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Co-authored-by: Marie Gauthier <[email protected]>

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4 changes: 2 additions & 2 deletions docs/basics/README.md
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# Basics

This repository contains reference documentation on the basic concepts of the Cosmos SDK.
This repository contains reference documentation on the basic concepts of the Cosmos SDK.

1. [Anatomy of an SDK Application](./app-anatomy.md)
2. [Lifecycle of a transaction](./tx-lifecycle.md)
3. [Accounts](./accounts.md)
4. [Gas and Fees](./gas-fees.md)

After reading the basics, head on to the [Core Reference](../core/README.md) for more advanced material.
After reading the basics, head on to the [Core Reference](../core/README.md) for more advanced material.
72 changes: 36 additions & 36 deletions docs/basics/accounts.md
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-->

# Accounts
# Accounts

This document describes the in-built accounts system of the Cosmos SDK. {synopsis}

Expand All @@ -12,9 +12,9 @@ This document describes the in-built accounts system of the Cosmos SDK. {synopsi

## Account Definition

In the Cosmos SDK, an *account* designates a pair of *public key* `PubKey` and *private key* `PrivKey`. The `PubKey` can be derived to generate various `Addresses`, which are used to identify users (among other parties) in the application. `Addresses` are also associated with [`message`s](../building-modules/messages-and-queries.md#messages) to identify the sender of the `message`. The `PrivKey` is used to generate [digital signatures](#signatures) to prove that an `Address` associated with the `PrivKey` approved of a given `message`.
In the Cosmos SDK, an _account_ designates a pair of _public key_ `PubKey` and _private key_ `PrivKey`. The `PubKey` can be derived to generate various `Addresses`, which are used to identify users (among other parties) in the application. `Addresses` are also associated with [`message`s](../building-modules/messages-and-queries.md#messages) to identify the sender of the `message`. The `PrivKey` is used to generate [digital signatures](#signatures) to prove that an `Address` associated with the `PrivKey` approved of a given `message`.

To derive `PubKey`s and `PrivKey`s, the Cosmos SDK uses a standard called [BIP32](https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki). This standard defines how to build an HD wallet, where a wallet is a set of accounts. At the core of every account, there is a seed, which takes the form of a 12 or 24-words mnemonic. From this mnemonic, it is possible to derive any number of `PrivKey`s using one-way cryptographic function. Then, a `PubKey` can be derived from the `PrivKey`. Naturally, the mnemonic is the most sensitive information, as private keys can always be re-generated if the mnemonic is preserved.
To derive `PubKey`s and `PrivKey`s, the Cosmos SDK uses a standard called [BIP32](https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki). This standard defines how to build an HD wallet, where a wallet is a set of accounts. At the core of every account, there is a seed, which takes the form of a 12 or 24-words mnemonic. From this mnemonic, it is possible to derive any number of `PrivKey`s using one-way cryptographic function. Then, a `PubKey` can be derived from the `PrivKey`. Naturally, the mnemonic is the most sensitive information, as private keys can always be re-generated if the mnemonic is preserved.

```
Account 0 Account 1 Account 2
Expand Down Expand Up @@ -56,65 +56,65 @@ To derive `PubKey`s and `PrivKey`s, the Cosmos SDK uses a standard called [BIP32
+-------------------+
```

In the Cosmos SDK, accounts are stored and managed via an object called a [`Keybase`](#keybase).
In the Cosmos SDK, accounts are stored and managed via an object called a [`Keyring`](#keyring).

## Keybase
## Keyring

A `Keybase` is an object that stores and manages accounts. In the Cosmos SDK, a `Keybase` implementation follows the `Keybase` interface:
A `Keyring` is an object that stores and manages accounts. In the Cosmos SDK, a `Keyring` implementation follows the `Keyring` interface:

+++ https://github.com/cosmos/cosmos-sdk/blob/7d7821b9af132b0f6131640195326aa02b6751db/crypto/keys/types.go#L13-L86
+++ https://github.com/cosmos/cosmos-sdk/blob/d9175200920e96bfa4182b5c8bc46d91b17a28a1/crypto/keyring/keyring.go#L50-L88

The default implementation of `Keybase` of the Cosmos SDK is `dbKeybase`.
The default implementation of `Keyring` comes from the third-party [`99designs/keyring`](https://github.com/99designs/keyring) library.

