matrix_sdk_qrcode/
utils.rs

1// Copyright 2021 The Matrix.org Foundation C.I.C.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use qrcode::{bits::Bits, EcLevel, QrCode, Version};
16use ruma_common::serde::Base64;
17use vodozemac::Ed25519PublicKey;
18
19use crate::error::EncodingError;
20
21pub(crate) const HEADER: &[u8] = b"MATRIX";
22pub(crate) const VERSION: u8 = 0x2;
23pub(crate) const MAX_MODE: u8 = 0x2;
24pub(crate) const MIN_SECRET_LEN: usize = 8;
25
26pub(crate) fn to_bytes(
27    mode: u8,
28    flow_id: &str,
29    first_key: Ed25519PublicKey,
30    second_key: Ed25519PublicKey,
31    shared_secret: &Base64,
32) -> Result<Vec<u8>, EncodingError> {
33    let flow_id_len: u16 = flow_id.len().try_into()?;
34    let flow_id_len = flow_id_len.to_be_bytes();
35
36    let data = [
37        HEADER,
38        &[VERSION],
39        &[mode],
40        flow_id_len.as_ref(),
41        flow_id.as_bytes(),
42        first_key.as_bytes(),
43        second_key.as_bytes(),
44        shared_secret.as_bytes(),
45    ]
46    .concat();
47
48    Ok(data)
49}
50
51pub(crate) fn to_qr_code(
52    mode: u8,
53    flow_id: &str,
54    first_key: Ed25519PublicKey,
55    second_key: Ed25519PublicKey,
56    shared_secret: &Base64,
57) -> Result<QrCode, EncodingError> {
58    let data = to_bytes(mode, flow_id, first_key, second_key, shared_secret)?;
59
60    // Mobile clients seem to have trouble decoding the QR code that gets
61    // generated by `QrCode::new()` it seems to add a couple of data segments
62    // with different data modes/types. The parsers seem to assume a single
63    // data type and since we start with an ASCII `MATRIX` header the rest of
64    // the data gets treated as a string as well.
65    //
66    // We make sure that there isn't an ECI bit set and we just push the bytes,
67    // this seems to help since the decoder doesn't assume an encoding and
68    // treats everything as raw bytes.
69    let mut bits = Bits::new(Version::Normal(7));
70    bits.push_byte_data(&data)?;
71    bits.push_terminator(EcLevel::L)?;
72
73    Ok(QrCode::with_bits(bits, EcLevel::L)?)
74}
matrix_sdk_qrcode/utils.rs

matrix_sdk_qrcode/
utils.rs
