Crypto Talk: Difference between revisions
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Adamcolton (talk | contribs) Created page with "* Goal of Talk ** What different primates are and what they are for ** Not for building crypto - don't do that * Purpose of Crypto ** Privacy ** Validation ** Authenticity * H..." |
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== TSC == | |||
* Goal of Talk | * Goal of Talk | ||
** What different | ** What different primitives are and what they are for | ||
** Not for building crypto - don't do that | ** Not for building crypto - don't do that | ||
* Purpose of Crypto | * Purpose of Crypto | ||
| Line 21: | Line 22: | ||
** What is a hash | ** What is a hash | ||
** MAC | ** MAC | ||
** Advantage on non-crypto hash | |||
** Pigeon hole and collision resistance | ** Pigeon hole and collision resistance | ||
** Block Chain and Merkle Tree | |||
** Password hashing | |||
* Block Ciphers | * Block Ciphers | ||
** AES | ** AES | ||
** CBC vs CTR | ** CBC vs CTR | ||
** Nonce | ** Nonce | ||
* | * Stream Ciphers | ||
** | ** Simpler to understand, harder to implement | ||
* Comparison | |||
** Mostly, don't worry | |||
** Block ciphers are easier to design | |||
** Stream ciphers are faster | |||
* Asymmetric | * Asymmetric | ||
** Diffe-Hellman - won't cover, but they got there first | ** Diffe-Hellman - won't cover, but they got there first | ||
| Line 34: | Line 41: | ||
** RSA | ** RSA | ||
** Elliptic | ** Elliptic | ||
** Encryption and signature | |||
* Future | |||
** Quantum computing | |||
** Homomorphic cryptography | |||
== Understanding Blocks == | |||
* Alice or (Alice and Bob) have a 256bit key - 100 digit number | |||
* Not covering key exchange (maybe later) | |||
* Encryption is many things | |||
** Already discussed encryption and key exchange | |||
** Also authentication - message is unchanged and from source | |||
* Hash - like fingerprint | |||
* Block hash using exponents | |||
** r ^ n % p = h | |||
** p : prime | |||
** r : primitive root | |||
** n : input | |||
** h : hash | |||
** algorithm to do this quickly | |||
** given r, p and h, cannot be reversed (discrete log problem) | |||
* Chaining block hash with key for HMAC | |||
** nonce | |||
** XOR | |||
** h[n] = hash(m[n] XOR h[n-1]) | |||
* XOR using hash as PRNG | |||
* Problem: Anything that can authenticate can encrypt | |||
Latest revision as of 16:47, 30 April 2020
TSC
- Goal of Talk
- What different primitives are and what they are for
- Not for building crypto - don't do that
- Purpose of Crypto
- Privacy
- Validation
- Authenticity
- History
- Substitution cipher → freq analysis
- Vigener Cipher → freq analysis again
- Symmetric Cipher
- Claude Shannon and perfect security
- XOR OTP example
- Problems with OTP/sym.
- key must be exchanged
- PRG
- Still must be OTP
- Repeat attack
- Substitution attack
- key must be exchanged
- Hashing
- What is a hash
- MAC
- Advantage on non-crypto hash
- Pigeon hole and collision resistance
- Block Chain and Merkle Tree
- Password hashing
- Block Ciphers
- AES
- CBC vs CTR
- Nonce
- Stream Ciphers
- Simpler to understand, harder to implement
- Comparison
- Mostly, don't worry
- Block ciphers are easier to design
- Stream ciphers are faster
- Asymmetric
- Diffe-Hellman - won't cover, but they got there first
- Key exchange
- RSA
- Elliptic
- Encryption and signature
- Future
- Quantum computing
- Homomorphic cryptography
Understanding Blocks
- Alice or (Alice and Bob) have a 256bit key - 100 digit number
- Not covering key exchange (maybe later)
- Encryption is many things
- Already discussed encryption and key exchange
- Also authentication - message is unchanged and from source
- Hash - like fingerprint
- Block hash using exponents
- r ^ n % p = h
- p : prime
- r : primitive root
- n : input
- h : hash
- algorithm to do this quickly
- given r, p and h, cannot be reversed (discrete log problem)
- Chaining block hash with key for HMAC
- nonce
- XOR
- h[n] = hash(m[n] XOR h[n-1])
- XOR using hash as PRNG
- Problem: Anything that can authenticate can encrypt