+++ https://github.com/cosmos/cosmos-sdk/blob/7d7821b9af132b0f6131640195326aa02b6751db/crypto/keys/keybase.go
A few notes on the `Keyring` methods:

A few notes on the `Keybase` methods as implemented in `dbKeybase`:
- `Sign(uid string, msg []byte) ([]byte, tmcrypto.PubKey, error)` strictly deals with the signature of the `message` bytes. Some preliminary work should be done beforehand to prepare and encode the `message` into a canonical `[]byte` form, and this is done in the `GetSignBytes` method. See an example of `message` preparation from the `x/bank` module. Note that signature verification is not implemented in the SDK by default. It is deferred to the [`anteHandler`](#antehandler).
+++ https://github.com/cosmos/cosmos-sdk/blob/d9175200920e96bfa4182b5c8bc46d91b17a28a1/x/bank/types/msgs.go#L51-L54
- `NewAccount(uid, mnemonic, bip39Passwd, hdPath string, algo SignatureAlgo) (Info, error)` creates a new account based on the [`bip44 path`](https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki) and persists it on disk (note that the `PrivKey` is [encrypted with a passphrase before being persisted](https://github.com/cosmos/cosmos-sdk/blob/d9175200920e96bfa4182b5c8bc46d91b17a28a1/crypto/keys/mintkey/mintkey.go), it is **never stored unencrypted**). In the context of this method, the `account` and `address` parameters refer to the segment of the BIP44 derivation path (e.g. `0`, `1`, `2`, ...) used to derive the `PrivKey` and `PubKey` from the mnemonic (note that given the same mnemonic and `account`, the same `PrivKey` will be generated, and given the same `account` and `address`, the same `PubKey` and `Address` will be generated). Finally, note that the `NewAccount` method derives keys and addresses using the algorithm specified in the last argument `algo`. Currently, the SDK supports two public key algorithms:
- `secp256k1`, as implemented in the [SDK's `crypto/keys/secp256k1` package](https://github.com/cosmos/cosmos-sdk/blob/d9175200920e96bfa4182b5c8bc46d91b17a28a1/crypto/keys/secp256k1/secp256k1.go),
- `ed25519`, as implemented in the [SDK's `crypto/keys/ed25519` package](https://github.com/cosmos/cosmos-sdk/blob/d9175200920e96bfa4182b5c8bc46d91b17a28a1/crypto/keys/ed25519/ed25519.go).
- `ExportPrivKeyArmor(uid, encryptPassphrase string) (armor string, err error)` exports a private key in ASCII-armored encrypted format, using the given passphrase. You can then either import it again into the keyring using the `ImportPrivKey(uid, armor, passphrase string)` function, or decrypt it into a raw private key using the `UnarmorDecryptPrivKey(armorStr string, passphrase string)` function.

- `Sign(name, passphrase string, msg []byte) ([]byte, crypto.PubKey, error)` strictly deals with the signature of the `message` bytes. Some preliminary work should be done beforehand to prepare and encode the `message` into a canonical `[]byte` form. See an example of `message` preparation from the `auth` module. Note that signature verification is not implemented in the SDK by default. It is deferred to the [`anteHandler`](#antehandler).
+++ https://github.com/cosmos/cosmos-sdk/blob/7d7821b9af132b0f6131640195326aa02b6751db/x/auth/types/txbuilder.go#L176-L209
- `CreateMnemonic(name string, language Language, passwd string, algo SigningAlgo) (info Info, seed string, err error)` creates a new mnemonic and prints it in the logs, but it **does not persist it on disk**.
- `CreateAccount(name, mnemonic, bip39Passwd, encryptPasswd string, account uint32, index uint32) (Info, error)` creates a new account based on the [`bip44 path`](https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki) and persists it on disk (note that the `PrivKey` is [encrypted with a passphrase before being persisted](https://github.com/cosmos/cosmos-sdk/blob/7d7821b9af132b0f6131640195326aa02b6751db/crypto/keys/mintkey/mintkey.go), it is **never stored unencrypted**). In the context of this method, the `account` and `address` parameters refer to the segment of the BIP44 derivation path (e.g. `0`, `1`, `2`, ...) used to derive the `PrivKey` and `PubKey` from the mnemonic (note that given the same mnemonic and `account`, the same `PrivKey` will be generated, and given the same `account` and `address`, the same `PubKey` and `Address` will be generated). Finally, note that the `CreateAccount` method derives keys and addresses using `secp256k1` as implemented in the [Tendermint library](https://github.com/tendermint/tendermint/tree/bc572217c07b90ad9cee851f193aaa8e9557cbc7/crypto/secp256k1). As a result, it only works for creating account keys and addresses, not consensus keys. See [`Addresses`](#addresses) for more.

