Cryptography Tutorials - Herong's Tutorial Examples - v5.42, by Herong Yang
Key Schedule (Sub-Keys Generation) Algorithm
This section describes the Blowfish Key Schedule (Sub-Keys Generation) algorithm. It uses the binary representation of the fractional portion of constant Pi - 3.1415927... as initial values.
Blowfish key schedule algorithm:
Input: K: The key - 32 bits or more PI: The binary representation of the fractional portion of "pi" = 3.1415927... - 3.0 = 2/16 + 4*/16**2 + 3/16**3 + 15/16**4 + ... = 0x243f6a8885a308d313198a2e03707344... Output: P1, P2, ..., P18: 18 32-bit sub-keys S1[], S2[], S3[], S4[]: 4 S-boxes, 32-bit 256-element arrays Algorithm: (P1, P2, ..., P18, S1[], S2[], S3[], S4[]) = PI K' = (K, K, K, ...), Repeat the key to 18*32 bits long (P1, P2, ..., P18) = (P1, P2, ..., P18) XOR K' T = (0x000000, 0x000000), Setting initial clear text T = Blowfish(T), Applying Blowfish algorithm (P1, P2) = T, Updating first two sub-keys T = Blowfish(T), Applying Blowfish again (P3, P4) = T ...... T = Blowfish(T) (P17, P18) = T T = Blowfish(T) (S1[0], S1[1]) = T T = Blowfish(T) (S1[2], S1[3]) = T ...... T = Blowfish(T) (S1[254], S1[255]) = T T = Blowfish(T) (S2[0], S2[1]) = T ...... T = Blowfish(T) (S4[254], S4[255]) = T
Note that:
Table of Contents
Introduction to AES (Advanced Encryption Standard)
DES Algorithm - Illustrated with Java Programs
DES Algorithm Java Implementation
DES Algorithm - Java Implementation in JDK JCE
DES Encryption Operation Modes
PHP Implementation of DES - mcrypt
►Blowfish - 8-Byte Block Cipher
►Key Schedule (Sub-Keys Generation) Algorithm
BlowfishJ - Java Implementation by Markus Hahn
Secret Key Generation and Management
Cipher - Secret Key Encryption and Decryption
RSA Implementation using java.math.BigInteger Class
Introduction of DSA (Digital Signature Algorithm)
Java Default Implementation of DSA
Private key and Public Key Pair Generation
PKCS#8/X.509 Private/Public Encoding Standards
Cipher - Public Key Encryption and Decryption
OpenSSL Introduction and Installation
OpenSSL Generating and Managing RSA Keys
OpenSSL Generating and Signing CSR
OpenSSL Validating Certificate Path
"keytool" and "keystore" from JDK
"OpenSSL" Signing CSR Generated by "keytool"
Migrating Keys from "keystore" to "OpenSSL" Key Files
Certificate X.509 Standard and DER/PEM Formats
Migrating Keys from "OpenSSL" Key Files to "keystore"