.idea/lib_um_crypto.iml

@@ -10,7 +10,6 @@
       <sourceFolder url="file://$MODULE_DIR$/um_crypto/utils/src" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/um_crypto/ncm/src" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/um_audio/src" isTestSource="false" />
-      <sourceFolder url="file://$MODULE_DIR$/um_crypto/kgm/src" isTestSource="false" />
       <excludeFolder url="file://$MODULE_DIR$/target" />
       <excludeFolder url="file://$MODULE_DIR$/um_wasm_loader/dist" />
       <excludeFolder url="file://$MODULE_DIR$/um_wasm_loader/pkg" />

Cargo.lock

@@ -74,15 +74,6 @@ version = "0.22.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "72b3254f16251a8381aa12e40e3c4d2f0199f8c6508fbecb9d91f575e0fbb8c6"
 
-[[package]]
-name = "block-buffer"
-version = "0.10.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3078c7629b62d3f0439517fa394996acacc5cbc91c5a20d8c658e77abd503a71"
-dependencies = [
- "generic-array",
-]
-
 [[package]]
 name = "block-padding"
 version = "0.3.3"
@@ -225,16 +216,6 @@ version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "56254986775e3233ffa9c4d7d3faaf6d36a2c09d30b20687e9f88bc8bafc16c8"
 
-[[package]]
-name = "digest"
-version = "0.10.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9ed9a281f7bc9b7576e61468ba615a66a5c8cfdff42420a70aa82701a3b1e292"
-dependencies = [
- "block-buffer",
- "crypto-common",
-]
-
 [[package]]
 name = "either"
 version = "1.13.0"
@@ -322,16 +303,6 @@ version = "0.4.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a7a70ba024b9dc04c27ea2f0c0548feb474ec5c54bba33a7f72f873a39d07b24"
 
-[[package]]
-name = "md-5"
-version = "0.10.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d89e7ee0cfbedfc4da3340218492196241d89eefb6dab27de5df917a6d2e78cf"
-dependencies = [
- "cfg-if",
- "digest",
-]
-
 [[package]]
 name = "minicov"
 version = "0.3.5"
@@ -470,7 +441,6 @@ version = "0.1.0"
 dependencies = [
  "anyhow",
  "clap",
- "umc_kgm",
  "umc_kuwo",
  "umc_ncm",
  "umc_qmc",
@@ -492,16 +462,6 @@ dependencies = [
  "wasm-bindgen-test",
 ]
 
-[[package]]
-name = "umc_kgm"
-version = "0.1.0"
-dependencies = [
- "byteorder",
- "itertools",
- "thiserror",
- "umc_utils",
-]
-
 [[package]]
 name = "umc_kuwo"
 version = "0.1.0"
@@ -547,8 +507,6 @@ name = "umc_utils"
 version = "0.1.0"
 dependencies = [
  "base64",
- "itertools",
- "md-5",
 ]
 
 [[package]]

um_cli/Cargo.toml

@@ -7,7 +7,6 @@ edition = "2021"
 anyhow = "1.0.86"
 clap = { version = "4.5.17", features = ["derive"] }
 umc_kuwo = { path = "../um_crypto/kuwo" }
-umc_kgm = { path = "../um_crypto/kgm" }
-umc_ncm = { path = "../um_crypto/ncm" }
 umc_qmc = { path = "../um_crypto/qmc" }
+umc_ncm = { path = "../um_crypto/ncm" }
 umc_utils = { path = "../um_crypto/utils" }

um_cli/src/cmd/kgm.rs

@@ -1,44 +0,0 @@
-use crate::Cli;
-use clap::Args;
-use std::fs::File;
-use std::io::{Read, Seek, SeekFrom, Write};
-use std::path::PathBuf;
-use umc_kgm::header::Header;
-
-/// Decrypt a KGM/VPR file (Kugou Music)
-#[derive(Args)]
-pub struct ArgsKGM {
-    /// Path to output file, e.g. /export/Music/song.flac
-    #[arg(short, long)]
-    output: PathBuf,
-
-    /// Path to input file, e.g. /export/Music/song.kgm
-    #[arg(name = "input")]
-    input: PathBuf,
-}
-
-impl ArgsKGM {
-    pub fn run(&self, cli: &Cli) -> anyhow::Result<i32> {
-        let mut file_input = File::open(&self.input)?;
-        let mut header = [0u8; 0x40];
-        file_input.read_exact(&mut header)?;
-        let kgm_header = Header::from_buffer(&mut header)?;
-        let decipher = kgm_header.make_decipher()?;
-        file_input.seek(SeekFrom::Start(kgm_header.offset_to_data as u64))?;
-
-        let mut offset = 0usize;
-        let mut buffer = vec![0u8; cli.buffer_size].into_boxed_slice();
-        let mut file_output = File::create(&self.output)?;
-        while let Ok(n) = file_input.read(&mut buffer) {
-            if n == 0 {
-                break;
-            }
-
-            decipher.decrypt(&mut buffer[..n], offset);
-            file_output.write_all(&buffer[..n])?;
-            offset += n;
-        }
-
-        Ok(0)
-    }
-}

um_cli/src/cmd/mod.rs

@@ -1,6 +1,5 @@
 use clap::Subcommand;
 
