Network Encryption Algorithms
=============================

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   AES
   DES
   3DES
   RSA
   ECC
   ChaCha20
   Blowfish
   TwoFish


Network encryption algorithms protect data confidentiality and integrity during transit and storage. These algorithms are essential for securing modern network communications.

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   * - Algorithm
     - Description
     - Use Case
   * - AES (Advanced Encryption Standard)
     - Symmetric block cipher with 128-, 192-, or 256-bit keys.  
       Fast, secure, and widely adopted across many applications.  
       *Used in VPNs, TLS, and encrypted storage.*
     - VPN encryption, HTTPS/TLS, disk encryption
   * - DES (Data Encryption Standard)
     - Older symmetric cipher using 56-bit keys.  
       Now considered insecure due to brute-force vulnerabilities.  
       *Primarily in legacy systems.*
     - Legacy system compatibility
   * - 3DES (Triple DES)
     - Applies DES encryption three times for added security.  
       More secure than DES but slower and deprecated.
     - Legacy financial systems, ATM networks
   * - RSA (Rivest–Shamir–Adleman)
     - Asymmetric encryption based on large integer factorization.  
       Used for secure key exchange and digital signatures.
     - SSL/TLS handshakes, email signing, SSH authentication
   * - ECC (Elliptic Curve Cryptography)
     - Asymmetric algorithm using elliptic curves for smaller keys and faster operations.
     - Mobile encryption, digital signatures, IoT devices
   * - ChaCha20
     - Fast stream cipher optimized for software, especially on constrained devices.
     - TLS (Google Chrome), VPNs, SSH
   * - Blowfish
     - Block cipher with variable-length key up to 448 bits.  
       Mostly replaced by AES.
     - Password hashing (bcrypt), file encryption
   * - TwoFish
     - AES finalist cipher with strong security and flexibility.
     - Disk encryption, open-source secure apps

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   .. tab-item:: AES (Advanced Encryption Standard)

      **RFC:** FIPS PUB 197

      **Main Features:**

      - Symmetric block cipher (128-bit blocks)
      - Key sizes: 128, 192, or 256 bits
      - Extremely fast and secure
      - Widely used in TLS, IPsec, WPA2/WPA3

      **Use Cases:**

      - VPN traffic encryption
      - HTTPS/TLS communication
      - Encrypted file and disk storage

      **Alternative Algorithms:**

      - ChaCha20 – Better performance on mobile devices
      - TwoFish – Flexible alternative for disk encryption

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         **Let us learn more about AES:**
         
         * :ref:`Learnings in this section <AES_step1>`

         * :ref:`Terminology <AES_step2>`

         * :ref:`Version Info <AES_step3>`

         * :ref:`AES Version&RFC Details <AES_step5>`

         * :ref:`AES Basic Setup on Ubuntu using IPv4 <AES_step19>`

         * :ref:`AES Basic Setup on Ubuntu using IPv6 <AES_step20>`

         * :ref:`AES Protocol Packet Details <AES_step6>`

         * :ref:`AES Usecases <AES_step7>`

         * :ref:`AES Basic Features <AES_step8>`

         * :ref:`AES Feature : Symmetric Key Cipher <AES_step9>` 

         * :ref:`AES Feature : Block Cipher <AES_step10>`

         * :ref:`AES Feature : Key Sizes <AES_step11>`  

         * :ref:`AES Feature : Number of Rounds <AES_step12>`  

         * :ref:`AES Feature : Substitution-Permutation Network (SPN) <AES_step13>`

         * :ref:`AES Feature : Fast and Efficient <AES_step14>`

         * :ref:`AES Feature : Strong Security <AES_step15>`   

         * :ref:`AES Feature : Widely Adopted <AES_step16>` 

         * :ref:`AES Feature : Flexible Modes of Operation <AES_step17>` 

         * :ref:`Reference links <AES_step18>`


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   .. tab-item:: DES (Data Encryption Standard)

      **RFC:** FIPS PUB 46-3

      **Main Features:**

      - 56-bit symmetric key
      - 64-bit block size
      - Vulnerable to brute-force attacks
      - Considered obsolete

      **Use Cases:**

      - Legacy systems only
      - Cryptography education and reference

      **Alternative Algorithms:**

      - AES – Modern secure replacement
      - 3DES – Transitional stronger variant

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         **Let us learn more about DES:**

