ADR-28 derive address functions

CHANGELOG.md

@@ -42,6 +42,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * [\#8786](https://github.com/cosmos/cosmos-sdk/pull/8786) Enabled secp256r1 in x/auth.
 * (rosetta) [\#8729](https://github.com/cosmos/cosmos-sdk/pull/8729) Data API fully supports balance tracking. Construction API can now construct any message supported by the application.
 * [\#8754](https://github.com/cosmos/cosmos-sdk/pull/8875) Added support for reverse iteration to pagination.
+* [#9088](https://github.com/cosmos/cosmos-sdk/pull/9088) Added implementation to ADR-28 Derived Addresses.
 
 ### Client Breaking Changes
 
@@ -78,6 +79,9 @@ Ref: https://keepachangelog.com/en/1.0.0/
   * `MsgCreateValidator.Pubkey` type changed from `string` to `codectypes.Any`.
 * (client) [\#8926](https://github.com/cosmos/cosmos-sdk/pull/8926) `client/tx.PrepareFactory` has been converted to a private function, as it's only used internally.
 * (auth/tx) [\#8926](https://github.com/cosmos/cosmos-sdk/pull/8926) The `ProtoTxProvider` interface used as a workaround for transaction simulation has been removed.
+* [#9088](https://github.com/cosmos/cosmos-sdk/pull/9088) Unify naming of the ADR-28 related functions: Renames: `address.NewCompose` -> `address.Compose`, `address.NewCompose`
+
+
 
 ### State Machine Breaking
 

docs/architecture/adr-028-public-key-addresses.md

@@ -135,7 +135,7 @@ type Addressable interface {
     Address() []byte
 }
 
-func NewComposed(typ string, subaccounts []Addressable) []byte {
+func Composed(typ string, subaccounts []Addressable) []byte {
     addresses = map(subaccounts, \a -> LengthPrefix(a.Address()))
     addresses = sort(addresses)
     return address.Hash(typ, addresses[0] + ... + addresses[n])
@@ -175,7 +175,7 @@ func (multisig PubKey) Address() {
   prefix := fmt.Sprintf("%s/%d", proto.MessageName(multisig), multisig.Threshold)
 
   // use the Composed function defined above
-  return address.NewComposed(prefix, keys)
+  return address.Composed(prefix, keys)
 }
 ```
 
@@ -185,14 +185,14 @@ NOTE: this section is not finalize and it's in active discussion.
 
 In Basic Address section we defined a module account address as:
 
-```
+```go
 address.Hash("module", moduleName)
 ```
 
 We use `"module"` as a schema type for all module derived addresses. Module accounts can have sub accounts. The derivation process has a defined order: module name, submodule key, subsubmodule key.
 Module account addresses are heavily used in the SDK so it makes sense to optimize the derivation process: instead of using of using `LengthPrefix` for the module name, we use a null byte (`'\x00'`) as a separator. This works, because null byte is not a part of a valid module name.
 
-```
+```go
 func Module(moduleName string, key []byte) []byte{
 	return Hash("module", []byte(moduleName) + 0 + key)
 }
@@ -208,20 +208,30 @@ If we want to create an address for a module account depending on more than one
 btcAtomAMM := address.Module("amm", btc.Addrress() + atom.Address()})
 ```
 
-We can continue the derivation process and can create an address for a submodule account.
+#### Derived Addresses
 
-```
-func Submodule(address []byte, derivationKey []byte) {
-    return Hash("module", address + derivationKey)
+We must be able to cryptographically derive one address from another one. The derivation process must guarantee hash properties, hence we use the already defined `Hash` function:
+
+```go
+func Derive(address []byte, derivationKey []byte) []byte {
+    return Hash(addres, derivationKey)
 }
 ```
 
-NOTE: if `address` is not a hash based address (with `LEN` length) then we should use `LengthPrefix`. An alternative would be to use one `Module` function, which takes a slice of keys and mapped with `LengthPrefix`. For final version we need to validate what's the most common use.
-
+Note: `Module` is a special case of the more general _derived_ address, where we set the `"module"` string for the _from address_.
 
 **Example**  For a cosmwasm smart-contract address we could use the following construction:
 ```
-smartContractAddr := Submodule(Module("cosmwasm", smartContractsNamespace), smartContractKey)
+smartContractAddr := Derived(Module("cosmwasm", smartContractsNamespace), []{smartContractKey})
+```
+
+We can also define a function which will derive an address based on multiple keys (path). The function is similar to the `Composed`, however it doesn't sort the derivation keys:
+
+```go
+func DeriveMulti(address []byte, derivationKeys [][]byte) []byte {
+    keys = map(derivationKeys, \k -> LengthPrefix(k))
+    return Hash(LengthPrefix(address), keys[0] + ... + keys[n])
+}
 ```
 
