Cryptography Fundamentals

A digital signature proves who created a message and that it hasn't been modified. Here's how signing works with RSA and ECDSA, where signatures are used in PKI, and where verification fails.

ECC provides equivalent security to RSA with dramatically smaller keys and faster operations. Here's how elliptic curves work, which curves to use, and why ECC dominates modern TLS deployments.

Key exchange lets two parties derive a shared secret over an insecure channel without transmitting the secret itself. Here's how DH and ECDHE work, why ephemeral keys provide forward secrecy, and where key exchange fails.

RSA is the most widely deployed asymmetric algorithm, used in TLS certificates, code signing, and key exchange. Here's how the math works, what key sizes to use, and why RSA is being replaced by ECC and post-quantum algorithms.

A cipher suite is the combination of algorithms negotiated during a TLS handshake: key exchange, authentication, encryption, and hashing. Here's how to read them, which to enable, and which to disable.

AES is the symmetric encryption algorithm that protects virtually all encrypted data in transit and at rest. Here's how it works, which modes to use, and where AES implementations fail in practice.

Asymmetric encryption uses a key pair — public key encrypts, private key decrypts. Here's how it enables TLS, digital signatures, and key exchange without sharing secrets.

A cryptographic hash function produces a fixed-size fingerprint from any input. Here's how hashing works, why it's irreversible, and where it's used in certificates, signatures, and integrity verification.

Understand symmetric encryption, how it works, common algorithms like AES and ChaCha20, and when to use symmetric vs asymmetric encryption in enterprise security.