         * :ref:`Learnings in this section <DES_step1>`

         * :ref:`Terminology <DES_step2>`

         * :ref:`Version Info <DES_step3>`

         * :ref:`DES Version&RFC Details <DES_step5>`

         * :ref:`DES Basic Setup on Ubuntu using IPv4 <DES_step20>`

         * :ref:`DES Basic Setup on Ubuntu using IPv6 <DES_step21>`

         * :ref:`DES Protocol Packet Details <DES_step6>`

         * :ref:`DES Usecases <DES_step7>`

         * :ref:`DES Basic Features <DES_step8>`

         * :ref:`DES Feature : Symmetric Key Cipher <DES_step9>` 

         * :ref:`DES Feature : Block Cipher <DES_step10>`

         * :ref:`DES Feature : Key Size <DES_step11>`  

         * :ref:`DES Feature : Feistel Structure <DES_step12>`  

         * :ref:`DES Feature : Initial & Final Permutations <DES_step13>`

         * :ref:`DES Feature : Subkeys Generation <DES_step14>`

         * :ref:`DES Feature : S-Boxes <DES_step15>`   

         * :ref:`DES Feature : Fast in Hardware <DES_step16>` 

         * :ref:`DES Feature : Vulnerable to Brute Force <DES_step17>`

         * :ref:`DES Feature : Superseded by AES <DES_step18>`

         * :ref:`Reference links <DES_step19>`

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   .. tab-item:: 3DES (Triple DES)

      **RFC:** NIST SP 800-67

      **Main Features:**

      - Encrypts data three times using DES
      - 112- or 168-bit key length
      - Slower than AES
      - Used mainly in legacy financial systems

      **Use Cases:**

      - ATM and banking security
      - Legacy enterprise encryption

      **Alternative Algorithms:**

      - AES – Faster and more secure
      - TwoFish – Modern alternative cipher

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         **Let us learn more about 3DES:**

         * :ref:`Learnings in this section <3DES_step1>`

         * :ref:`Terminology <3DES_step2>`

         * :ref:`Version Info <3DES_step3>`

         * :ref:`3DES Version&RFC Details <3DES_step5>`

         * :ref:`3DES Basic Setup on Ubuntu using IPv4 <3DES_step20>`

         * :ref:`3DES Basic Setup on Ubuntu using IPv6 <3DES_step21>`

         * :ref:`3DES Protocol Packet Details <3DES_step6>`

         * :ref:`3DES Usecases <3DES_step7>`

         * :ref:`3DES Basic Features <3DES_step8>`

         * :ref:`3DES Feature : Symmetric Key Cipher <3DES_step9>` 

         * :ref:`3DES Feature : Block Cipher <3DES_step10>`

         * :ref:`3DES Feature : Keying Options <3DES_step11>`  

         * :ref:`3DES Feature : Triple Encryption <3DES_step12>`  

         * :ref:`3DES Feature : Backward Compatibility <3DES_step13>`

         * :ref:`3DES Feature : Feistel Structure <3DES_step14>`

         * :ref:`3DES Feature : Stronger than DES <3DES_step15>`   

         * :ref:`3DES Feature : Slower than AES <3DES_step16>` 

         * :ref:`3DES Feature : Systems <3DES_step17>`

         * :ref:`3DES Feature : Being Phased Out <3DES_step18>`

         * :ref:`Reference links <3DES_step19>`

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   .. tab-item:: RSA (Rivest–Shamir–Adleman)

      **RFC:** RFC 8017 (PKCS #1 v2.2)

      **Main Features:**

      - Asymmetric encryption using public/private keys
      - Key sizes: 1024, 2048, 4096 bits
      - High computational overhead
      - Used for digital signatures and secure key exchange

      **Use Cases:**

      - TLS handshakes and certificates
      - Email encryption and signing
      - SSH key authentication

      **Alternative Algorithms:**

      - ECC – Faster with smaller keys
      - Diffie–Hellman – Secure key exchange

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         **Let us learn more about RSA:**

         * :ref:`Learnings in this section <RSA_step1>`

         * :ref:`Terminology <RSA_step2>`

         * :ref:`Version Info <RSA_step3>`

         * :ref:`RSA Version&RFC Details <RSA_step5>`

         * :ref:`RSA Basic Setup on Ubuntu using IPv4 <RSA_step19>`

         * :ref:`RSA Basic Setup on Ubuntu using IPv6 <RSA_step20>`

         * :ref:`RSA Protocol Packet Details <RSA_step6>`

         * :ref:`RSA Usecases <RSA_step7>`

         * :ref:`RSA Basic Features <RSA_step8>`

         * :ref:`RSA Feature : Asymmetric Key Algorithm <RSA_step9>` 

         * :ref:`RSA Feature : Key Pair Generation <RSA_step10>`

         * :ref:`RSA Feature : Public Key Distributuion <RSA_step11>`  

         * :ref:`RSA Feature : Digital Signatures <RSA_step12>`  

         * :ref:`RSA Feature : Encryption & Decryption <RSA_step13>`

         * :ref:`RSA Feature : Key sizes <RSA_step14>`

         * :ref:`RSA Feature : Slower than Symmetric Ciphers <RSA_step15>`   

         * :ref:`RSA Feature : Widely Used in Protocols <RSA_step16>` 

         * :ref:`RSA Feature : Standardized <RSA_step17>` 

         * :ref:`Reference links <RSA_step18>`


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   .. tab-item:: ECC (Elliptic Curve Cryptography)