The current implementation of `dbKeybase` is basic and does not offer on-demand locking. If an instance of `dbKeybase` is created, the underlying `db` is locked meaning no other process can access it besides the one in which it was instantiated. This is the reason why the default SDK client uses another implementation of the `Keybase` interface called `lazyKeybase`:


+++ https://github.com/cosmos/cosmos-sdk/blob/7d7821b9af132b0f6131640195326aa02b6751db/crypto/keys/lazy_keybase.go

`lazyKeybase` is simple wrapper around `dbKeybase` which locks the database only when operations are to be performed and unlocks it immediately after. With the `lazyKeybase`, it is possible for the [command-line interface](../interfaces/cli.md) to create a new account while the [rest server](../interfaces/rest.md) is running. It is also possible to pipe multiple CLI commands.
Also see the [`Addresses`](#addresses) section for more information.

## Addresses and PubKeys

`Addresses` and `PubKey`s are both public information that identify actors in the application. There are 3 main types of `Addresses`/`PubKeys` available by default in the Cosmos SDK:

- Addresses and Keys for **accounts**, which identify users (e.g. the sender of a `message`). They are derived using the **`secp256k1`** curve.
- Addresses and Keys for **validator operators**, which identify the operators of validators. They are derived using the **`secp256k1`** curve.
- Addresses and Keys for **accounts**, which identify users (e.g. the sender of a `message`). They are derived using the **`secp256k1`** curve.
- Addresses and Keys for **validator operators**, which identify the operators of validators. They are derived using the **`secp256k1`** curve.
- Addresses and Keys for **consensus nodes**, which identify the validator nodes participating in consensus. They are derived using the **`ed25519`** curve.

| | Address bech32 Prefix | Pubkey bech32 Prefix | Curve | Address byte length | Pubkey byte length |
|--------------------|-----------------------|----------------------|-------------|---------------------|--------------------|
| ------------------ | --------------------- | -------------------- | ----------- | ------------------- | ------------------ |
| Accounts | cosmos | cosmospub | `secp256k1` | `20` | `33` |
| Validator Operator | cosmosvaloper | cosmosvaloperpub | `secp256k1` | `20` | `33` |
| Consensus Nodes | cosmosvalcons | cosmosvalconspub | `ed25519` | `20` | `32` |
| Consensus Nodes | cosmosvalcons | cosmosvalconspub | `ed25519` | `20` | `32` |

### PubKeys

`PubKey`s used in the Cosmos SDK follow the `Pubkey` interface defined in tendermint's `crypto` package:
`PubKey`s used in the Cosmos SDK are Protobuf messages and extend the `Pubkey` interface defined in tendermint's `crypto` package:

+++ https://github.com/cosmos/cosmos-sdk/blob/d9175200920e96bfa4182b5c8bc46d91b17a28a1/crypto/types/types.go#L8-L13

+++ https://github.com/tendermint/tendermint/blob/01c32c62e8840d812359c9e87e9c575aa67acb09/crypto/crypto.go#L22-L28

+++ https://github.com/tendermint/tendermint/blob/bc572217c07b90ad9cee851f193aaa8e9557cbc7/crypto/crypto.go#L22-L27
- For `secp256k1` keys, the actual implementation can be found [here](https://github.com/cosmos/cosmos-sdk/blob/d9175200920e96bfa4182b5c8bc46d91b17a28a1/crypto/keys/secp256k1/secp256k1.go).
- For `ed25519` keys, it can be found [here](https://github.com/cosmos/cosmos-sdk/blob/d9175200920e96bfa4182b5c8bc46d91b17a28a1/crypto/keys/ed25519/ed25519.go).

