Switched encryption of payload and keys to AES

Added Encrypted field to the protobuf

protocol/common/crypto.go

@@ -9,11 +9,17 @@ import (
 
 	"golang.org/x/crypto/sha3"
 
+	"github.com/ethereum/go-ethereum/crypto/ecies"
+
 	"github.com/status-im/status-go/eth-node/crypto"
 	"github.com/status-im/status-go/eth-node/types"
 )
 
-const nonceLength = 12
+const(
+	nonceLength = 12
+	defaultECHDSharedKeyLength = 16
+	defaultECHDMACLength = 16
+)
 
 var ErrInvalidCiphertextLength = errors.New("invalid cyphertext length")
 
@@ -86,3 +92,11 @@ func HexToPubkey(pk string) (*ecdsa.PublicKey, error) {
 	}
 	return crypto.UnmarshalPubkey(bytes)
 }
+
+func MakeECDHSharedKey(yourPrivateKey *ecdsa.PrivateKey, theirPubKey *ecdsa.PublicKey) ([]byte, error) {
+	return ecies.ImportECDSA(yourPrivateKey).GenerateShared(
+		ecies.ImportECDSAPublic(theirPubKey),
+		defaultECHDSharedKeyLength,
+		defaultECHDMACLength,
+	)
+}

protocol/messenger.go

@@ -5,7 +5,6 @@ import (
 	"context"
 	"crypto/ecdsa"
 	crand "crypto/rand"
-	"crypto/x509"
 	"database/sql"
 	"encoding/hex"
 	"fmt"
@@ -23,8 +22,6 @@ import (
 	"github.com/davecgh/go-spew/spew"
 	"github.com/golang/protobuf/proto"
 
-	"github.com/ethereum/go-ethereum/crypto/ecies"
-
 	"github.com/status-im/status-go/appdatabase"
 	"github.com/status-im/status-go/appmetrics"
 	"github.com/status-im/status-go/connection"
@@ -780,6 +777,7 @@ func (m *Messenger) attachIdentityImagesToChatIdentity(context chatContext, ci *
 		return err
 	}
 
+	// TODO remove the use of ProfilePicturesVisibility and create a new settings field,
 	if s.ProfilePicturesVisibility == accounts.ProfilePicturesVisibilityNone {
 		m.logger.Info(fmt.Sprintf("settings.ProfilePicturesVisibility is set to '%d', skipping attaching IdentityImages", s.ProfilePicturesVisibility))
 		return nil
@@ -832,46 +830,95 @@ func (m *Messenger) attachIdentityImagesToChatIdentity(context chatContext, ci *
 	return nil
 }
 
-func (m *Messenger) encryptIdentityImagesWithContactPubKeys(ciis map[string]*protobuf.IdentityImage) error {
+func (m *Messenger) encryptIdentityImagesWithContactPubKeys(iis map[string]*protobuf.IdentityImage) (err error) {
-	// Make ephemeral key
+	// Make AES key
-	pk, err := crypto.GenerateKey()
+	AESKey := make([]byte, 32)
+	_, err = crand.Read(AESKey)
 	if err != nil {
 		return err
 	}
 
-	// Marshal the ephemeral private key into bytes
+	for _, ii := range iis {
-	mpk, err := x509.MarshalECPrivateKey(pk)
+		// Encrypt image payload with the AES key
-	if err != nil {
+		encryptedPayload, err := common.Encrypt(ii.Payload, AESKey, crand.Reader)
-		return err
-	}
-
-	for _, ii := range ciis {
-		// Encrypt image payloads with the ephemeral public key
-		encryptedPayload, err := ecies.Encrypt(crand.Reader, ecies.ImportECDSAPublic(&pk.PublicKey), ii.Payload, nil, nil)
 		if err != nil {
 			return err
 		}
 
 		// Overwrite the unencrypted payload with the newly encrypted payload
 		ii.Payload = encryptedPayload
-		for _, c := range m.allContacts {
+		ii.Encrypted = true
+		m.allContacts.Range(func(contactID string, c *Contact) (shouldContinue bool) {
 			if !c.IsAdded() {
-				continue
+				return false
 			}
 
 			pubK, err := c.PublicKey()
 			if err != nil {
-				return err
+				return false
+			}
+			// Generate a Diffie-Helman (DH) between the sender private key and the recipient's public key
+			sharedKey, err := common.MakeECDHSharedKey(m.identity, pubK)
+			if err != nil {
+				return false
 			}
 
