Add prng, keccak-256

docs/cryptography/cryptonight.md

@@ -0,0 +1,5 @@
+# CryptoNight Proof of Work
+
+Possibly the most controversial aspect of Monero (and other CryptoNote coins) is the CryptoNight Proof of Work,
+composed of 7 functions. Fortunately, the difficulty would auto-adjust should any major PoW "shortcuts" be discovered.
+Still, it poses theoretical centralization risk, if the attacker manages to keep PoW exploit secret. 

docs/cryptography/ed25519.md

@@ -0,0 +1,7 @@
+# Ed25519 curve
+
+Monero uses Ref10 implementation by Daniel J. Bernstein.
+
+## Reference
+
+https://stackoverflow.com/questions/19147619/what-implementions-of-ed25519-exist

docs/cryptography/keccak-256.md

@@ -0,0 +1,36 @@
+# Keccak-256 hash function
+
+Monero employs Keccak-256 as a hashing function.
+
+Keccak is the leading hashing function, designed by non-NSA designers.
+Keccak won [NIST competition](https://en.wikipedia.org/wiki/NIST_hash_function_competition) to become the official SHA3.
+
+## Uses
+
+Monero does **not** employ Keccak for Proof-of-Work. Instead, Keccak is used for:
+   
+* random number generator
+* block hashing
+* transaction hashing
+* stealth address private key image (for double spend protection)
+* public address checksum
+* RingCT
+* multisig
+* bulletproofs
+
+...and likely a few other things.
+
+## Keccak-256 vs SHA3-256
+
+SHA3-256 is Keccak-256, except NIST changed padding.
+For that reason original Keccak-256 gives in a different hash value than NIST SHA3-256.  
+
+Monero uses original Keccak-256.
+The NIST standard was only published on August 2015, while Monero went live on 18 April 2014.  
+
+## Reference
+
+* [Keccak source code used in Monero](https://github.com/monero-project/monero/blob/5c2dfe157b48a486eb2b92dcf8789b3b1eb20f60/src/crypto/keccak.c)
+* [SHA3 on Wikipedia](https://en.wikipedia.org/wiki/SHA-3)
+* [Keccak-256 vs SHA3-256](https://ethereum.stackexchange.com/questions/550/which-cryptographic-hash-function-does-ethereum-use) explained on Ethereum stackexchange
+* [Online tool to calculate Keccak-256 and SHA3-256](https://emn178.github.io/online-tools/keccak_256.html)

docs/cryptography/overview.md

@@ -0,0 +1,8 @@
+# Monero cryptography overview
+
+Monero uses a wide variety of cryptographic primitives for various use cases.
+
+Comparing to altcoins, Monero cryptography is considered conservative, sound and robust.
+
+Comparing to Bitcoin, Monero uses much more primitives, and some of them are more advanced, especially those related to privacy and Proof of Work.
+Some choices are deliberately non-standard (for better or worse) - oftentimes a legacy of the CryptoNote protocol.

docs/cryptography/prng.md

@@ -0,0 +1,18 @@
+# Monero Pseudo Random Number Generator
+
+Monero uses PRNG based on Keccak hashing function.
+
+The seed comes from entropy sources provided by operating system.
+On Linux and MacOS this translates to `/dev/urandom`.
+On Windows the WinAPI `CryptGenRandom` call is used.
+
+There is no reseeding.
+
+## Caveats
+
+* In Monero source code you can also find libsodium based random bytes generator. It is part of the embedded library and apparently is not used in actual Monero code.  
+
+## Reference
+
+* [Source code](https://github.com/monero-project/monero/blob/1a4298685aa9e694bc555ae69be59d14d3790465/src/crypto/random.c)
+* [StackExchange answer](https://monero.stackexchange.com/a/2076/3218)

docs/technical-specs.md

@@ -1,6 +1,10 @@
 # Monero Technical Specs
 
-## No premine, no instamine, no token
+## Live
+
+* Monero blockchain is live since 18 April 2014
+
+## No premine, no instamine, no ICO/token
 
 * Monero had no premine or instamine
 * Monero did not sell any token
@@ -32,7 +36,7 @@
 
 ## Emission curve
 
-**Main curve**
+**Main emission**
 
 First, the main emission is about to produce ~18.132 million coins by the end of May 2022.
 
@@ -40,7 +44,7 @@ As of Dec 2017 the emission is about 30 XMR per 10 minutes.
 
 See [charts and details](https://www.reddit.com/r/Monero/comments/512kwh/useful_for_learning_about_monero_coin_emission/).
 
-**Tail curve**
+**Tail emission**
 
 The tail emission kicks in once main emission is done.
 
@@ -60,6 +64,12 @@ This translates to <1% inflation decreasing over time.
 
 * Stealth addresses
 
-## Amount obfuscation
+## Amount privacy
 
 * Ring confidential transactions
+
+## IP address privacy
+
+* not built in
+* use TOR or I2P
+* there is an ongoing effort to integrate I2P into Monero: the Kovri project 

mkdocs.yml

@@ -10,6 +10,11 @@ pages:
 - Technical Specs: 'technical-specs.md'
 - Primitives:
     - Base58: 'primitives/base58.md'
+- Cryptography:
+    - Overview: 'cryptography/overview.md'
+    - PRNG: 'cryptography/prng.md'
+    - 'Keccak-256': 'cryptography/keccak-256.md'
+#    - CryptoNight PoW: 'cryptography/cryptonight.md'
 - Address:
     - Standard: 'public-address/standard-address.md'
     - Integrated: 'public-address/integrated-address.md'