-pub mod kgm;
 pub mod ncm;
 pub mod qmc1;
 pub mod qmc2;
@@ -13,6 +12,4 @@ pub enum Commands {
     QMCv2(qmc2::ArgsQMCv2),
     #[command(name = "ncm")]
     NCM(ncm::ArgsNCM),
-    #[command(name = "kgm")]
-    KGM(kgm::ArgsKGM),
 }

um_cli/src/cmd/qmc2.rs

@@ -30,7 +30,7 @@ pub struct ArgsQMCv2 {
     info_only: bool,
 }
 
-fn read_ekey(ekey: &str) -> Result<Vec<u8>> {
+fn read_ekey(ekey: &str) -> Result<Box<[u8]>> {
     let mut external_file = false;
     let mut decrypt_ekey = true;
 
@@ -54,7 +54,7 @@ fn read_ekey(ekey: &str) -> Result<Vec<u8>> {
     let ekey = ekey.trim();
     let ekey = match decrypt_ekey {
         true => umc_qmc::ekey::decrypt(ekey)?,
-        false => base64::decode(ekey)?,
+        false => base64::decode(ekey)?.into_boxed_slice(),
     };
     Ok(ekey)
 }

um_cli/src/main.rs

@@ -30,7 +30,6 @@ fn run_command(cli: &Cli) -> Result<i32> {
         Some(Commands::QMCv1(cmd)) => cmd.run(&cli),
         Some(Commands::QMCv2(cmd)) => cmd.run(&cli),
         Some(Commands::NCM(cmd)) => cmd.run(&cli),
-        Some(Commands::KGM(cmd)) => cmd.run(&cli),
         None => {
             // https://github.com/clap-rs/clap/issues/3857#issuecomment-1161796261
             todo!("implement a sensible default command, similar to um/cli");

um_crypto/kgm/Cargo.toml

@@ -1,10 +0,0 @@
-[package]
-name = "umc_kgm"
-version = "0.1.0"
-edition = "2021"
-
-[dependencies]
-byteorder = "1.5.0"
-itertools = "0.13.0"
-thiserror = "1.0.63"
-umc_utils = { path = "../utils" }

um_crypto/kgm/src/header.rs

@@ -1,59 +0,0 @@
-use crate::v2::DecipherV2;
-use crate::v3::DecipherV3;
-use crate::{Decipher, KugouError};
-use byteorder::{ByteOrder, LE};
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub struct Header {
-    pub magic: [u8; 0x10],
-    pub offset_to_data: usize,
-    pub crypto_version: u32,
-    pub key_slot: u32,
-    pub decrypt_test_data: [u8; 0x10],
-    pub file_key: [u8; 0x10],
-}
-
-impl Header {
-    pub fn from_buffer<T>(buffer: T) -> Result<Self, KugouError>
-    where
-        T: AsRef<[u8]>,
-    {
-        let buffer = buffer.as_ref();
-        if buffer.len() < 0x3c {
-            Err(KugouError::HeaderTooSmall(0x3c))?;
-        }
-
-        let mut magic = [0u8; 0x10];
-        magic.copy_from_slice(&buffer[..0x10]);
-        let offset_to_data = LE::read_u32(&buffer[0x10..0x14]) as usize;
-        let crypto_version = LE::read_u32(&buffer[0x14..0x18]);
-        let key_slot = LE::read_u32(&buffer[0x18..0x1C]);
-        let mut decrypt_test_data = [0u8; 0x10];
-        decrypt_test_data.copy_from_slice(&buffer[0x1c..0x2c]);
-        let mut file_key = [0u8; 0x10];
-        file_key.copy_from_slice(&buffer[0x2c..0x3c]);
-
-        Ok(Self {
-            magic,
-            offset_to_data,
-            crypto_version,
-            key_slot,
-            decrypt_test_data,
-            file_key,
-        })
-    }
-
-    pub fn make_decipher(&self) -> Result<Box<dyn Decipher>, KugouError> {
-        let slot_key: &[u8] = match self.key_slot {
-            1 => b"l,/'",
-            slot => Err(KugouError::UnsupportedKeySlot(slot))?,
-        };
-
-        let decipher: Box<dyn Decipher> = match self.crypto_version {
-            2 => Box::from(DecipherV2::new(self, slot_key)?),
-            3 => Box::from(DecipherV3::new(self, slot_key)?),
-            version => Err(KugouError::UnsupportedCipherVersion(version))?,
-        };
-        Ok(decipher)
-    }
-}

um_crypto/kgm/src/lib.rs

@@ -1,21 +0,0 @@
-pub mod header;
-pub mod v2;
-mod v3;
-
-use thiserror::Error;
-
-#[derive(Debug, Error)]
-pub enum KugouError {
-    #[error("Header too small, need at least {0} bytes.")]
-    HeaderTooSmall(usize),
-
-    #[error("Unsupported key slot: {0}")]
-    UnsupportedKeySlot(u32),
-
-    #[error("Unsupported cipher version: {0}")]
-    UnsupportedCipherVersion(u32),
-}
-
-pub trait Decipher {
-    fn decrypt(&self, buffer: &mut [u8], offset: usize);
-}

