feat: Add encrypt-data CLI (#529)

Co-authored-by: gyuguen <gyuguen.jang@medibloc.org>

cmd/panacead/cmd/encrypt_data.go

@@ -0,0 +1,108 @@
+package cmd
+
+import (
+	"encoding/base64"
+	"encoding/hex"
+	"os"
+
+	"github.com/btcsuite/btcd/btcec"
+	"github.com/cosmos/cosmos-sdk/client"
+	"github.com/cosmos/cosmos-sdk/client/flags"
+	"github.com/cosmos/cosmos-sdk/crypto/keyring"
+	"github.com/medibloc/panacea-core/v2/crypto"
+	oracletypes "github.com/medibloc/panacea-core/v2/x/oracle/types"
+	"github.com/spf13/cobra"
+	"github.com/tendermint/tendermint/libs/cli"
+)
+
+func EncryptDataCmd(defaultNodeHome string) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "encrypt-data [input-file-path] [output-file-path] [key-name]",
+		Short: "Encrypt data with shared key which consists of oracle public key and provider's private key",
+		Long: `
+			This command can encrypt data with shared key which consists of oracle public key and provider's private key.
+			The key to be used for encryption should be stored in the localStore.
+			If not stored, please add the key first via the following command.
+			panacead keys add ...
+		`,
+		Args: cobra.ExactArgs(3),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			clientCtx, err := client.GetClientQueryContext(cmd)
+			if err != nil {
+				return err
+			}
+
+			queryClient := oracletypes.NewQueryClient(clientCtx)
+
+			origData, err := os.ReadFile(args[0])
+			if err != nil {
+				return err
+			}
+
+			params, err := queryClient.Params(cmd.Context(), &oracletypes.QueryOracleParamsRequest{})
+			if err != nil {
+				return err
+			}
+
+			oraclePubKey := params.GetParams().GetOraclePublicKey()
+
+			encryptedData, err := encrypt(clientCtx, args[2], origData, oraclePubKey)
+			if err != nil {
+				return err
+			}
+
+			if err := os.WriteFile(args[1], encryptedData, 0644); err != nil {
+				return err
+			}
+
+			return nil
+		},
+	}
+
+	cmd.PersistentFlags().String(flags.FlagHome, defaultNodeHome, "The application home directory")
+	cmd.PersistentFlags().String(flags.FlagKeyringDir, "", "The client Keyring directory; if omitted, the default 'home' directory will be used")
+	cmd.PersistentFlags().String(flags.FlagKeyringBackend, flags.DefaultKeyringBackend, "Select keyring's backend (os|file|test)")
+	cmd.PersistentFlags().String(cli.OutputFlag, "text", "Output format (text|json)")
+	cmd.PersistentFlags().String(flags.FlagChainID, "", "The network chain ID")
+
+	flags.AddQueryFlagsToCmd(cmd)
+
+	return cmd
+}
+
+func encrypt(clientCtx client.Context, keyName string, origData []byte, oraclePubKeyStr string) ([]byte, error) {
+	// get unsafe export private key from keystore
+	privKeyHex, err := keyring.NewUnsafe(clientCtx.Keyring).UnsafeExportPrivKeyHex(keyName)
+	if err != nil {
+		return nil, err
+	}
+
+	privKeyBz, err := hex.DecodeString(privKeyHex)
+	if err != nil {
+		return nil, err
+	}
+
+	privKey, _ := btcec.PrivKeyFromBytes(btcec.S256(), privKeyBz)
+
+	// oracle public key
+	oraclePubKeyBz, err := base64.StdEncoding.DecodeString(oraclePubKeyStr)
+	if err != nil {
+		return nil, err
+	}
+
+	oraclePubKey, err := btcec.ParsePubKey(oraclePubKeyBz, btcec.S256())
+	if err != nil {
+		return nil, err
+	}
+
+	// shared key
+	sharedKey := crypto.DeriveSharedKey(privKey, oraclePubKey, crypto.KDFSHA256)
+
+	// encrypt data
+	encryptedData, err := crypto.Encrypt(sharedKey, nil, origData)
+	if err != nil {
+		return nil, err
+	}
+
+	return encryptedData, nil
+}

