Dissemination of knowledge on Secure Systems Engineering
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This document provides an overview of topics related to secure systems engineering including cryptography, digital signatures, blockchains, and privacy technologies. It discusses cryptography concepts like symmetric and asymmetric encryption. Digital signatures are explained as a method to authenticate messages using public/private key pairs. Blockchains are described as a method to securely record transactions in a distributed ledger using hashes. Privacy-preserving technologies like zero-knowledge proofs, Zcash, and garbled circuits are also introduced.
Dissemination of knowledge on Secure Systems Engineering
- 1. Dissemination of knowledge on Secure Systems Engineering JAI GANESH S Asst.Professor – Dept. of ECE RMKCET
- 2. Topics Overview • What is Cryptography • Zero Knowledge proof • Digital Signatures • BIT Coins & Block Chains • Architectural aid to secure systems • Z-cash • Garbled Circuits • Canaries & Confinement
- 3. Cryptography – Art of Keeping Secret
- 4. Cryptography • Practice of Studying / Developing Algorithms to keep the data secret. • Or in other words “ constructing protocols that prevents the third parties from reading private messages” • Or in other words “Enabling the exchange of confidential data in the presence of adversaries”
- 5. Simple science behind cryptography When Julius Caesar sent messages to his generals, he didn't trust his messengers. So he replaced every A in his messages with a D, every B with an E, and so on through the alphabet. Only someone who knew the "shift by 3" rule could decipher his messages.
- 6. How Cryptography Works? •Plain Text •Cipher Text •Encryption •Decryption •Key
- 7. Aspects of Cryptography • Confidentiality – Keeping the Secret • Integrity – Maintaining the Accuracy and Consistency of the data • Authentication - the process or action of proving or showing something to be true, genuine, or valid.
- 9. Symmetric Key Encryption • Secret key cryptography methods employ a single key for both encryption and decryption. • the sender uses the key to encrypt the plaintext and sends the cipher text to the receiver • The receiver applies the same key to decrypt the message and recover the plaintext.
- 10. Sub categories of Symmetric Cryptography - DES • Stream ciphers – Bit by Bit Encryption – Caesar Cipher and Substitution Cipher • Block ciphers – Group of bits Encryption – Feistel Cipher, Lai–Massey ciphers, Blowfish
- 11. Asymmetric Key Encryption • Uses pairs of Keys – Public Key - which may be disseminated widely – Private Key - which are known only to the owner “where the public key verifies a holder of the paired private key sent the message, and encryption, where only the paired private key holder can decrypt the message encrypted with the public key.”
- 12. Sub categories of Asymmetric Cryptography - AES • RSA Algorithm • Diffie-Hellman • Digital Signature Algorithm (DSA) • ElGamal • Elliptic Curve Cryptography
- 14. How it works? • Step 1 – Calculate Message Digest
- 15. • Step 2: Calculate the Digital Signature hash-value of the message (the message digest) is encrypted with the private key of the person who signs the message called digital signature
- 16. Verifying Digital Signatures • Step 1: Calculate the Current Hash-Value – the same hashing algorithm is used as was used during the signing process. The obtained hash-value is called the current hash-value • Step 2: Calculate the Original Hash-Value – The decryption is done by the public key that corresponds to the private key used during the signing of the message. As a result, we obtain the original hash-value • Step 3: Compare the Current and the Original Hash- Values – we compare the current hash-value obtained in the first step with the original hash-value obtained in the second step. If the two values are identical, the verification if successful
- 18. Applications of Digital Signatures • Electronic mail • Data storage • Electronics fund transfer • Software distribution • Smart cards • Time stamped signatures (To check Validity)
- 19. Zero Knowledge Proof • zero-knowledge protocol is a method by which one party (the prover) can prove to another party (the verifier) that a given statement is true, without conveying any information apart from the fact that the statement is indeed true. • zero-knowledge proofs require interaction between the individual (or computer system) proving their knowledge and the individual validating the proof.
- 20. Understanding Zero Knowledge Peggy randomly takes either path A or B, while Victor waits outside
- 21. Victor chooses an exit path
- 22. Peggy reliably appears at the exit Victor names
- 23. Properties of ZKP • A zero-knowledge proof must satisfy three properties – Completeness: if the statement is true, the honest verifier (that is, one following the protocol properly) will be convinced of this fact by an honest prover. – Soundness: if the statement is false, no cheating prover can convince the honest verifier that it is true, except with some small probability. – Zero-knowledge: if the statement is true, no cheating verifier learns anything other than the fact that the statement is true. In other words, just knowing the statement (not the secret) is sufficient to imagine a scenario showing that the prover knows the secret.
- 24. Variants of zero-knowledge • Perfect zero-knowledge • Statistical zero-knowledge • computational zero-knowledge
- 25. Applications • Authentication systems – one party wants to prove its identity to a second party via some secret information (such as a password) but doesn't want the second party to learn anything about this secret. • Ethical behavior – the idea is to force a user to prove, using a zero- knowledge proof, that its behavior is correct according to the protocol • Blockchains – ZKPs can be used to guarantee that transactions are valid
- 27. Bit Coins • Satoshi nakamoto invented the bit coins. • Mined over 2 crore bit coins. Person or community who solves a hash function will get one bit coin. • As on 2017 - 1 crore bit coins have been identified
- 28. Bit Coins • It’s a kind of cryptocurrency – Meaning it is encrypted and cannot be copied • Peer to peer electronic cash system • Virtual money to buy and sell things online • Transactions of the bit coins are recorded in a block chain • Will be the future of economics in digital world
- 29. Block Chains
- 30. Block Chains • Block chains are the chain of blocks that contains information • Originally introduced in 1991 for timestamping digital documents • Later in 2009 used by satoshi nakamoto used this to create digital ledger of bitcoins • Once the data recorded in the ledger it becomes very difficult to change it.
- 31. Contents of a block in block chain
- 32. Data – contains the details of the transaction
- 33. Hash – Equal to the Message Digest if there is any change in the content then the hash changes
- 34. Hash of the previous block – which actually makes the blockchain more secure
- 35. Example
- 36. If there is any tampering in any block that eventually affects all other remaining blocks Computers now a days have high computational power to calculate the hash for remaining blocks to accept the tampering – overcome by Proof of Work
- 37. Other Exposures • Z Cash – an alternative to Bit coins introduced in 2016 • Garbled Circuits – New Technology that talks about Secure Multi Party Computation • Canaries – Technology that talks about running a Vulnerable program in a Secure System • Confinement – An Alternative to Canaries • Architectural Aid to Secure Systems – Hardware perspective of secure systems (CISC and RISC Architectures)