Index

/dev/random, 35
/dev/urandom, 34

accounting, 12
additive inverse, 81
asymmetric cryptography, see public key cryptography
asymmetric key crypto, see public-key crypto
attacks
    brute force, see brute force attack
    frequency analysis, see frequency analysis
authentication, 12
authorisation, 12
availability, 11

base64, 585
bc, 31
brute force attack, 124
    example, 124
    monoalphabetic cipher, 128
    Python, 124

Caesar cipher, 118
    definition, 118, 121
    example, 119–121
    Python, 123
CIA, 11
cipher, 16
ciphers
    Caesar, see Caesar cipher
    monoalphabetic, see monoalphabetic cipher
    Playfair, see Playfair cipher
    polyalphabetic, see polyalphabetic cipher
ciphertext, 16
cmp
    example, 428
confidentiality, 11
congruence, 76
congruent modulo, 76
conventional crypto, see symmetric key crypto
cryptanalysis, 16
cryptography, 16
cryptology, 16
cut, 31
    example, 35

decryption, 16, 251
diff
    example, 251, 298
digital signature, 407
discrete logarithm, 94
divides, 65
divisor, 65

echo
    example, 253
encryption, 13, 16, 251
Euler’s totient, 73

Feistel network, 167
Fermat’s theorem, 89
frequency analysis, 129
    monoalphabetic, 141

gcd(), see greatest common divisor
git
    example, 41
greatest common divisor, 66

integer factorisation, 106
integrity, 11

key, 16

Linux, 30
    Ubuntu, 30
logarithm, 93

md5sum, 35
mod, 75
mode of operation, 252
modular addition, 79
modular arithmetic, 77
modular division, 86
modular exponentiation, 92
modular logarithm
    see discrete logarithm 94
modular multiplication, 83
modular subtraction, 82
modulus, 75
monoalphabetic cipher, 127
    definition, 127
    example, 127
multiplicative inverse, 85

One-Time Pad, 151
OpenSSL, 36, 37
    dgst, 407
    enc, 251
    genpkey, 402, 425
    help, 37
    list, 38
    padding, 252
    pkey, 403
    pkeyparam, 425
    pkeyutl, 407, 428
    rand, 40, 254
    smime, 407
    speed, 299
    version, 38

passwords
    salt, 252
permutation, 126, 167
plaintext, 16
Playfair cipher, 142
    definition, 142, 143
    example, 142, 143
polyalphabetic cipher, 145
    definition, 145
prime factorisation, 72
prime factors, 70
prime number, 67
primitive root, 94
public key cryptography, 367, 401
public-key crypto, 164
pycipher, 41
Python, 41

rail fence cipher, 154
random numbers
    /dev/random, 35
    /dev/urandom, 34
    $RANDOM, 34
relatively prime, 66
rows columns cipher, 155
RSA, 401

S-DES, 212
security protections, 11
sha1sum, 35
sha256sum, 35
sha512sum, 35
shared-key crypto, see symmetric key crypto
Simplified-DES, see S-DES
single-key crypto, see symmetric key crypto
SPN, 167
substitution, 167
symmetric key crypto, 164

transposition, 153

Ubuntu, see Linux

Vernam cipher, 150
Vigenère cipher, 146
    example, 147

wc
    example, 253

XOR
    Python, 150
xxd, 30
    example, 34, 40, 253, 298