cmd/panacead/cmd/root.go

@@ -113,6 +113,7 @@ func initRootCmd(rootCmd *cobra.Command, encodingConfig params.EncodingConfig) {
 		debug.Cmd(),
 		// this line is used by starport scaffolding # stargate/root/commands
 		AddGenesisWasmMsgCmd(app.DefaultNodeHome),
+		EncryptDataCmd(app.DefaultNodeHome),
 	)
 
 	a := appCreator{encodingConfig}

crypto/aes256.go

@@ -0,0 +1,83 @@
+package crypto
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"crypto/sha256"
+	"fmt"
+	"io"
+
+	"github.com/btcsuite/btcd/btcec"
+)
+
+// DeriveSharedKey derives a shared key (which can be used for asymmetric encryption)
+// using a specified KDF (Key Derivation Function)
+// from a shared secret generated by Diffie-Hellman key exchange (ECDH).
+func DeriveSharedKey(priv *btcec.PrivateKey, pub *btcec.PublicKey, kdf func([]byte) []byte) []byte {
+	sharedSecret := btcec.GenerateSharedSecret(priv, pub)
+	return kdf(sharedSecret)
+}
+
+// KDFSHA256 is a key derivation function which uses SHA256.
+func KDFSHA256(in []byte) []byte {
+	out := sha256.Sum256(in)
+	return out[:]
+}
+
+// Encrypt combines secretKey and secondKey to encrypt with AES256-GCM method.
+func Encrypt(secretKey, additional, data []byte) ([]byte, error) {
+	if len(secretKey) != 32 {
+		return nil, fmt.Errorf("secret key is not for AES-256: total %d bits", 8*len(secretKey))
+	}
+
+	// prepare AES-256-GSM cipher
+	block, err := aes.NewCipher(secretKey)
+	if err != nil {
+		return nil, err
+	}
+
+	aesGCM, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, err
+	}
+
+	// make random nonce
+	nonce := make([]byte, aesGCM.NonceSize())
+	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
+		return nil, err
+	}
+
+	// encrypt data with second key
+	ciphertext := aesGCM.Seal(nonce, nonce, data, additional)
+	return ciphertext, nil
+}
+
+// Decrypt combines secretKey and secondKey to decrypt AES256-GCM.
+func Decrypt(secretKey []byte, additional []byte, ciphertext []byte) ([]byte, error) {
+	if len(secretKey) != 32 {
+		return nil, fmt.Errorf("secret key is not for AES-256: total %d bits", 8*len(secretKey))
+	}
+
+	// prepare AES-256-GCM cipher
+	block, err := aes.NewCipher(secretKey)
+	if err != nil {
+		return nil, err
+	}
+
+	aesgcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, err
+	}
+
+	nonceSize := aesgcm.NonceSize()
+	nonce, pureCiphertext := ciphertext[:nonceSize], ciphertext[nonceSize:]
+
+	// decrypt ciphertext with second key
+	plaintext, err := aesgcm.Open(nil, nonce, pureCiphertext, additional)
+	if err != nil {
+		return nil, err
+	}
+
+	return plaintext, nil
+}

crypto/aes256_test.go

@@ -0,0 +1,34 @@
+package crypto
+
+import (
+	"crypto/rand"
+	"io"
+	"testing"
+
+	"github.com/btcsuite/btcd/btcec"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDecryptWithAES256(t *testing.T) {
+	privKey1, err := btcec.NewPrivateKey(btcec.S256())
+	require.NoError(t, err)
+	privKey2, err := btcec.NewPrivateKey(btcec.S256())
+	require.NoError(t, err)
+
+	data := []byte("hello, Panacea")
+
+	shareKey1 := DeriveSharedKey(privKey1, privKey2.PubKey(), KDFSHA256)
+	shareKey2 := DeriveSharedKey(privKey2, privKey1.PubKey(), KDFSHA256)
+
+	nonce := make([]byte, 12)
+	_, err = io.ReadFull(rand.Reader, nonce)
+	require.NoError(t, err)
+
+	encryptedData, err := Encrypt(shareKey1, nonce, data)
+	require.NoError(t, err)
+
+	decryptedData, err := Decrypt(shareKey2, nonce, encryptedData)
+	require.NoError(t, err)
+
+	require.Equal(t, decryptedData, data)
+}