-			// Encrypt the marshalled ephemeral private key with the contact's public key
+			// Encrypt the main AES key with AES encryption using the DH key
-			empk, err := ecies.Encrypt(crand.Reader, ecies.ImportECDSAPublic(pubK), mpk, nil, nil)
+			eAESKey, err := common.Encrypt(AESKey, sharedKey, crand.Reader)
+			if err != nil {
+				return false
+			}
+
+			// Append the the encrypted main AES key to the IdentityImage's EncryptionKeys slice.
+			ii.EncryptionKeys = append(ii.EncryptionKeys, eAESKey)
+
+			return true
+		})
+
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (m *Messenger) decryptIdentityImagesWithIdentityPrivateKey(iis map[string]*protobuf.IdentityImage, senderPubKey *ecdsa.PublicKey) error {
+image:
+	for _, ii := range iis {
+		for _, empk := range ii.EncryptionKeys {
+			// Generate a Diffie-Helman (DH) between the recipient's private key and the sender's public key
+			sharedKey, err := common.MakeECDHSharedKey(m.identity, senderPubKey)
 			if err != nil {
 				return err
 			}
 
-			// Append the the encrypted private key to the IdentityImage's EncryptionKeys slice.
+			// Decrypt the main encryption AES key with AES encryption using the DH key
-			ii.EncryptionKeys = append(ii.EncryptionKeys, empk)
+			dAESKey, err := common.Decrypt(empk, sharedKey)
+			if err != nil {
+				if err.Error() == "cipher: message authentication failed" {
+					continue
+				}
+				return err
+			}
+			if dAESKey == nil{
+				return errors.New("decrypting the payload encryption key resulted in no error and a nil key")
+			}
+
+			// Decrypt the payload with the newly decrypted main encryption AES key
+			payload, err := common.Decrypt(ii.Payload, dAESKey)
+			if err != nil {
+				return err
+			}
+			if payload == nil {
+				// TODO should this be a logger warn? A payload could theoretically be validly empty
+				return errors.New("decrypting the payload resulted in no error and a nil payload")
+			}
+
+			// Overwrite the payload with the decrypted data
+			ii.Payload = payload
+			ii.Encrypted = false // TODO handle the encryption state in the consuming code
+			continue image
 		}
 	}
 

protocol/messenger_maps.go

@@ -79,6 +79,16 @@ func (cm *contactMap) Delete(contactID string) {
 	cm.sm.Delete(contactID)
 }
 
+func (cm *contactMap) Len() int {
+	count := 0
+	cm.Range(func(key string, value *Contact) (shouldContinue bool) {
+		count++
+		return true
+	})
+
+	return count
+}
+
 /*
 |--------------------------------------------------------------------------
 | systemMessageTranslationsMap

protocol/messenger_test.go

@@ -2564,3 +2564,81 @@ func (s *MessengerSuite) TestPublicMessageOnCommunityChat() {
 	s.Require().Error(err)
 	s.Require().Equal(ErrMessageForWrongChatType, err)
 }
+
+func (s *MessengerSuite) TestEncryptDecryptIdentityImagesWithContactPubKeys() {
+	smPayload := "hello small image"
+	lgPayload := "hello large image"
+
+	ci := protobuf.ChatIdentity{
+		Clock:  uint64(time.Now().Unix()),
+		Images: map[string]*protobuf.IdentityImage{
+			"small": {
+				Payload: []byte(smPayload),
+			},
+			"large": {
+				Payload: []byte(lgPayload),
+			},
+		},
+	}
+
+	// Make contact keys and Contacts, set the Contacts to added
+	var contactKeys []*ecdsa.PrivateKey
+	for i:=0; i < 10; i++ {
+		contactKey, err := crypto.GenerateKey()
+		s.Require().NoError(err)
+		contactKeys = append(contactKeys, contactKey)
+
+		contact, err := BuildContactFromPublicKey(&contactKey.PublicKey)
+		s.Require().NoError(err)
+
+		contact.SystemTags = append(contact.SystemTags, contactAdded)
+		s.m.allContacts.Store(contact.ID, contact)
+	}
+
+	// Test encryptIdentityImagesWithContactPubKeys
+	err := s.m.encryptIdentityImagesWithContactPubKeys(ci.Images)
+	s.Require().NoError(err)
+
+	for _, ii := range ci.Images {
+		s.Require().Equal(s.m.allContacts.Len, len(ii.EncryptionKeys))
+	}
+	s.Require().NotEqual([]byte(smPayload), ci.Images["small"].Payload)
+	s.Require().NotEqual([]byte(lgPayload), ci.Images["large"].Payload)
+
+	// Switch messenger identities
+	sender := s.m.identity
+	s.m.identity = contactKeys[2]
+
+	// Test decryptIdentityImagesWithIdentityPrivateKey
+	err = s.m.decryptIdentityImagesWithIdentityPrivateKey(ci.Images, &sender.PublicKey)
+	s.Require().NoError(err)
+
+	s.Require().Equal(smPayload, string(ci.Images["small"].Payload))
+	s.Require().Equal(lgPayload, string(ci.Images["large"].Payload))
+
+	// RESET Messenger identity, Contacts and IdentityImage.EncryptionKeys
+	s.m.identity = sender
+	s.m.allContacts = nil
+	ci.Images["small"].EncryptionKeys = nil
+	ci.Images["large"].EncryptionKeys = nil
+
+	// Test encryptIdentityImagesWithContactPubKeys with no contacts
+	err = s.m.encryptIdentityImagesWithContactPubKeys(ci.Images)
+	s.Require().NoError(err)
+
+	for _, ii := range ci.Images {
+		s.Require().Equal(0, len(ii.EncryptionKeys))
+	}
+	s.Require().NotEqual([]byte(smPayload), ci.Images["small"].Payload)
+	s.Require().NotEqual([]byte(lgPayload), ci.Images["large"].Payload)
+
+	// Switch messenger identities
+	s.m.identity = contactKeys[2]
+
+	// Test decryptIdentityImagesWithIdentityPrivateKey with no valid identity
+	err = s.m.decryptIdentityImagesWithIdentityPrivateKey(ci.Images, &sender.PublicKey)
+	s.Require().NoError(err)
+
+	s.Require().NotEqual([]byte(smPayload), ci.Images["small"].Payload)
+	s.Require().NotEqual([]byte(lgPayload), ci.Images["large"].Payload)
+}

