Table of Contents
- Types of Cryptography
- Key Exchange
- Digital Signatures
- Digital Certificates and Certificate Revocation (OCSP and CRL)
- Perfect Forward Secrecy
- Cryptology is the scientific study of Cryptography and Cryptanalysis.
- Cryptography is the practice and study of techniques for secure communication in the presence of third parties called adversaries.
- Cryptanalysis is used to breach cryptographic security systems and gain access to the contents of encrypted messages, even if the cryptographic key is unknown.
- 7 Cryptography Concepts EVERY Developer Should Know
- Security Pitfalls in Cryptography
- Why Cryptography Is Harder Than It Looks
Types of Cryptography
- Feistel Cipher
- Modes of Operation
- EXTRA BITS: Feistel Modes of Operation Code
- Securing Stream Ciphers (HMAC)
- AES: Advanced Encryption Standard
- Block size: 128 bits
- Key size: 128, 192 or 256 bits
- No. of rounds: 10, 12 and 14 rounds for 128, 192 and 256 bits key size respectively)
- SP Networks
- Rinjdael algorithm (the base of AES)
- AES Explained
- 128 Bit or 256 Bit Encryption?
- In depth working of AES (Hindi)
DES, 2DES, 3DES
- DES: Data Encryption Standard
- Block size: 64 bits
- Key size: 56 bits (64 bits in reality)
- The 64 bit key is made of eight chunks of eight bits each. The eighth bit in each chunk is a parity bit (and is thus discarded). So, the actual key length is 64 - 8 = 56.
- No. of rounds: 16
- Block size: 64 bits (Twofish has a block size of 128 bits.)
- Key size: 32 to 448 bits (The default is 128 bits.)
- No. of rounds: 16
- Blowfish Explained
- RC: Rivest/Ron’s Cipher
- Block size: 32, 64 or 128 bits
- Key size: 0 to 2040 bits
- No. of rounds: 0 to 255
- Key exchange algorithm
- End to End Encryption (E2EE)
- Secret Key Exchange (Diffie-Hellman)
- Diffie-Hellman - the Mathematics bit
- Key Exchange Problems (includes explanation on RSA)
- Elliptic Curves
- Elliptic Curve Back Door
- ‘Ephemeral’ means ‘something that is short lasting’.
- ECDH = Elliptic Curve Diffie-Hellman
- ECDH in SSH
- Perfect Forward Secrecy (FS or PFS)
- Secure Hashing Algorithm
- SHA1 Problems
- Help in establishing message integrity, i.e., proving that a particular person/origin sent the data.
- Message Authentication Codes (MACs) are symmetric key protocols, while Digital Signatures are asymmetric/public key protocols.
- What are Digital Signatures?
- Digital Signatures: What They Are & How They Work
- Digital Signatures
Digital Certificates and Certificate Revocation (OCSP and CRL)
- SSL/TLS Certificates
- Compressing Certificates in TLS
- Certificate Revocation Techniques (CRL, OCSP, OCSP Stapling)
- Shared vs Private SSL/TLS Certificates
- The SSL Certificate Issuer Field is a Lie (Credits)
- No More Extended Validation Certificate Overhead from Chrome 106
- Revocation checking and Google Chrome CRLSet
- Revocation Doesn’t Work
- The Impact of SSL Certificate Revocation on Web Performance
- A no-bull technical guide to EV HTTPS
- PKI information and X.509 certificate extensions
- PGP: Pretty Good Privacy
- Standard for PGP software
- GPG/GnuPG: GNU Privacy Guard
- Tool to use PGP
- GNU: GNU’s Not Unix
- Authentication (using the Web of Trust - importing the receiver’s public key into the sender’s key ring)
- Confidentiality (using a combo of symmetric/conventional and asymmetric key cryptography)
- Used for signing, encrypting and decrypting e-mails, files, directories, disks, etc.
- It uses the decentralized ‘Web of Trust’ to verify the identity of users. (Key rings and graphs)
- Intro to PGP
- PGP and GPG difference
- PGP and the Web of Trust
- A Pretty Good Introduction to Pretty Good Privacy
- End-to-End Encryption in the Browser Impossible?
- OpenPGP, PGP, and GPG: What is the Difference?
- Security basics with GPG, OpenSSH, OpenSSL and Keybase
- Creating the Perfect GPG Keypair
- Does OpenPGP key expiration add to security?
- Very good answer for understanding expiry date shenanigans of subkeys and the secret (private) key, and about the revocation certificate.
- How To Use GPG to Encrypt and Sign Messages
- Digitally Signing and Encrypting Messages
- Guidelines for strong passwords
- Why should one not use the same asymmetric key for encryption as they do for signing?
- Exercise: Sending an Encrypted and Signed e-mail
Perfect Forward Secrecy
- PFS or FS: Perfect Forward Secrecy
- Wikipedia: Perfect Forward Secrecy
- Perfect Forward Secrecy (PFS) in TLS
- The Heartbleed Bug
- The Logjam TLS attack: Imperfect Forward Secrecy: How Diffie-Hellman Fails in Practice (weakdh.org)
- More about TLS