Crypto for Hackers. Eijah. v1.00 August 7 th, 2015
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1
2 Crypto for Hackers Eijah v1.00 August 7 th, 2015
3 Hello World Shall we play a game? Joshua/WOPR
4 Who am I? Founder Programmer Hacker 4
5 Last year at Defcon Saving Cyberspace by Reinventing File Sharing We re losing out right to privacy and free speech The abuse of power by the strong The more I thought about this Security, anonymity, privacy Foundation of strong crypto But crypto is really difficult Lifelong dedication Can we filter out the noise? Can we make it easy to understand? Convenience We can do anything if we put our minds to it Trust Change Control 5
6 Importance of Crypto "Know thy self, know thy enemy. A thousand battles, a thousand victories. Sun Tzu, general and author of The Art of War
7 A World without Secrets Imagine for a moment A dangerous and fragile world We cannot survive without privacy People Governments Corporations The irony In the news Why don't governments want us to protect our data? Lack of transparency doesn t imply treachery 7
8 A Formidable Ally AA856A1BA814AB99FFDEBA6AEFBE1C04 Crypto is our strongest weapon Considered a military weapon in the USA until 1992 Many different uses Protect out secrets Expose the secrets of others Poor crypto implementations A common denominator to the Internet 8
9 Know Thy Enemy In the past Times have changed Understanding the weapons and attack vectors Betting everything on crypto Our mission Understand crypto Embrace it in our daily lives Become more powerful than those who oppress us 9
10 Becoming More Powerful Technology as the deciding factor We are stronger than governments & corporations Crypto is a complex and difficult subject The secret Ubiquitous Pervasive Easy The will of the people Battle cry for a new generation of hackers 10
11 The Algorithms Encryption is the defense against the dark arts. Edward Snowden
12 Terminology Crypto(graphy) The practice and study of techniques for secure communication in the presence of third-parties. Cipher An algorithm for performing encryption or decryption. Encryption, Decryption The process of encoding messages or information in such a way that only authorized parties can read it (and vice versa). Plaintext, Cleartext Unencrypted messages or information. Ciphertext Unencrypted messages or information. Pseudorandom Function (PRF) Efficient function that maps input and random seed to an output that looks random 13
13 Terminology 14 Key A parameter that determines the functional output of a cryptographic cipher. Hash (Function) A 1-way cryptographic conversion function which is considered practically impossible to invert. (Message) Digest The output of a hash function. Symmetric Encryption Algorithm Algorithms that use the same cryptographic keys for both encryption of plaintext and decryption of ciphertext. Asymmetric Encryption Algorithms that use different cryptographic keys for encryption of plaintext and decryption of ciphertext.
14 Crypto Libraries 15 Crypto++ Free C++ class library of cryptographic schemes Demoncrypt Open-source C++ wrapper around the most important Crypto++ algorithms. Crypto foundation of demonsaw v2.0 Algorithms Ciphers (AES) Hash (MD5, SHA) HMAC Key Agreement Schemes (Diffie Hellman) Password-based Key Derivation Functions (PBKDF2)
15 Ciphers Algorithm for performing encryption or decryption Plaintext ciphertext Ciphertext plaintext Usages Symmetric, Asymmetric Everywhere (Software, hardware, networking, databases, DRM, etc.) Algorithms Rijndael (AES), Serpent, Twofish, RC6, MARS 128, 192, 256 bit keys Notes NIST AES Standardization Process 16