protocol/protobuf/chat_identity.pb.go

@@ -150,6 +150,8 @@ type IdentityImage struct {
 	ImageType ImageType `protobuf:"varint,3,opt,name=image_type,json=imageType,proto3,enum=protobuf.ImageType" json:"image_type,omitempty"`
 	// encryption_keys is a list of encrypted keys that can be used to decrypted an encrypted payload
 	EncryptionKeys [][]byte `protobuf:"bytes,4,rep,name=encryption_keys,json=encryptionKeys,proto3" json:"encryption_keys,omitempty"`
+	// encrypted signals the encryption state of the payload, default is false.
+	Encrypted            bool     `protobuf:"varint,5,opt,name=encrypted,proto3" json:"encrypted,omitempty"`
 	XXX_NoUnkeyedLiteral struct{} `json:"-"`
 	XXX_unrecognized     []byte   `json:"-"`
 	XXX_sizecache        int32    `json:"-"`
@@ -208,6 +210,13 @@ func (m *IdentityImage) GetEncryptionKeys() [][]byte {
 	return nil
 }
 
+func (m *IdentityImage) GetEncrypted() bool {
+	if m != nil {
+		return m.Encrypted
+	}
+	return false
+}
+
 func init() {
 	proto.RegisterEnum("protobuf.IdentityImage_SourceType", IdentityImage_SourceType_name, IdentityImage_SourceType_value)
 	proto.RegisterType((*ChatIdentity)(nil), "protobuf.ChatIdentity")
@@ -220,31 +229,32 @@ func init() {
 }
 
