disk. Encrypted Hard Drives: Seagate [2006] is introducing DriveTrust Technology into their Momentus 5400 FDE series notebookhard drives, which implement full disk encryption. This technology isimplemented in the hard drive firmware and provides encryption,decryption, hashing (for passwords), digital signature, and random-9number generation functions. 10. CONFIDENTIAL DATA ERASURE When confidential data have to be removed, we must be sure that oncedeleted, the data can no longer be restored. A full secure data lifecycleimplies that data is not only stored securely, but deleted in a securemanner as well. CMRR scanning microscopes , Magnetic force microscopy andmagnetic force scanning & tunneling microscopy analyze the polarityof the magnetic domains of the electronic storage medium and canrecover data in minutes. Confidential data deletion can be accomplished in three ways: 1.Physical Destruction 2.Data Overwriting 3.Encryption with Key Erasure10 11. PH YSIC AL D ESTRU C TIO N The Department of Defense government document(DoD)states thatclassified material may be destroyed by numerous methods: 1. Smelting 2. Shredding 3. Sanding 4. Pulverization 5. Acid bath 6. Magnetic degaussing Physical destruction methods provide great confidentiality. we cannotsecurely delete only one file using these methods. Therefore, thismethod does not support flexible security policies. Since physical destruction can destroy large amounts of data in a 11relatively short amount of time, the performance in this sense is quitegood. 12. DATA OVERWRITING Write new data on top of existing data and thus erase thepreviously existing data. The Department of Defense document suggests an overwrite with acharacter, its compliment, then a random character, as well as othersoftware-based, overwrite methods that refer to non-volatile electronicstorage as listed below:IDERASURE METHODC Overwrite all addressable locations with a characterD Overwrite all addressable locations with a character, itscomplement, then a random character and verifyE Overwrite all addressable locationswith acharacter, itscomplement, then a random characterH Overwrite all locations with a random pattern, with binary zeros,and then with binary ones12 13. ENCRYPTION WITH KEY ERASURE The third way to delete data securely is to encrypt the data and thensecurely erase the key. The encryption key is often securely deletedusing overwriting methods. This combination allows for much fastersecure deletion in that only a small key is overwritten instead of theentire file (which could be very large). if the encryption key is protected by a password and the password ismerely forgotten, the strength of the secure deletion is directlycorrelated to the strength of the password. It is best to delete the encryption key(s) securely through physicaldestruction or overwriting methods. The ease-of-use characteristic isdegraded in that the user must destroy the key explicitly. 13 14. C O N C L U SIO N This Seminar took a look at the methods, advantages, and limitations ofconfidential storage and deletion methods for electronic media in a non-distributed, single-user environment, with a dead forensic attack model. We compared confidential data handling methods using characteristicsassociated with confidentiality, policy, ease-of-use, and performance. By compiling experiences and constraints of various confidential storageand deletion techniques, we hope that knowledge from this Seminar isvery helpful.t 14 15. 15