Intro to Cryptography (C839) Western Governors
University Study Guide Latest Update.
, Symmetric Ciphers
Name Authors Key Size(bits) Block Size(bits) Rounds Algorithm Notes
128 10 (128) Substitution-Permutation,
AES 192 128 12 (192) Rijyndael Cipher
256 14 (256)
Ross Anderson, 128
SERPENT Eli Biham, 192 128 32 Substitution-Permutation
Lars Knudsen 256
Bruce Schneider,
TWOFISH Neil Ferguson Up to 256 128 16 Feistel Designed to replace DES
40-bit minimum key size recommended
SSL, Web, WiFi
RC4 1-2048 STREAM 1 RFC
32
RC5 1-2048 64 Up to 255 RC6 is a faster version of RC5
RC6 128
IDEA James Massey, 128 64 8 Lai-Massey Scheme
Xuejia Lai
TEA David Wheeler, 128 64 64 Feistel
Roger Needham
Vincent Rijimen,
SHARK Joan Daemen, 128 64 6
Erick De Win
CAST-128 40-128 64 12(<80) PGP 8-bit rounds
CAST-256 16(>80)
BLOWFISH Bruce Schneider 32-448 64 16 Feistel BCrypt, CrashPlan, Cryptodisk, DriveCrypt
DES 56 64 16 Feistel
3DES 56 64 16 Feistel Runs DES 3 times
SKIPJACK 80 64 32 Unbalanced Feistel Designed by NSA for Clipper Chip
RCA 1-256 STREAM Up to 255
FISH STREAM Lagged Fibonacci PRNG,
Data XOR’d with key
PIKE STREAM FISH improvement to address plaintext
vulnerabilities,
most common stream cipher used
, Asymmetric Ciphers
Name Authors Description Notes
RSA Ron Rivest, Leverages prime number characteristics, Most popular,
Adi Shamir, 1024-4096 key bit size, provides authentication and encryption,
Leonard Aldeman 1 round authentication through digital signatures
ECC Leverages discrete logarithm characteristics Provides authentication and encryption,
faster than RSA,
uses less resources than RSA (like cellphones),
authentication through digital signatures
El Gamal Used in recent versions of PGP Extension of Diffie-Hellman,
similar level of protection as RSA & ECC,
usually the slowest
DSA Federal Information Processing Standard for digital
signatures (FIPS186)
Diffie-Hellman No authentication and vulnerable to MITM attacks
University Study Guide Latest Update.
, Symmetric Ciphers
Name Authors Key Size(bits) Block Size(bits) Rounds Algorithm Notes
128 10 (128) Substitution-Permutation,
AES 192 128 12 (192) Rijyndael Cipher
256 14 (256)
Ross Anderson, 128
SERPENT Eli Biham, 192 128 32 Substitution-Permutation
Lars Knudsen 256
Bruce Schneider,
TWOFISH Neil Ferguson Up to 256 128 16 Feistel Designed to replace DES
40-bit minimum key size recommended
SSL, Web, WiFi
RC4 1-2048 STREAM 1 RFC
32
RC5 1-2048 64 Up to 255 RC6 is a faster version of RC5
RC6 128
IDEA James Massey, 128 64 8 Lai-Massey Scheme
Xuejia Lai
TEA David Wheeler, 128 64 64 Feistel
Roger Needham
Vincent Rijimen,
SHARK Joan Daemen, 128 64 6
Erick De Win
CAST-128 40-128 64 12(<80) PGP 8-bit rounds
CAST-256 16(>80)
BLOWFISH Bruce Schneider 32-448 64 16 Feistel BCrypt, CrashPlan, Cryptodisk, DriveCrypt
DES 56 64 16 Feistel
3DES 56 64 16 Feistel Runs DES 3 times
SKIPJACK 80 64 32 Unbalanced Feistel Designed by NSA for Clipper Chip
RCA 1-256 STREAM Up to 255
FISH STREAM Lagged Fibonacci PRNG,
Data XOR’d with key
PIKE STREAM FISH improvement to address plaintext
vulnerabilities,
most common stream cipher used
, Asymmetric Ciphers
Name Authors Description Notes
RSA Ron Rivest, Leverages prime number characteristics, Most popular,
Adi Shamir, 1024-4096 key bit size, provides authentication and encryption,
Leonard Aldeman 1 round authentication through digital signatures
ECC Leverages discrete logarithm characteristics Provides authentication and encryption,
faster than RSA,
uses less resources than RSA (like cellphones),
authentication through digital signatures
El Gamal Used in recent versions of PGP Extension of Diffie-Hellman,
similar level of protection as RSA & ECC,
usually the slowest
DSA Federal Information Processing Standard for digital
signatures (FIPS186)
Diffie-Hellman No authentication and vulnerable to MITM attacks
