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feat: 🎸 Add support for decrypting messages from ios using v1 protocol #19

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Merged
highesttt merged 1 commit into from
Jan 20, 2026
Merged

feat: 🎸 Add support for decrypting messages from ios using v1 protocol #19

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38 changes: 38 additions & 0 deletions pkg/e2ee/manager.go
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Original file line number Diff line number Diff line change
Expand Up @@ -329,13 +329,51 @@ func (m *Manager) DecryptMessageV2(msg *line.Message) (string, error) {
if err != nil {
return "", err
}

ver := 2
if vStr, ok := msg.ContentMetadata["e2eeVersion"]; ok && vStr == "1" {
ver = 1
}

if ver == 1 {
cipher, err := assembleCipherV1(msg.Chunks)

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The variable 'cipher' is assigned on line 324 from assembleCipher(msg.Chunks) but then shadowed on line 339 within the v1 block by declaring a new cipher variable with assembleCipherV1(msg.Chunks). This creates unnecessary confusion and wastes the initial computation. The first cipher assignment should be moved inside the 'else' or 'if ver == 2' block to avoid this shadowing and unnecessary computation when ver is 1.

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if err != nil {
return "", err
}
pt, _, err := m.runner.ChannelDecryptV1(chanID, senderKeyID, receiverKeyID, base64.StdEncoding.EncodeToString(cipher))
if err != nil {
return "", err
}
return pt, nil
}

pt, _, err := m.runner.ChannelDecryptV2(chanID, msg.To, msg.From, senderKeyID, receiverKeyID, msg.ContentType, base64.StdEncoding.EncodeToString(cipher))
if err != nil {
return "", err
}
return pt, nil
}

func assembleCipherV1(chunks []string) ([]byte, error) {
if len(chunks) < 3 {
return nil, fmt.Errorf("not enough chunks")
}
decode := func(s string) ([]byte, error) { return base64.StdEncoding.DecodeString(strings.TrimSpace(s)) }
b0, err := decode(chunks[0])
if err != nil {
return nil, err
}
b1, err := decode(chunks[1])
if err != nil {
return nil, err
}
b2, err := decode(chunks[2])
if err != nil {
return nil, err
}
return append(append(b0, b1...), b2...), nil
Comment on lines +357 to +374

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The assembleCipherV1 function concatenates chunks in the order [first, middle, tag] which differs from assembleCipher (v2) that reorders them to [first, tag, middle] as noted in its comment. Please verify that this difference in chunk ordering is intentional for the v1 protocol. If this is intentional, consider adding a comment explaining the chunk order for v1, similar to the comment in assembleCipher.

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}

func (m *Manager) UnwrapGroupSharedKey(chatMid string, sharedKey *line.E2EEGroupSharedKey) (int, error) {
m.mu.Lock()
defer m.mu.Unlock()
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15 changes: 15 additions & 0 deletions pkg/internal/runner.js
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Expand Up @@ -398,6 +398,21 @@ async function run() {
process.stdout.write(
JSON.stringify({ ciphertext: u8ToB64(ct) }) + "\n"
);
} else if (type === "channel_decrypt_v1") { // messages sent from ios LINE app use v1

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The inline comment should capitalize "iOS" as it's a proper noun. It should read: "messages sent from iOS LINE app use v1"

Suggested change
} else if (type === "channel_decrypt_v1") { // messages sent from ios LINE app use v1
} else if (type === "channel_decrypt_v1") { // messages sent from iOS LINE app use v1

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const {
channelId,
ciphertext,
} = query;
Comment on lines +402 to +405

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The senderKeyId and receiverKeyId parameters are extracted from the query but never used. If these parameters are not needed for v1 decryption, they should be removed from the query destructuring. If they are needed, they should be passed to the decryptV1 method or validated.

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const chan = getChannel(toIntStrict("channelId", channelId));

const u8Cipher = b64ToU8(ciphertext);
const pt = chan.decryptV1(
u8Cipher
);
const plaintext = new TextDecoder().decode(Uint8Array.from(pt).buffer);
process.stdout.write(
JSON.stringify({ plaintext, base64: u8ToB64(pt) }) + "\n"
);
} else if (type === "channel_decrypt_v2") {
const {
channelId,
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22 changes: 22 additions & 0 deletions pkg/runner.go
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Expand Up @@ -404,6 +404,28 @@ func (r *Runner) ChannelEncryptV2(channelID int, to, from string, senderKeyID, r
return ct, nil
}

// decrypts ciphertext with channel v1 (ios)

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The comment should follow Go documentation conventions. It should start with the function name and use proper capitalization: "ChannelDecryptV1 decrypts ciphertext with channel v1 (iOS)." Note that "iOS" should be capitalized as it's a proper noun.

Suggested change
// decrypts ciphertext with channel v1 (ios)
// ChannelDecryptV1 decrypts ciphertext with channel v1 (iOS).

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func (r *Runner) ChannelDecryptV1(channelID, senderKeyID, receiverKeyID int, ciphertext string) (string, string, error) {
resp, err := r.call(map[string]any{
"type": "channel_decrypt_v1",
"channelId": channelID,
"senderKeyId": senderKeyID,
"receiverKeyId": receiverKeyID,
"ciphertext": ciphertext,
})
if err != nil {
return "", "", err
}
var plaintext, base64 string
if v, ok := resp["plaintext"]; ok {
_ = json.Unmarshal(v, &plaintext)
}
if v, ok := resp["base64"]; ok {
_ = json.Unmarshal(v, &base64)
}
return plaintext, base64, nil
}

// decrypts ciphertext with channel v2
func (r *Runner) ChannelDecryptV2(channelID int, to, from string, senderKeyID, receiverKeyID, contentType int, ciphertext string) (string, string, error) {
resp, err := r.call(map[string]any{
Expand Down
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