update README

README.md

@@ -10,64 +10,60 @@ easier way to install MMGen, check out the prebuilt bootable USB images on the
 
 MMGen is a wallet and cold storage solution for Bitcoin (and selected altcoins)
 implemented as a suite of lightweight Python scripts.  The scripts work in
-tandem with a reference Bitcoin Core daemon (or altcoin daemon) running on both
-an online and offline computer to provide a robust solution for securely
-storing, tracking, sending and receiving Bitcoins.
-
-The online computer is used only for tracking balances and creating and sending
-transactions.  Thus it holds no private keys that can be hacked or stolen.
-All transactions are signed offline: **your seed and private keys never touch a
-network-connected device.**  The offline computer used for wallet creation,
-address generation and transaction signing is typically a low-powered device
-such as a Raspberry Pi.
-
-MMGen is designed for reliability by having the Bitcoin daemon itself, rather
-than less-tested third-party software, do all the “heavy lifting” of tracking
-and signing transactions.  It’s also designed with privacy in mind: unlike some
-other online/offline wallet solutions, MMGen plus Bitcoin Core is a completely
-self-contained system that makes **no connections to the Internet** except for
-the Bitcoin network itself: no third parties are involved, and thus no
-information about the addresses you’re tracking is leaked to the outside
-world.
+tandem with a reference Bitcoin or altcoin daemon running on both online and
+offline computers to provide a robust solution for securely storing, tracking,
+sending and receiving your crypto assets.
+
+The online computer is used for tracking balances and creating and sending
+transactions, while the offline computer (typically an air-gapped, low-power
+device such as a Raspberry Pi) takes care of wallet creation, address generation
+and transaction signing.  All operations involving secret data are handled
+offline: **your seed and private keys never come into contact with a
+network-connected device.**
+
+MMGen is designed for reliability by having the reference Bitcoin or altcoin
+daemon, rather than less-tested third-party software, do all the “heavy lifting”
+of tracking and signing transactions.  It’s also designed with privacy in mind:
+unlike some other online/offline wallets, MMGen is a completely self-contained
+system that makes **no connections to the Internet** apart from the coin network
+itself: no information about which addresses you’re tracking is ever leaked to
+the outside world.
 
 Like all deterministic wallets, MMGen can generate a virtually unlimited number
 of address/key pairs from a single seed.  Your wallet never changes, so you need
 back it up only once.
 
 At the heart of the MMGen system is the seed, the “master key” providing access
-to all your Bitcoins.  The seed can be stored in five different ways:
+to all your crypto assets.  The seed can be stored in five different ways:
 
-  1. as a password-encrypted wallet.  For password hashing, the crack-resistant
-	 scrypt hash function is used.  Scrypt’s parameters can be tuned on the
-	 command line to make your wallet’s password virtually impossible to crack
-	 should it fall into the wrong hands.  The wallet is a tiny, six-line text
-	 file suitable for printing or even writing out by hand;
+  1. as a password-encrypted wallet.  The crack-resistant Scrypt hash function
+	 is used for password hashing.  Scrypt’s parameters can be tuned to make
+	 your wallet’s password very difficult to crack should it fall into the
+	 wrong hands.  The wallet is a compact, six-line text file suitable for
+	 printing or even writing out by hand;
 
   2. as a seed file: a one-line, conveniently formatted base-58 representation
 	 of your unencrypted seed plus a checksum;
 
-  3. as an Electrum-like mnemonic of 12, 18 or 24 words;
+  3. as an Electrum-like mnemonic seed phrase of 12, 18 or 24 words;
 
   4. as a brainwallet passphrase (this option is recommended only for users who
 	 understand the risks of brainwallets and know how to create a strong
-	 brainwallet passphrase).  The brainwallet is hashed using scrypt with
-	 tunable parameters, making it much harder to crack than standard SHA-256
+	 brainwallet passphrase).  The brainwallet is hashed using Scrypt with
+	 tunable parameters, making it much harder to crack than standard SHA256
 	 brainwallets; or
 
-  5. as “incognito data”, an MMGen wallet encrypted to make it indistinguishable
-	 from random data.  This data can be hidden in and retrieved from a
-	 random-data filled disk partition or file at an offset of your choice.
-	 This makes it possible to hide a wallet in a public location -- on cloud
-	 storage, for example.  Incognito wallet hiding/retrieval is seamlessly
-	 integrated into MMGen, making its use nearly as easy as that of the
-	 standard wallet.
+  5. as “incognito data”, a wallet encrypted to make it indistinguishable
+	 from random data.  This data can be hidden on a disk partition filled with
+	 random data, or in a file at an offset of your choice.  This makes it
+	 possible to hide a wallet at a non-private location—on cloud storage, for
+	 example.  Incognito wallet hiding/retrieval is seamlessly integrated into
+	 MMGen, making its use nearly as easy as that of the standard wallet.
 