16 Ciphers AES // Derive Key pkcs5_pbkdf2_hmac_sha256 pbkdf; pbkdf.set_salt("demonsaw 2.0"); string key = pbkdf.compute("believe in the Right to Share ); // AES cipher.set_key(key); string ciphertext = cipher.encrypt("the Cloud is a lie"); cout << "CIPHERTEXT: " << hex::encode(ciphertext) << endl; // 542f25fcf9c bee34d1122fab30c349c7d7ded1967c5ff3abac42f734b 17 string plaintext = cipher.decrypt(ciphertext); cout << "PLAINTEXT: " << plaintext << endl; // The Cloud is a lie
17 Hash Functions 18 One-way conversion function Message (Message) Digest Practically impossible to reverse engineer Fixed sized output w/ optional salt Usages Verify file integrity, hashing passwords, digital signatures Checksums, keyed data structure indexes Algorithms MD5, SHA-1, SHA-2, SHA-3 Concerns Collisions (limited key space) Rainbow attacks Length extension hacks
18 Hash Functions MD5 md5 md; string md5_digest = md.compute("the Cloud is a lie"); cout << "MD5: " << md5_digest << endl; // b250e2031c5257c01382a21 SHA512 sha256 sha; string sha256_digest = sha.compute("the Cloud is a lie"); cout << "SHA256: " << sha256_digest << endl; // 6aad0fcc90862e6b3c5cea078a0a35c0327f fc5689abaa5f783c8cdf 19
19 Hash-Based Message Authentication Codes 20 Hash function with a user-provided key Message Authentication Code (MAC) Provides authenticity & message integrity Prevents rainbow attacks Key is not in hash Usages Can be used in place of hashes Building block for other applications (PBKDF2) Signing messages Algorithms MD5, SHA-1, SHA-2, SHA-3 Concerns Strength of the input key
20 Hash-Based Message Authentication Codes HMAC MD5 hmac_md5 hmac; hmac.set_key("believe in the Right to Share"); string md5_mac = hmac.compute("the Cloud is a lie"); cout << "HMAC MD5: " << hex::encode(md5_mac) << endl; // 888e3e9cedd4f1a0d9a7c6e76af16afa 21 HMAC SHA512 hmac_sha256 hmac; hmac.set_key("believe in the Right to Share"); string sha256_mac = hmac.compute("the Cloud is a lie"); cout << "HMAC MD5: " << hex::encode(sha256_mac) << endl; // cb1fa1e58e17a6b8c87e476e e114b5cd51b20946facca15cc497595f1
21 Password-Based Key Derivation Functions Generating a key from a password/phrase Convert user-friendly strings into keys Choose PRF, salt, iterations, output size Usages Mutual shared secret derivation Input for other crypto algorithms Algorithms PBKDF2 Concerns Computationally more intense Character encoding is important 22
22 Password-Based Key Derivation Functions PBKDF2 HMAC MD5 pkcs5_pbkdf2_hmac_md5 pbkdf; pbkdf.set_salt("demonsaw 2.0"); string key = pbkdf.compute("believe in the Right to Share"); cout << "PBKDF2 HMAC MD5: " << hex::encode(key) << endl; // 0552acc1243e62c9c35acdcbc6714f30 PBKDF2 HMAC SHA512 pkcs5_pbkdf2_hmac_sha256 pbkdf; pbkdf.set_salt("demonsaw 2.0"); string key = pbkdf.compute("believe in the Right to Share"); cout << "PBKDF2 HMAC SHA256: " << hex::encode(key) << endl; // b1403d dc580eb9cc3cf46bc3a5dfe871a8ada19a37a4429a8e7e85e00 23
23 Key Agreement Schemes 24 Generates secret key common to both parties Benefits Same shared key created, without key exchange Both parties influence the outcome Insecure channel communication Usages WPS, SSL/TLS, SSH, VPN Algorithms Diffie-Hellman Notes Asymmetric Man-in-the-Middle attack Unique key sizes
24 Key Agreement Schemes (128 bit) Party A diffie_hellman dh_1(128); const auto& base_1 = dh_1.get_base(); const auto& prime_1 = dh_1.get_prime(); const auto& public_key_1 = dh_1.get_public_key(); cout << "Base: " << hex::encode(base_1) << endl; cout << "Prime: " << hex::encode(prime_1) << endl; cout << "Public Key: " << hex::encode(public_key_1) << endl; // Base: 03 // Prime: c5e136753c1c8b ecf3 // Public Key: 3f19880e8bf951f94c6dc dde5 25