      **RFC:** RFC 7748, RFC 4492

      **Main Features:**

      - Asymmetric cryptography using elliptic curves
      - Smaller key sizes with equivalent security to RSA
      - Efficient CPU and memory usage

      **Use Cases:**

      - Mobile and IoT device encryption
      - VPN encryption (e.g., Curve25519)
      - Digital signatures

      **Alternative Algorithms:**

      - RSA – More established but heavier
      - EdDSA – ECC-based signature scheme

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         **Let us learn more about ECC:**

         * :ref:`Learnings in this section <ECC_step1>`

         * :ref:`Terminology <ECC_step2>`

         * :ref:`Version Info <ECC_step3>`

         * :ref:`ECC Version&RFC Details <ECC_step5>`

         * :ref:`ECC Basic Setup on Ubuntu using IPv4 <ECC_step20>`

         * :ref:`ECC Basic Setup on Ubuntu using IPv6 <ECC_step21>`

         * :ref:`ECC Protocol Packet Details <ECC_step6>`

         * :ref:`ECC Usecases <ECC_step7>`

         * :ref:`ECC Basic Features <ECC_step8>`

         * :ref:`ECC Feature : Asymmetric Key Algorithm <ECC_step9>` 

         * :ref:`ECC Feature : Elliptic Curve Mathematics <ECC_step10>`

         * :ref:`ECC Feature : Smaller Key Sizes <ECC_step11>`  

         * :ref:`ECC Feature : Efficient Computation <ECC_step12>`  

         * :ref:`ECC Feature : Digital Signatures (ECDSA) <ECC_step13>`

         * :ref:`ECC Feature : Key Exchange (ECDH) <ECC_step14>`

         * :ref:`ECC Feature : Low Bandwidth & Storage <ECC_step15>`   

         * :ref:`ECC Feature : Ideal for Mobile & IoT <ECC_step16>` 

         * :ref:`ECC Feature : Widely Standardized <ECC_step17>`

         * :ref:`ECC Feature : Used in Modern Protocols <ECC_step18>`

         * :ref:`Reference links <ECC_step19>`


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   .. tab-item:: ChaCha20

      **RFC:** RFC 8439

      **Main Features:**

      - Stream cipher optimized for software performance
      - 256-bit key with nonce-based encryption
      - Resistant to timing attacks

      **Use Cases:**

      - TLS in Google Chrome and Android
      - VPNs like WireGuard
      - SSH encryption

      **Alternative Algorithms:**

      - AES – Better hardware support
      - Salsa20 – Predecessor stream cipher

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         **Let us learn more about ChaCha20:**

         * :ref:`Learnings in this section <ChaCha20_step1>`

         * :ref:`Terminology <ChaCha20_step2>`

         * :ref:`Version Info <ChaCha20_step3>`

         * :ref:`ChaCha20 Version&RFC Details <ChaCha20_step5>`

         * :ref:`ChaCha20 Basic Setup on Ubuntu using IPv4 <ChaCha20_step20>`

         * :ref:`ChaCha20 Basic Setup on Ubuntu using IPv6 <ChaCha20_step21>`

         * :ref:`ChaCha20 Protocol Packet Details <ChaCha20_step6>`

         * :ref:`ChaCha20 Usecases <ChaCha20_step7>`

         * :ref:`ChaCha20 Basic Features <ChaCha20_step8>`

         * :ref:`ChaCha20 Feature : Symmetric Stream Cipher <ChaCha20_step9>` 

         * :ref:`ChaCha20 Feature : 256-bit Key <ChaCha20_step10>`

         * :ref:`ChaCha20 Feature : 96-bit Nonce <ChaCha20_step11>`  

         * :ref:`ChaCha20 Feature : 20 rounds of Mixing <ChaCha20_step12>`  

         * :ref:`ChaCha20 Feature : No Padding Required <ChaCha20_step13>`

         * :ref:`ChaCha20 Feature : Constant-Time Execution <ChaCha20_step14>`

         * :ref:`ChaCha20 Feature : High Performance in Software <ChaCha20_step15>`   

         * :ref:`ChaCha20 Feature : Design <ChaCha20_step16>` 

         * :ref:`ChaCha20 Feature : AEAD Support (with poly1305) <ChaCha20_step17>`

         * :ref:`ChaCha20 Feature : Cross-Platform Compatibility <ChaCha20_step18>`

         * :ref:`Reference links <ChaCha20_step19>`

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   .. tab-item:: Blowfish

      **RFC:** Not standardized by RFC (Published by Schneier)

      **Main Features:**

      - 64-bit block cipher
      - Variable key length up to 448 bits
      - Fast in software but limited block size