 

types/address/hash.go

@@ -32,8 +32,8 @@ func Hash(typ string, key []byte) []byte {
 	return hasher.Sum(nil)
 }
 
-// NewComposed creates a new address based on sub addresses.
-func NewComposed(typ string, subAddresses []Addressable) ([]byte, error) {
+// Compose creates a new address based on sub addresses.
+func Compose(typ string, subAddresses []Addressable) ([]byte, error) {
 	as := make([][]byte, len(subAddresses))
 	totalLen := 0
 	var err error
@@ -62,3 +62,24 @@ func Module(moduleName string, key []byte) []byte {
 	mKey := append([]byte(moduleName), 0)
 	return Hash("module", append(mKey, key...))
 }
+
+// Derive derives a new address from the main `address` and a derivation `key`.
+func Derive(address []byte, key []byte) []byte {
+	return Hash(conv.UnsafeBytesToStr(address), key)
+}
+
+// DeriveMulti generalizes `Derive` function for multiple keys - `path`. The keys are order
+// sensitive. Changing an order of the elements in the path will create a different key.
+// NOTE: DeriveMulti(addr, [k1, k2]) != Derive(Derive(addr, k1), k2)
+//                                   != Derive(Derive(addr, k2), k1)
+func DeriveMulti(address []byte, path [][]byte) ([]byte, error) {
+	key := []byte{}
+	for i, p := range path {
+		a, err := LengthPrefix(p)
+		if err != nil {
+			return nil, fmt.Errorf("a path key=%v at index=%d is not compatible [%w]", p, i, err)
+		}
+		key = append(key, a...)
+	}
+	return Hash(conv.UnsafeBytesToStr(address), key), nil
+}

types/address/hash_test.go

@@ -34,7 +34,7 @@ func (suite *AddressSuite) TestComposed() {
 	a2 := addrMock{[]byte{21, 22}}
 
 	typ := "multisig"
-	ac, err := NewComposed(typ, []Addressable{a1, a2})
+	ac, err := Compose(typ, []Addressable{a1, a2})
 	assert.NoError(err)
 	assert.Len(ac, Len)
 
@@ -45,18 +45,18 @@ func (suite *AddressSuite) TestComposed() {
 	assert.Equal(ac, ac2, "NewComposed works correctly")
 
 	// changing order of addresses shouldn't impact a composed address
-	ac2, err = NewComposed(typ, []Addressable{a2, a1})
+	ac2, err = Compose(typ, []Addressable{a2, a1})
 	assert.NoError(err)
 	assert.Len(ac2, Len)
 	assert.Equal(ac, ac2, "NewComposed is not sensitive for order")
 
 	// changing a type should change composed address
-	ac2, err = NewComposed(typ+"other", []Addressable{a2, a1})
+	ac2, err = Compose(typ+"other", []Addressable{a2, a1})
 	assert.NoError(err)
 	assert.NotEqual(ac, ac2, "NewComposed must be sensitive to type")
 
 	// changing order of addresses shouldn't impact a composed address
-	ac2, err = NewComposed(typ, []Addressable{a1, addrMock{make([]byte, 300, 300)}})
+	ac2, err = Compose(typ, []Addressable{a1, addrMock{make([]byte, 300, 300)}})
 	assert.Error(err)
 	assert.Contains(err.Error(), "should be max 255 bytes, got 300")
 }
@@ -75,6 +75,36 @@ func (suite *AddressSuite) TestModule() {
 	assert.NotEqual(addr2, addr3, "changing key must change address")
 }
 
+func (suite *AddressSuite) TestDerive() {
+	assert := suite.Assert()
+	var addr, key1, key2 = []byte{1, 2}, []byte{3, 4}, []byte{1, 2}
+	d1 := Derive(addr, key1)
+	d2 := Derive(addr, key2)
+	d3 := Derive(key1, key2)
+	assert.Len(d1, Len)
+	assert.Len(d2, Len)
+	assert.Len(d3, Len)
+
+	assert.NotEqual(d1, d2)
+	assert.NotEqual(d1, d3)
+	assert.NotEqual(d2, d3)
+}
+
+func (suite *AddressSuite) TestDeriveMulti() {
+	assert := suite.Assert()
+	var addr, key1, key2 = []byte{1, 2}, []byte{3, 4}, []byte{1, 2}
+	d1, err := DeriveMulti(addr, [][]byte{key1, key2})
+	assert.NoError(err)
+	d2, err := DeriveMulti(addr, [][]byte{key2, key1})
+	assert.NoError(err)
+
+	assert.NotEqual(d1, d2)
+	d3 := Derive(Derive(addr, key1), key2)
+	assert.NotEqual(d1, d3)
+	d3 = Derive(Derive(addr, key2), key1)
+	assert.NotEqual(d1, d3)
+}
+
 type addrMock struct {
 	Addr []byte
 }