 The best part is that all these methods can be combined.  If you forget your
-mnemonic, for example, you can regenerate it and your keys from the stored
-wallet or seed file.  Correspondingly, a lost wallet can be regenerated from the
-mnemonic or seed or a lost seed from the wallet or mnemonic.  Keys from a
-forgotten brainwallet can be recovered from the brainwallet’s corresponding
-wallet file.
+mnemonic seed phrase, for example, you can regenerate it from a stored wallet
+or seed file.  Correspondingly, a lost wallet can be regenerated from a mnemonic
+or seed or vice-versa.
 
 ***mmgen-txcreate running in a terminal window***
 ![mmgen-txcreate running in a terminal window][9]
@@ -75,16 +71,16 @@ wallet file.
 #### Simplified key derivation and seed-phrase generation
 
 To deterministically derive its keys, MMGen uses a non-hierarchical scheme
-differing from the one used by most of today's popular wallets based on the
-BIP32 protocol.  One advantage of this simple, hash-based scheme is that users
-can easily [recover their private keys from their seed without the MMGen program
-itself][r] using standard command-line utilities.
+differing from the BIP32 protocol on which most of today’s popular wallets are
+based.  One advantage of this simple, hash-based scheme is that you can easily
+[recover your private keys from your seed without the MMGen program itself][K]
+using standard command-line utilities.
 
 MMGen also differs from most cryptocurrency wallets today in its use of the
 original 1626-word [Electrum wordlist][ew] for mnemonic seed phrases.  Seed
-phrases are derived using ordinary base conversion, allowing users to recover
-their seeds from them in the absence of the MMGen program itself, should the
-need arise.  An example of how to do this at the Python prompt is provided
+phrases are derived using ordinary base conversion, similarly allowing you to
+regenerate your seed from your seed phrase without MMGen program itself, should
+the need arise.  An example of how to do this at the Python prompt is provided
 [here.][S]
 
 The original Electrum wordlist was derived from a [frequency list][fl] of words
@@ -92,6 +88,63 @@ found in contemporary English poetry.  The high emotional impact of these words
 makes seed phrases easy to memorize.  Curiously, only 861 of them are shared by
 the more prosaic 2048-word [BIP39 wordlist][bw] used in most wallets today.
 
+#### A brief overview of MMGen’s unique feature set:
+
+- **[Full transaction and address tracking support][T]** for Bitcoin, [Bcash][bx],
+  [Litecoin][bx], [Ethereum][E], Ethereum Classic and [ERC20 tokens][E].
+- **[Address generation support][ag]** for the above coins, plus [Monero][mx],
+  [Zcash][zx] (t and z addresses) and [144 Bitcoin-derived altcoins][ax].
+- **Support for all Bitcoin address types** including segwit-p2sh and bech32.
+- **Independent key derivation for each address type:** No two addresses ever
+  share the same private key.  Certain wallets in wide use today regrettably
+  fail to guarantee this property, leading to the danger of inadvertent key
+  reuse.
+- **Coin control:** You select the outputs your transaction will spend.  An
+  essential requirement for maintaining anonymity.
+- **[BIP69 transaction input and output ordering][69]** helps anonymize the
+  “signature” of your transactions.
+- **[Full control over transaction fees][M]:** Fees are specified as absolute or
+  sat/byte amounts and can be adjusted interactively, letting you round fees to
+  improve anonymity.  Network fee estimation is available. [RBF][R] and [fee
+  bumping][B] are supported.
+- **Support for six wallet formats:** three encrypted (native wallet,
+  brainwallet, incognito wallet) and three unencrypted (mnemonic, mmseed,
+  hexseed).
+- **[Subwallets][U]:** Subwallets have many applications, the most notable being
+  online hot wallets and travel wallets.  MMGen subwallets are functionally and
+  externally identical to ordinary wallets, which provides a key security
+  benefit: only the user who generated the subwallet knows that it is indeed a
+  subwallet.  Subwallets don’t need to be backed up, as they can always be
+  regenerated from their parent.
+- **[Transaction autosigning][X]:** This feature puts your offline signing
+  machine into “hands-off” mode, allowing you to transact directly from cold
+  storage securely and conveniently.  Additional LED signaling support is
+  provided for RPi and Armbian-based boards.
+- **[Password generation][G]:** MMGen can be used to generate and manage your
+  online passwords.  Passwords are identified by arbitrarily chosen strings like
+  “alice@github” or “bob@reddit”.
+- **Selectable seed lengths** of 128, 192 or 256 bits.  Subwallets may have
+  shorter seeds than their parent.
+- **User-enhanced entropy:** All operations requiring random data will prompt
+  you for additional entropy from the keyboard.  Keystroke timings are used in
+  addition to the characters typed.
+- **Wallet-free operation:** All wallet operations can be performed directly
+  from your seed phrase at the prompt, allowing you to dispense with a
+  physically stored wallet entirely if you wish.
+- **Stealth mnemonic entry:** To guard against acoustic side-channel attacks,
+  you can obfuscate your seed phrase with “dead” keystrokes as you enter it from
+  the keyboard.
+- **Network privacy:** MMGen never “calls home” or checks for upgrades over the
+  network.  No information about your wallet installation or crypto assets is
+  ever leaked to third parties.
+- **Human-readable wallet files:** All of MMGen’s wallet formats, with the
+  exception of incognito wallets, can be printed or copied by hand.
+- **Terminal-based:** MMGen can be run in a screen or tmux session on your local
+  network.
+- **Scriptability:** Most MMGen commands can be made non-interactive, allowing
+  you to automate repetitive tasks using shell scripts.  Most of the
+  `mmgen-tool` utility’s commands can be piped.
+
 ### Download/Install
 
 > #### [Install a prebuilt bootable image (MMGenLive) on a USB stick][8]
@@ -105,13 +158,13 @@ the more prosaic 2048-word [BIP39 wordlist][bw] used in most wallets today.
 