      **Use Cases:**

      - Password hashing (bcrypt)
      - Embedded system encryption

      **Alternative Algorithms:**

      - AES – Modern replacement
      - TwoFish – Larger blocks and stronger design

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         **Let us learn more about Blowfish:**

         * :ref:`Learnings in this section <Blowfish_step1>`

         * :ref:`Terminology <Blowfish_step2>`

         * :ref:`Version Info <Blowfish_step3>`

         * :ref:`Blowfish Version&RFC Details <Blowfish_step5>`

         * :ref:`Blowfish Basic Setup on Ubuntu using IPv4 <Blowfish_step20>`

         * :ref:`Blowfish Basic Setup on Ubuntu using IPv6 <Blowfish_step21>`

         * :ref:`Blowfish Protocol Packet Details <Blowfish_step6>`

         * :ref:`Blowfish Usecases <Blowfish_step7>`

         * :ref:`Blowfish Basic Features <Blowfish_step8>`

         * :ref:`Blowfish Feature : Symmetric Block Cipher <Blowfish_step9>` 

         * :ref:`Blowfish Feature : Variable Key Length <Blowfish_step10>`

         * :ref:`Blowfish Feature : 16-Round Feistel Network <Blowfish_step11>`  

         * :ref:`Blowfish Feature : Key-Dependent S-boxes <Blowfish_step12>`  

         * :ref:`Blowfish Feature : Fast in Software <Blowfish_step13>`

         * :ref:`Blowfish Feature : No Licensing Required <Blowfish_step14>`

         * :ref:`Blowfish Feature : Security Design <Blowfish_step15>`   

         * :ref:`Blowfish Feature : Lightweight Implementation <Blowfish_step16>` 

         * :ref:`Blowfish Feature : Legacy Compatibility <Blowfish_step17>`

         * :ref:`Blowfish Feature : Basis for bcrypt <Blowfish_step18>`

         * :ref:`Reference links <Blowfish_step19>`


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   .. tab-item:: TwoFish

      **RFC:** AES competition finalist (no formal RFC)

      **Main Features:**

      - 128-bit block cipher
      - Variable key lengths up to 256 bits
      - Strong and efficient design

      **Use Cases:**

      - Disk encryption (e.g., VeraCrypt)
      - Open-source cryptographic apps

      **Alternative Algorithms:**

      - AES – Widely used standard
      - Serpent – Another AES finalist

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         **Let us learn more about TwoFish:**

         * :ref:`Learnings in this section <TwoFish_step1>`

         * :ref:`Terminology <TwoFish_step2>`

         * :ref:`Version Info <TwoFish_step3>`

         * :ref:`TwoFish Version&RFC Details <TwoFish_step5>`

         * :ref:`TwoFish Basic Setup on Ubuntu using IPv4 <TwoFish_step19>`

         * :ref:`TwoFish Basic Setup on Ubuntu using IPv6 <TwoFish_step20>`

         * :ref:`TwoFish Protocol Packet Details <TwoFish_step6>`

         * :ref:`TwoFish Usecases <TwoFish_step7>`

         * :ref:`TwoFish Basic Features <TwoFish_step8>`

         * :ref:`TwoFish Feature : Block Cipher <TwoFish_step9>` 

         * :ref:`TwoFish Feature : Variable Key Length <TwoFish_step10>`

         * :ref:`TwoFish Feature : Feistel Network <TwoFish_step11>`  

         * :ref:`TwoFish Feature : Key-Dependent S-boxes <TwoFish_step12>`  

         * :ref:`TwoFish Feature : MDS Matrix <TwoFish_step13>`

         * :ref:`TwoFish Feature : Whitening steps <TwoFish_step14>`

         * :ref:`TwoFish Feature : High Performance <TwoFish_step15>`   

         * :ref:`TwoFish Feature : Unpatented and Open <TwoFish_step16>` 

         * :ref:`TwoFish Feature : AES Finalist <TwoFish_step17>` 

         * :ref:`Reference links <TwoFish_step18>`

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