The cryptography the discipline of ensuring the privacy, authenticity and integrity of information.
Main terms#
| The term | The definition |
|---|---|
| Encryption | Change the original text to encrypted (keywise) |
| Decoding | The reverse transformation |
| The cryptographic algorithms | Functions for encrypting/deciphering |
| The keys . | Private data of the algorithms (symmetric / asymmetry) |
| Hashing | Changing information to a static value, It 's irreversible . |
| Authenticate | Verify the authenticity of the device/user |
The Principles#
- Integrity information is not damaged when transmitted;
- Authenticate verifying the identities of the parties;
- Privacy policy protection from leakage;
- - It 's irrevocable . the sender cannot contest the shipment (via the E.C.P.).
The evolution#
| The Age | The method | Example |
|---|---|---|
| Ancient Egypt / Rome | It 's a monolithic cipher . | The Code of Caesar |
| The Middle Ages | It 's a polyalphabetic cipher . | The Vigenère cipher . |
| 20th century | Classical cryptography | Enigma (A. Shebrius, 1918) |
| The modern | Asymmetry + symmetry and hash | RSA, AES, ECC |
Types of modern cryptography#
Symmetrical (with secret key)
- One key . for encryption and decryption;
- Fast and efficient . for big data;
- The problem: the safe transfer of the key;
- The algorithms: AES, DES, 3DES, RC4.
Asymmetric (with public key)
- Two keys: public + private;
- The public cipher → the private cipher (and vice versa);
- The advantage: No need to hand over the key in advance;
- The algorithms: RSA, ECC, DSA.
Hybrid encryption
Developed I 'm going to go with Nikolai Durov . And the team . Telegram.
The idea:
- The sender creates symmetrical key;
- Encrypting it . the recipient 's public key . (asymmetrically);
- Encrypted data with a symmetric key;
- Sends together;
- The recipient . decrypts the symmetric key Your private life;
- Decoding the data.
Why ? It combines Strengths both methods secure key exchange + fast data processing.
Cryptography in the TON blockchain#
- Verify the transaction through encryption of each element;
- Digital signatures confirm the authenticity;
- Smart contracts are cryptographically protected;
- Cryptographic keys for authentication and access control;
- The modern algorithms RSA + AES for storage and transfer;
- The hash functions for the uniqueness of the records;
- Asymmetry to exchange without revealing the keys.