 > #### [Getting Started with MMGen][3]
 
-> #### [MMGen Quick Start with Regtest Mode][q]
+> #### [MMGen Quick Start with Regtest Mode][Q]
 
 > #### [MMGen command help][6]
 
-> #### [Recovering your keys without the MMGen software][r]
+> #### [Recovering your keys without the MMGen software][K]
 
-> #### [Altcoin and Forkcoin support (ETH,ETC,XMR,ZEC,LTC,BCH and 144 Bitcoin-derived alts)][f]
+> #### [Altcoin and Forkcoin support (ETH,ETC,XMR,ZEC,LTC,BCH and 144 Bitcoin-derived alts)][F]
 
 > #### [Subwallets][U]
 
@@ -129,16 +182,28 @@ Donate (BTC,BCH): 15TLdmi5NYLdqmtCqczUs5pBPkJDXRs83w
 [4]: https://bitcointalk.org/index.php?topic=567069.0
 [5]: https://github.com/mmgen/mmgen/wiki/MMGen-Signing-Keys
 [6]: https://github.com/mmgen/mmgen/wiki/MMGen-command-help
-[q]: https://github.com/mmgen/mmgen/wiki/MMGen-Quick-Start-with-Regtest-Mode
 [7]: http://bitcoinmagazine.com/8396/deterministic-wallets-advantages-flaw/
 [8]: https://github.com/mmgen/MMGenLive
 [9]: https://cloud.githubusercontent.com/assets/6071028/20677261/6ccab1bc-b58a-11e6-8ab6-094f88befef2.jpg
-[r]: https://github.com/mmgen/mmgen/wiki/Recovering-Your-Keys-Without-the-MMGen-Software
+[Q]: https://github.com/mmgen/mmgen/wiki/MMGen-Quick-Start-with-Regtest-Mode
+[K]: https://github.com/mmgen/mmgen/wiki/Recovering-Your-Keys-Without-the-MMGen-Software
 [S]: https://github.com/mmgen/mmgen/wiki/Recovering-Your-Keys-Without-the-MMGen-Software#a_mh
-[f]: https://github.com/mmgen/mmgen/wiki/Altcoin-and-Forkcoin-Support
-[z]: https://user-images.githubusercontent.com/6071028/31656274-a35a1252-b31a-11e7-93b7-3d666f50f70f.png
-[w]: https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki
+[F]: https://github.com/mmgen/mmgen/wiki/Altcoin-and-Forkcoin-Support
+[W]: https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki
 [ew]: https://github.com/spesmilo/electrum/blob/1.9.5/lib/mnemonic.py
 [bw]: https://github.com/bitcoin/bips/blob/master/bip-0039/english.txt
 [fl]: https://en.wiktionary.org/wiki/Wiktionary:Frequency_lists/Contemporary_poetry
 [U]: https://github.com/mmgen/mmgen/wiki/Subwallets
+[X]: https://github.com/mmgen/mmgen/wiki/autosign-[MMGen-command-help]
+[G]: https://github.com/mmgen/mmgen/wiki/passgen-[MMGen-command-help]
+[T]: https://github.com/mmgen/mmgen/wiki/Getting-Started-with-MMGen#a_ct
+[E]: https://github.com/mmgen/mmgen/wiki/Altcoin-and-Forkcoin-Support#a_tx
+[ag]: https://github.com/mmgen/mmgen/wiki/addrgen-[MMGen-command-help]
+[bx]: https://github.com/mmgen/mmgen/wiki/Altcoin-and-Forkcoin-Support#a_bch
+[mx]: https://github.com/mmgen/mmgen/wiki/Altcoin-and-Forkcoin-Support#a_xmr
+[zx]: https://github.com/mmgen/mmgen/wiki/Altcoin-and-Forkcoin-Support#a_zec
+[ax]: https://github.com/mmgen/mmgen/wiki/Altcoin-and-Forkcoin-Support#a_kg
+[M]: https://github.com/mmgen/mmgen/wiki/Getting-Started-with-MMGen#a_fee
+[R]: https://github.com/mmgen/mmgen/wiki/Getting-Started-with-MMGen#a_rbf
+[B]: https://github.com/mmgen/mmgen/wiki/txbump-[MMGen-command-help]
+[69]: https://github.com/bitcoin/bips/blob/master/bip-0069.mediawiki