 var fileDescriptor_7a652489000a5879 = []byte{
-	// 414 bytes of a gzipped FileDescriptorProto
+	// 425 bytes of a gzipped FileDescriptorProto
-	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x54, 0x90, 0xdf, 0x6e, 0xd3, 0x30,
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x54, 0x90, 0xc1, 0x6e, 0xd3, 0x40,
-	0x14, 0xc6, 0x49, 0xd2, 0x76, 0xeb, 0x71, 0xd7, 0x55, 0x2e, 0xd2, 0xc2, 0xae, 0x42, 0x6f, 0xe8,
+	0x10, 0x86, 0xb1, 0x9d, 0xa4, 0xc9, 0x6c, 0x9a, 0x46, 0x1b, 0xa4, 0x9a, 0x8a, 0x83, 0xc9, 0x85,
-	0x0d, 0x41, 0x2a, 0x37, 0x68, 0x5c, 0x85, 0x52, 0xa4, 0x69, 0x28, 0x9d, 0xdc, 0x8e, 0x69, 0xdc,
+	0x5c, 0x30, 0x52, 0xb8, 0xa0, 0x72, 0x32, 0x21, 0x48, 0x55, 0x91, 0x53, 0x6d, 0x52, 0xaa, 0x72,
-	0x58, 0x5e, 0x6a, 0x58, 0xd4, 0xd4, 0x8e, 0x62, 0x17, 0xc9, 0xcf, 0xc1, 0x5b, 0xf0, 0x94, 0x68,
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-	0x76, 0xb3, 0xa4, 0x57, 0x3e, 0x7f, 0xbe, 0xf3, 0x3b, 0x9f, 0x0f, 0x8c, 0xb3, 0x27, 0xa6, 0x69,
+	0x67, 0x6d, 0xec, 0x9e, 0x76, 0xe6, 0x9f, 0x99, 0x6f, 0xfe, 0x1d, 0x98, 0xc5, 0x8f, 0x5c, 0x45,
-	0xbe, 0xe1, 0x42, 0xe7, 0xda, 0xc4, 0x65, 0x25, 0xb5, 0xc4, 0xa7, 0xf6, 0x79, 0xdc, 0xff, 0xba,
+	0x69, 0x22, 0x72, 0x95, 0x2a, 0xed, 0x97, 0x55, 0xa1, 0x0a, 0x3a, 0xc4, 0xe7, 0xe1, 0xf8, 0xf3,
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+	0x82, 0x88, 0xfc, 0x78, 0x90, 0x46, 0x9e, 0xff, 0xb1, 0x61, 0xbc, 0x7a, 0xe4, 0xea, 0xaa, 0xee,
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-	0xa7, 0x5c, 0x28, 0x2a, 0xd8, 0x8e, 0x87, 0x7e, 0xe4, 0x4d, 0xfb, 0xe4, 0x84, 0x0b, 0x95, 0xb2,
+	0x18, 0x8a, 0x5c, 0x46, 0x39, 0x3f, 0x08, 0xd7, 0xf6, 0xac, 0xc5, 0x88, 0x9d, 0x88, 0x5c, 0x86,
-	0x1d, 0xc7, 0x57, 0xd0, 0xcb, 0x77, 0xec, 0x37, 0x57, 0x61, 0x10, 0x05, 0x53, 0x34, 0x9b, 0xc4,
+	0xfc, 0x20, 0xe8, 0x25, 0x0c, 0xd2, 0x03, 0xff, 0x25, 0xa4, 0xeb, 0x78, 0xce, 0x82, 0x2c, 0xe7,
-	0xf5, 0xa6, 0xb8, 0x0d, 0x8e, 0xaf, 0xad, 0x68, 0x21, 0x74, 0x65, 0xc8, 0x61, 0x02, 0xbf, 0x85,
+	0x7e, 0xb3, 0xc9, 0xef, 0x82, 0xfd, 0x2b, 0x6c, 0x5a, 0xe7, 0xaa, 0xd2, 0xac, 0x9e, 0xa0, 0x6f,
-	0xc1, 0x26, 0x57, 0x65, 0xc1, 0x8c, 0x43, 0x77, 0x2c, 0x1a, 0x1d, 0x6a, 0x16, 0x1f, 0x01, 0xda,
+	0x60, 0x9c, 0xa4, 0xb2, 0xcc, 0xb8, 0x36, 0xe8, 0x1e, 0xa2, 0x49, 0xad, 0x21, 0xde, 0x03, 0x92,
-	0x70, 0x95, 0x55, 0x79, 0xa9, 0x73, 0x29, 0xc2, 0xee, 0x41, 0xd1, 0x94, 0xac, 0x63, 0x59, 0xc8,
+	0x08, 0x19, 0x57, 0x69, 0xa9, 0xd2, 0x22, 0x77, 0xfb, 0x75, 0x47, 0x2b, 0xa1, 0xe3, 0x22, 0x2b,
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+	0x2a, 0x77, 0x80, 0x35, 0x93, 0x5c, 0x30, 0x20, 0x9d, 0x8d, 0x74, 0x0a, 0xce, 0x5e, 0x68, 0xfc,
-	0x54, 0x9f, 0x3c, 0x87, 0xf8, 0x3d, 0x74, 0xff, 0xb0, 0x62, 0xef, 0xfe, 0x83, 0x66, 0x17, 0x8d,
