10 important concepts in cryptography every software engineer should know

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Cryptographic techniques are methods and processes used in the field of cryptography to secure information and communications by converting data into a form that is unintelligible to unauthorized individuals. These techniques are crucial for ensuring data confidentiality, integrity, authentication, and non-repudiation. Here are some common cryptographic techniques:

1. Encryption: Encryption is the process of converting plaintext (human-readable data) into ciphertext (unreadable data) using an encryption algorithm and a cryptographic key. Only those with the appropriate decryption key can revert the ciphertext back to plaintext. There are various encryption algorithms, including symmetric key encryption (same key for encryption and decryption) and asymmetric key encryption (different keys for encryption and decryption).
2. Hash functions: Hash functions are one-way mathematical functions that convert an input (or message) into a fixed-length string of characters, which is typically a hexadecimal number. Hashes are used to verify data integrity because even a small change in the input results in a significantly different hash value.
3. Digital signatures: Digital signatures use asymmetric encryption to verify the authenticity and integrity of a message or document. They involve using a private key to create a unique signature that can be verified by anyone who has access to the corresponding public key.
4. Public Key Infrastructure (PKI): PKI is a framework that manages digital keys and certificates, ensuring secure communication. It includes the generation, distribution, and revocation of digital certificates that are used in encryption and digital signature processes.
5. Key exchange protocols: Key exchange protocols are used to securely exchange cryptographic keys between two parties, especially in situations where they haven’t previously shared keys. Examples include the Diffie-Hellman key exchange and the RSA key exchange.
6. Steganography: Steganography is the practice of hiding messages or data within other seemingly innocuous data (e.g., hiding text within an image). It’s a way to achieve covert communication.
7. Block ciphers and stream ciphers: These are specific types of symmetric key encryption techniques used to encrypt data in blocks or streams, respectively.
8. Secure hash algorithms: These are cryptographic hash functions designed to be resistant to various attacks. Examples include SHA-256 and SHA-3.
9. Message Authentication Codes (MACs): MACs are used to ensure data integrity and authenticity. They involve hashing a message with a secret key to create a unique code that can be verified by the recipient.
10. Secure Sockets Layer (SSL) / Transport Layer Security (TLS): These are cryptographic protocols used to secure internet communications, particularly in web browsers. They ensure secure data exchange between a client and a server.

Cryptographic techniques are a fundamental part of modern information security, and they are used in various applications, including secure communication, digital signatures, secure storage, and more.