um_crypto/kgm/src/v2.rs

@@ -1,31 +0,0 @@
-use crate::header::Header;
-use crate::{Decipher, KugouError};
-
-pub struct DecipherV2 {
-    key: [u8; 4],
-}
-
-impl DecipherV2 {
-    pub fn new(_header: &Header, slot_key: &[u8]) -> Result<Self, KugouError> {
-        let mut key = [0u8; 4];
-        key.copy_from_slice(slot_key);
-        Ok(Self { key })
-    }
-}
-
-impl Decipher for DecipherV2 {
-    fn decrypt(&self, buffer: &mut [u8], offset: usize) {
-        let key_stream = self.key.iter().cycle().skip(offset % self.key.len());
-        for (datum, &k) in buffer.iter_mut().zip(key_stream) {
-            *datum ^= k;
-        }
-    }
-}
-
-#[test]
-fn test_v2_init() -> Result<(), KugouError> {
-    let hdr_v2 = Header::from_buffer(include_bytes!("__fixtures__/kgm_v2_hdr.bin"))?;
-    DecipherV2::new(&hdr_v2)?;
-
-    Ok(())
-}

um_crypto/kgm/src/v3.rs

@@ -1,48 +0,0 @@
-use crate::header::Header;
-use crate::{Decipher, KugouError};
-
-pub struct DecipherV3 {
-    slot_key: [u8; 16],
-    file_key: [u8; 17],
-}
-
-impl DecipherV3 {
-    fn hash_key<T: AsRef<[u8]>>(data: T) -> [u8; 16] {
-        let digest = umc_utils::md5(data);
-        let mut result = [0u8; 16];
-        for (result, digest) in result.rchunks_exact_mut(2).zip(digest.chunks_exact(2)) {
-            result[0] = digest[0];
-            result[1] = digest[1];
-        }
-        result
-    }
-
-    pub fn new(header: &Header, slot_key: &[u8]) -> Result<Self, KugouError> {
-        let slot_key = Self::hash_key(slot_key);
-
-        let mut file_key = [0x6b; 17];
-        file_key[..16].copy_from_slice(&Self::hash_key(header.file_key));
-
-        Ok(Self { slot_key, file_key })
-    }
-}
-
-impl Decipher for DecipherV3 {
-    fn decrypt(&self, buffer: &mut [u8], offset: usize) {
-        let slot_key_stream = self.slot_key.iter().cycle().skip(offset);
-        let file_key_stream = self.file_key.iter().cycle().skip(offset);
-
-        let mut offset = offset as u32;
-        let key_stream = slot_key_stream.zip(file_key_stream);
-        for (datum, (&slot_key, &file_key)) in buffer.iter_mut().zip(key_stream) {
-            let mut temp = *datum;
-            temp ^= file_key;
-            temp ^= temp.wrapping_shl(4);
-            temp ^= slot_key;
-            temp ^= offset.to_ne_bytes().iter().fold(0, |acc, &x| acc ^ x);
-            *datum = temp;
-
-            offset = offset.wrapping_add(1);
-        }
-    }
-}

um_crypto/kuwo/src/lib.rs

@@ -105,7 +105,7 @@ impl Header {
         })
     }
 
-    pub fn get_decipher<T>(&self, ekey: Option<T>) -> Result<Cipher>
+    pub fn get_cipher<T>(&self, ekey: Option<T>) -> Result<Cipher>
     where
         T: AsRef<[u8]>,
     {

um_crypto/utils/Cargo.toml

@@ -5,5 +5,3 @@ edition = "2021"
 
 [dependencies]
 base64 = "0.22.1"
-itertools = "0.13.0"
-md-5 = "0.10.6"

um_crypto/utils/src/lib.rs

@@ -1,3 +1 @@
 pub mod base64;
-mod md5;
-pub use md5::md5;

um_crypto/utils/src/md5.rs

@@ -1,5 +0,0 @@
-use md5::{Digest, Md5};
-
-pub fn md5<T: AsRef<[u8]>>(buffer: T) -> [u8; 16] {
-    Md5::digest(buffer).into()
-}

um_wasm/src/exports/kuwo.rs

@@ -25,9 +25,9 @@ impl JsKuwoHeader {
     }
 
     /// Create an instance of cipher (decipher) for decryption
-    #[wasm_bindgen(js_name=makeDecipher)]
+    #[wasm_bindgen(js_name=makeCipher)]
-    pub fn make_decipher(&self, ekey: Option<String>) -> Result<JsCipher, JsError> {
+    pub fn make_cipher(&self, ekey: Option<String>) -> Result<JsCipher, JsError> {
-        let cipher = self.0.get_decipher(ekey).map_err(map_js_error)?;
+        let cipher = self.0.get_cipher(ekey).map_err(map_js_error)?;
         Ok(JsCipher(cipher))
     }
 }