Cryptopals

My solutions to the problems at https://cryptopals.com/

Solves

• Set 1
  • Convert hex to base64
  • Fixed XOR
  • Single-byte XOR cipher
  • Detect single-character XOR
  • Implement repeating-key XOR
  • Break repeating-key XOR
  • AES in ECB mode
  • Detect AES in ECB mode

• Set 2
  • Implement PKCS#7 padding
  • Implement CBC mode
  • An ECB/CBC detection oracle
  • Byte-at-a-time ECB decryption (Simple)
  • ECB cut-and-paste
  • Byte-at-a-time ECB decryption (Harder)
  • PKCS#7 padding validation
  • CBC bitflipping attacks

• Set 3
  • The CBC padding oracle
  • Implement CTR, the stream cipher mode
  • Break fixed-nonce CTR mode using substitutions
  • Break fixed-nonce CTR statistically
  • Implement the MT19937 Mersenne Twister RNG
  • Crack an MT19937 seed
  • Clone an MT19937 RNG from its output
  • Create the MT19937 stream cipher and break it

• Set 4
  • Break "random access read/write" AES CTR
  • CTR bitflipping
  • Recover the key from CBC with IV=Key
  • Implement a SHA-1 keyed MAC
  • Break a SHA-1 keyed MAC using length extension
  • Break an MD4 keyed MAC using length extension
  • Implement and break HMAC-SHA1 with an artificial timing leak
  • Break HMAC-SHA1 with a slightly less artificial timing leak

• Set 5
  • Implement Diffie-Hellman
  • Implement a MITM key-fixing attack on Diffie-Hellman with parameter injection
  • Implement DH with negotiated groups, and break with malicious "g" parameters
  • Implement Secure Remote Password (SRP)
  • Break SRP with a zero key
  • Offline dictionary attack on simplified SRP
  • Implement RSA
  • Implement an E=3 RSA Broadcast attack

• Set 6
  • Implement unpadded message recovery oracle
  • Bleichenbacher's e=3 RSA Attack
  • DSA key recovery from nonce
  • DSA nonce recovery from repeated nonce
  • DSA parameter tampering
  • RSA parity oracle
  • Bleichenbacher's PKCS 1.5 Padding Oracle (Simple Case)
  • Bleichenbacher's PKCS 1.5 Padding Oracle (Complete Case)

• Set 7
  • CBC-MAC Message Forgery
  • Hashing with CBC-MAC
  • Compression Ratio Side-Channel Attacks
  • Iterated Hash Function Multicollisions
  • Kelsey and Schneier's Expandable Messages
  • Kelsey and Kohno's Nostradamus Attack
  • MD4 Collisions
  • RC4 Single-Byte Biases

• Set 8
  • Diffie-Hellman Revisited: Small Subgroup Confinement
  • Pollard's Method for Catching Kangaroos
  • Elliptic Curve Diffie-Hellman and Invalid-Curve Attacks
  • Single-Coordinate Ladders and Insecure Twists
  • Duplicate-Signature Key Selection in ECDSA (and RSA)
  • Key-Recovery Attacks on ECDSA with Biased Nonces
  • Key-Recovery Attacks on GCM with Repeated Nonces
  • Key-Recovery Attacks on GCM with a Truncated MAC