feat: address from public key function (#673)

internal/protocols/algorand/address.go

@@ -0,0 +1,29 @@
+package algorand
+
+import (
+	"crypto/sha512"
+
+	"github.com/mailchain/mailchain/crypto"
+	"github.com/mailchain/mailchain/crypto/ed25519"
+	"github.com/pkg/errors"
+)
+
+const (
+	checksumLength = 4
+)
+
+// Address returns the address from the public key.
+func Address(pubKey crypto.PublicKey) ([]byte, error) {
+	switch pubKey.(type) {
+	case ed25519.PublicKey, *ed25519.PublicKey:
+		return append(pubKey.Bytes(), checksum(pubKey.Bytes())...), nil
+	default:
+		return nil, errors.Errorf("invalid public key type: %T", pubKey)
+	}
+}
+
+// Algorand 4-byte checksum added to public key to make an algorand address.
+func checksum(data []byte) []byte {
+	fullHash := sha512.Sum512_256(data)
+	return fullHash[len(fullHash)-checksumLength:]
+}

internal/protocols/algorand/address_test.go

@@ -0,0 +1,69 @@
+package algorand
+
+import (
+	"testing"
+
+	"github.com/mailchain/mailchain/crypto"
+	"github.com/mailchain/mailchain/crypto/ed25519/ed25519test"
+	"github.com/mailchain/mailchain/crypto/secp256k1/secp256k1test"
+	"github.com/mailchain/mailchain/crypto/sr25519/sr25519test"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAddress(t *testing.T) {
+	type args struct {
+		pubKey crypto.PublicKey
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    []byte
+		wantErr bool
+	}{
+		{
+			"sofia",
+			args{
+				ed25519test.SofiaPublicKey,
+			},
+			[]byte{0x72, 0x3c, 0xaa, 0x23, 0xa5, 0xb5, 0x11, 0xaf, 0x5a, 0xd7, 0xb7, 0xef, 0x60, 0x76, 0xe4, 0x14, 0xab, 0x7e, 0x75, 0xa9, 0xdc, 0x91, 0xe, 0xa6, 0xe, 0x41, 0x7a, 0x2b, 0x77, 0xa, 0x56, 0x71, 0x64, 0xea, 0x58, 0x50},
+			false,
+		},
+		{
+			"charlotte",
+			args{
+				ed25519test.CharlottePublicKey,
+			},
+			[]byte{0x2e, 0x32, 0x2f, 0x87, 0x40, 0xc6, 0x1, 0x72, 0x11, 0x1a, 0xc8, 0xea, 0xdc, 0xdd, 0xa2, 0x51, 0x2f, 0x90, 0xd0, 0x6d, 0xe, 0x50, 0x3e, 0xf1, 0x89, 0x97, 0x9a, 0x15, 0x9b, 0xec, 0xe1, 0xe8, 0x96, 0xc8, 0xe9, 0x2c},
+			false,
+		},
+		{
+			"err-secp256k1",
+			args{
+				secp256k1test.CharlottePublicKey,
+			},
+			nil,
+			true,
+		},
+		{
+			"err-sr25519",
+			args{
+				sr25519test.SofiaPublicKey,
+			},
+			nil,
+			true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := Address(tt.args.pubKey)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("Address() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+
+			if !assert.Equal(t, tt.want, got) {
+				t.Errorf("Address() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}