Cryptography

cat-cryptography

Cryptography protects data from unauthorized access, ensuring confidentiality, integrity, authenticity, and non-repudiation. Cryptography is used to secure emails, messages, and data transfers to protect them from eavesdropping. Data Integrity ensures that data has not been tampered with. Authentication means verifying the identity of users and devices.

This section covers

  • Encryption: The process of converting plaintext into ciphertext using an algorithm and a key. Only someone with the correct key can decrypt the ciphertext back into plaintext.
  • Hashing: A method of transforming data into a fixed-size value, which is unique to the original data. Hashes are used for verifying data integrity.
  • Digital Signatures: A cryptographic technique that uses asymmetric keys to verify the authenticity and integrity of a message or document.

It covers both Symmetric Cryptography and Asymmetric Cryptography. The former uses the same key for both encryption and decryption. It's fast and efficient but requires secure key distribution. The latter uses a pair of keys (public and private). The public key is shared openly, while the private key is kept secret. This method enhances security but is slower than symmetric cryptography.

Encryption

Transforming plaintext into ciphertext for confidentiality.

  • Types: Symmetric (shared key) vs. Asymmetric (key pair).
  • Algorithms: AES, RSA.
  • Purpose: Confidentiality.
RecipeCratesCategories
Use the RSA Algorithmrsacat-cryptography

AEAD (Authenticated Encryption with Associated Data)

Encryption scheme providing both confidentiality and authentication.

  • Associated Data: Additional data bound to the ciphertext but not encrypted.
  • Algorithms: AES-GCM, ChaCha20-Poly1305.
  • Purpose: Confidentiality and authentication.
RecipeCratesCategories
aes-gcm-sivaes-gcm-siv aes-gcmcat-cryptography
aes-gcmaes-gcmcat-cryptography
ChaCha20Poly1305chacha20poly1305cat-cryptography

Hashing

One-way function producing a fixed-size "digest." Hashing is used in digital signatures, HMACs, and password hashing.

  • Properties: Deterministic, collision-resistant, preimage-resistant.
  • Algorithms: SHA-256, BLAKE3.
  • Purpose: Data integrity.
RecipeCratesCategories
Calculate the SHA-256 Digest of a Filering data-encodingcat-cryptography
sha2sha2cat-cryptography
sha1sha1cat-cryptography
md-5md-5cat-cryptography
blake3blake3cat-cryptography

Password Hashing

One-way hashing specifically to protect passwords.

  • Goals: Resistance to brute-force, rainbow table attacks.
  • Algorithms: bcrypt, Argon2, scrypt; salting (adding a unique random value before hashing).
  • Purpose: Password protection.
RecipeCratesCategories
Hash a Password, then Verify a Password Against the Hashargon2cat-cryptography
scryptscryptcat-cryptography
bcryptbcryptcat-cryptography
Salt and Hash a Password with PBKDF2ring data-encodingcat-cryptography

HMAC (Hash-based Message Authentication Code)

A Message Authentication Code (MAC) is a cryptographic checksum using a shared secret key. HMAC (Hash-based MAC) uses a hash function with a secret key.

  • Purpose: Integrity and authentication (but not non-repudiation).
RecipeCratesCategories
Sign and Verify a Message with a HMAC Digestringcat-cryptography

Digital Signatures

Cryptographic mechanism for authentication, integrity, and non-repudiation. Digital signatures are used to sign certificates and other documents.

  • Process: Signing with private key, verifying with public key.
  • Algorithms: RSA, ECDSA, Ed25519.
  • Purpose: Authentication, message integrity, non-repudiation.
RecipeCratesCategories
ed25519ed25519-websitecat-cryptography
ed25519-daleked25519-dalek-websitecat-cryptography
ecdsaecdsacat-cryptography
dsadsacat-cryptography

Digital Certificates (X.509)

Digital documents binding a public key to an identity.

  • Components: Subject, issuer, public key, validity period, signature.
  • Certificate Authorities (CAs): Trusted third parties.
  • Purpose: Identity verification.
RecipeCratesCategories
DERdercat-cryptography
pem-rfc7468pem-rfc7468cat-cryptography
pkcs8pkcs8cat-cryptography
x509-certx509-certcat-cryptography

TLS (Transport Layer Security)

Cryptographic protocol for secure communication over a network.

  • Handshake: Establishing a secure connection.
  • Encryption: TLS uses encryption (often AEAD) to protect data in transit.
  • Authentication: Verifying server (and optionally client) identity.
  • Certificates: Used for authentication.
  • Purpose: Secure communication.
RecipeCratesCategories
rustlsrustlscat-cryptography
native-tlsnative-tlscat-cryptography

Cryptographic Utilities

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subtlesubtlecat-cryptography
zeroizezeroizecat-cryptography