For `secp256k1` keys, the actual implementation can be found [here](https://github.com/tendermint/tendermint/blob/bc572217c07b90ad9cee851f193aaa8e9557cbc7/crypto/secp256k1/secp256k1.go#L140). For `ed25519` keys, it can be found [here](https://github.com/tendermint/tendermint/blob/bc572217c07b90ad9cee851f193aaa8e9557cbc7/crypto/ed25519/ed25519.go#L135).
In both case, the actual key (as raw bytes) is the compressed form of the pubkey. The first byte is a `0x02` byte if the `y`-coordinate is the lexicographically largest of the two associated with the `x`-coordinate. Otherwise the first byte is a `0x03`. This prefix is followed with the `x`-coordinate.

Note that in the Cosmos SDK, `Pubkeys` are not manipulated in their raw form. Instead, they are double encoded using [`Amino`](../core/encoding.md#amino) and [`bech32`](https://en.bitcoin.it/wiki/Bech32). In the SDK is done by first calling the `Bytes()` method on the raw `Pubkey` (which applies amino encoding), and then the `ConvertAndEncode` method of `bech32`.
Note that in the Cosmos SDK, `Pubkeys` are not manipulated in their raw bytes form. Instead, they are encoded to string using [`Amino`](../core/encoding.md#amino) and [`bech32`](https://en.bitcoin.it/wiki/Bech32). In the SDK, it is done by first calling the `Bytes()` method on the raw `Pubkey` (which applies amino encoding), and then the `ConvertAndEncode` method of `bech32`.

+++ https://github.com/cosmos/cosmos-sdk/blob/7d7821b9af132b0f6131640195326aa02b6751db/types/address.go#L579-L729
+++ https://github.com/cosmos/cosmos-sdk/blob/d9175200920e96bfa4182b5c8bc46d91b17a28a1/types/address.go#L579-L729

### Addresses

The Cosmos SDK comes by default with 3 types of addresses:

- `AccAddress` for accounts.
- `ValAddress` for validator operators.
- `ConsAddress` for validator nodes.
- `ValAddress` for validator operators.
- `ConsAddress` for validator nodes.

Each of these address types are an alias for an hex-encoded `[]byte` array of length 20. Here is the standard way to obtain an address `aa` from a `Pubkey pub`:

Expand All @@ -124,12 +124,12 @@ aa := sdk.AccAddress(pub.Address().Bytes())

These addresses implement the `Address` interface:

+++ https://github.com/cosmos/cosmos-sdk/blob/7d7821b9af132b0f6131640195326aa02b6751db/types/address.go#L71-L80
+++ https://github.com/cosmos/cosmos-sdk/blob/d9175200920e96bfa4182b5c8bc46d91b17a28a1/types/address.go#L73-L82

Of note, the `Marhsal()` and `Bytes()` method both return the same raw `[]byte` form of the address, the former being needed for Protobuff compatibility. Also, the `String()` method is used to return the `bech32` encoded form of the address, which should be the only address format with which end-user interract. Next is an example:
Of note, the `Marshal()` and `Bytes()` method both return the same raw `[]byte` form of the address, the former being needed for Protobuf compatibility. Also, the `String()` method is used to return the `bech32` encoded form of the address, which should be the only address format with which end-user interract. Here is an example:

+++ https://github.com/cosmos/cosmos-sdk/blob/7d7821b9af132b0f6131640195326aa02b6751db/types/address.go#L229-L243
+++ https://github.com/cosmos/cosmos-sdk/blob/d9175200920e96bfa4182b5c8bc46d91b17a28a1/types/address.go#L232-L246

## Next {hide}

Learn about [gas and fees](./gas-fees.md) {hide}
Learn about [gas and fees](./gas-fees.md) {hide}
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