25 Key Agreement Schemes (128 bit) Party B diffie_hellman dh_2(prime_1, base_1); const bool status_2 = dh_2.compute(public_key_1); const auto& public_key_2 = dh_2.get_public_key(); const auto& shared_key_2 = dh_2.get_shared_key(); cout << "Public Key: " << hex::encode(public_key_2) << endl; cout << "Shared Key: " << hex::encode(shared_key_2) << endl; // Public Key: 0a54116dc11c41ac6c2a3a95a9c61715 // Shared Key: 29cabdd82222c74e7dc44dea9b113a21 Party A const bool status_1 = dh_1.compute(public_key_2); const auto& shared_key_1 = dh_1.get_shared_key(); 26 cout << "Shared Key: " << hex::encode(secret_key_1) << endl; // Shared Key: 29cabdd82222c74e7dc44dea9b113a21
26 Key Agreement Schemes (2048 bit) Base 02 Prime e85d aa7988a681b914ad0d4aa1d5ba17a8be374be808dc26ed988c5b8d7e a6db54ed9a75a436f4b fa17d732d355d3835b7ec9ba131ffe9e f11a9f70a27d440ccf193d6609f98e86ce17000fdb04cdf2d74da2c1e1c5f 8b7ba0fafb5617e7e29f5509b3be2d7dadc4da9f4d9f e978eeb6b2521e5bc097c6ef859cfd736e6413b144b9e48a0 440e e06d12aa afa467ecc40ab9002db2fa9c9fee39e4c375957f45937fca6c8c9927c8a986d3ec8 9b7059fb3cd66fccfb69a94870afe6b81b190163e152f24895e ed9d818a02b3efff23812ecba5e07a3b564f2 76e5515a4fffd45bf87 27 Public Key (A) 1ae20832c2fd50afab8cb387ccdada3ae620b5f22555dde d4f05ede1d9b762bbb af6d4c5d 5f8f2cfa441660b386e77302f f786385aafaf0c55802e10890ba2da3e16df2ebf3b0dbe466fce dc0a498a8 cca2ee946dcb28517b1a7bb768175aa5cdf26c3bf1c54f92a1ee7fe06dfdb be1f76e14ab7f e033 9aa687b72f47836cde ca390c2425a92f3bea053168bf70adc325363d3ffc66a0be7aac5438dc43d ee096 a0a142292dbad376eedb960b f2c796df07df7e78b3f16961ed33ff4690d3c9cd300a3d5ac4359a8440aa3a125a61 d9aba9a20fd5e960eceb965c
27 Key Agreement Schemes (2048 bit) Public (B) 35c8abc9cac1e9ca365005b22ab98c8d1efa5656d e5de37a793ba8f8c235886fa3f5c6b6164c662b 21b18ea03b901297a6be623dc8ec5dad106b2e7cd7ab9a339187ea4142f593e414c e0bdede22d3bb ef ce5f01b4f81a15c61acd948f03f e31e668ec998ce0ef1c11e99afcf bc1358cfc41b0b742954c1c 09a539ce2d1845a735b1ad5e12359b6d271195c0fca1b3b8b7135b05857b8f9c5b66f0517c1335eeab0f6916f1848abc6c af5af417a23c531f02bde7167d268494c009d39815c27d2e8610ac021c26e6a64729c1888dad19f9b026fa752039b8b a18ce6e0285d8060b9b70c20 Shared (A, B) 980b1baeff b384f46743d31b69b830b109e28f81aca96a3c38fe8538dd64ff835b830472a266eca8f f82ede682c57b59c83640b86e0a46edd25923f7e089da9540cb73dd2db9ddde8514c782f9cd2dd5de6a08ed7cae357e1c4ff fb6ecf386f979b2bdd1c755fb6b1efa049d3612c7d51d a2cd3e788104af d4c7b4b56b2d1b6460a665458d 874c8eaee1ec57abe0f7a5335e55f41e32e1c dbb542f7d4b5481d651ca2f9d748731bf9a878b84d2ce822f68e2c6f 3a6aa712da5ed31a6beb7c4dd fe809bed9564ffc5772d9e2caebadc749dc806990d9e682f57df33ac7d739 89fedefa71d73b18b2b
28 Securing our Future I am regularly asked what the average Internet user can do to ensure his security. My first answer is usually 'Nothing; you're screwed'. Bruce Schneier
29 Demonsaw Demonsaw 1.x Buggy, Windows-only, C# Secure, Anonymous, Free, Everywhere? Demonsaw 2.0 Goals Everywhere (Unified code base: C++ 11, Boost, Crypto++) Simplify the interface Increase security Add more features Demonsaw 2.0 Features Windows, Linux, OSX, Raspberry Pi Secure chat Social Encryption Modern UI, opt-in features, command-line interface, customizable themes
30 31 Demo
31 Summary A hacker to me is someone creative who does wonderful things. Tim Berners-Lee
32 Next Steps Thank you for believing in the Right to Share The demonsaw promise 100% free, no ads, no installs, no malware, no bundled software, no logging, no tracking, no bullshit Your continued support Suggestions, bug fixes, beta testing One person can make a difference , Twitter The best is yet to come 33
33 Questions? 34 Eijah
34 References
35
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