+	0xd4, 0x88, 0x3d, 0x85, 0xf4, 0x1d, 0xf4, 0x7f, 0xf3, 0xec, 0x68, 0xfe, 0x43, 0x96, 0xe7, 0xad,
-	0xed, 0xda, 0xb2, 0x9d, 0x27, 0x4e, 0x75, 0xe5, 0x7f, 0xf2, 0x26, 0x7f, 0x7d, 0x38, 0x3b, 0x6a,
+	0xed, 0xc6, 0x32, 0xce, 0x33, 0xd3, 0x75, 0x69, 0x7f, 0xb4, 0xe6, 0x7f, 0x6d, 0x38, 0x7d, 0x56,
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+	0xa4, 0x2e, 0x9c, 0x94, 0x5c, 0x67, 0x05, 0x4f, 0x10, 0x3d, 0x66, 0x4d, 0x4a, 0x57, 0x40, 0x64,
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+	0x71, 0xac, 0x62, 0x11, 0x29, 0x5d, 0x9a, 0x25, 0x93, 0xee, 0x6d, 0x9e, 0x71, 0xfc, 0x2d, 0xb6,
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+	0xee, 0x74, 0x29, 0x18, 0xc8, 0xff, 0x31, 0x5d, 0x02, 0xe0, 0xa5, 0x0c, 0xc3, 0x41, 0xc6, 0xac,
-	0x31, 0x9e, 0x7b, 0x76, 0xa8, 0x9f, 0xd7, 0x21, 0x7e, 0x07, 0xe7, 0x5c, 0x64, 0x95, 0xb1, 0xc7,
+	0xc3, 0x78, 0xaa, 0xe1, 0xd0, 0x28, 0x6d, 0x42, 0xfa, 0x16, 0xce, 0x44, 0x1e, 0x57, 0x1a, 0x8f,
-	0xa1, 0x5b, 0x6e, 0x54, 0xd8, 0x89, 0x82, 0xe9, 0x80, 0x0c, 0x9b, 0xf2, 0x0d, 0x37, 0x6a, 0xf2,
+	0x13, 0xed, 0x85, 0x96, 0x6e, 0xcf, 0x73, 0x16, 0x63, 0x36, 0x69, 0xe5, 0x6b, 0xa1, 0x25, 0x7d,
-	0x0d, 0xa0, 0x59, 0x8b, 0x2f, 0x60, 0x7c, 0x97, 0xde, 0xa4, 0xcb, 0xfb, 0x94, 0xae, 0x96, 0x77,
+	0x0d, 0xa3, 0x5a, 0x11, 0x09, 0xde, 0x75, 0xc8, 0x5a, 0x61, 0xfe, 0x15, 0xa0, 0x35, 0x45, 0xcf,
-	0x64, 0xbe, 0xa0, 0xeb, 0x87, 0xdb, 0xc5, 0xe8, 0x15, 0x3e, 0x07, 0x44, 0x92, 0x7b, 0x7a, 0x9b,
+	0x61, 0x76, 0x1b, 0x5e, 0x87, 0x9b, 0xbb, 0x30, 0xda, 0x6e, 0x6e, 0xd9, 0x6a, 0x1d, 0xed, 0xee,
-	0x3c, 0x7c, 0x5f, 0x26, 0x5f, 0x47, 0x1e, 0x1e, 0x02, 0x2c, 0xd2, 0x15, 0x4d, 0x7e, 0x24, 0xeb,
+	0x6f, 0xd6, 0xd3, 0x17, 0xf4, 0x0c, 0x08, 0x0b, 0xee, 0xa2, 0x9b, 0xe0, 0xfe, 0xdb, 0x26, 0xf8,
-	0x84, 0x8c, 0xfc, 0x2f, 0x67, 0x3f, 0x51, 0xfc, 0xe1, 0x73, 0x6d, 0xea, 0xb1, 0x67, 0xa3, 0x8f,
+	0x32, 0xb5, 0xe8, 0x04, 0x60, 0x1d, 0x6e, 0xa3, 0xe0, 0x7b, 0xb0, 0x0b, 0xd8, 0xd4, 0xfe, 0x7c,
-	0xff, 0x03, 0x00, 0x00, 0xff, 0xff, 0x8e, 0x12, 0x2e, 0x02, 0x86, 0x02, 0x00, 0x00,
+	0xfa, 0x83, 0xf8, 0xef, 0x3f, 0x35, 0x96, 0x1f, 0x06, 0x18, 0x7d, 0xf8, 0x17, 0x00, 0x00, 0xff,
+	0xff, 0xc9, 0xd1, 0xd6, 0xde, 0xa4, 0x02, 0x00, 0x00,
 }

protocol/protobuf/chat_identity.proto

@@ -41,6 +41,9 @@ message IdentityImage {
   // encryption_keys is a list of encrypted keys that can be used to decrypted an encrypted payload
   repeated bytes encryption_keys = 4;
 
+  // encrypted signals the encryption state of the payload, default is false.
+  bool encrypted = 5;
+
   // SourceType are the predefined types of image source allowed
   enum SourceType {
     UNKNOWN_SOURCE_TYPE = 0;