332 INDEX

relatively prime, 29, 90

Room 40, 8

rotors, 64

RSA, 13, 214, 216

problem, 230

theorem, 229

running key cipher, 120

S-box, 160

Secure Hash Algorithm (SHA)

SHA-1, 225

seed, 140

self-loops, 204

sifr, 4

signature, 21

signatures, 220

simple, 204

sphere packings, 260

Stager cipher, 7

steganography, 13, 20, 269

stego-function, 270

stego-object, 270

still images, 273

Strassen algorithm, 208, 233

stream ciphers, 138

substitution alphabet ciphers, 22

Sudoku puzzles, 275

symmetric ciphers, 171

text extraction, 285

totient function, 215, 236, 305

ToyHash, 222

transmit, 21

transparencies, 283

transposition, 48

trap-door functions, 294

triangle inequality, 253

Turing, Alan, 70

twin primes, 197

Ultra, 11, 52

unit, 29, 192

Universal Product Code (UPC)

symbols, 257

valid encryption scheme, 21, 22

Verhoeff, Jacobus, 259

vertical line shift coding, 272

vertices, 173

Vigen` ere cipher, 34

Kasiski test, 102

keystream, 34

winnowing, 277

XOR, 137

Zimmerman telegram, 8