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Fixed and improved docstrings, added module level documentation

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This commit is contained in:
Benjamin Richner 2020-06-23 22:20:16 +02:00
parent 2730ca7e76
commit 0b077c4baf
1 changed files with 16 additions and 12 deletions
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28
src/zipcrypto.rs
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@ -1,5 +1,11 @@
//! Implementation of the ZipCrypto algorithm
//!
//! The following paper was used to implement the ZipCrypto algorithm:
//! [https://courses.cs.ut.ee/MTAT.07.022/2015_fall/uploads/Main/dmitri-report-f15-16.pdf](https://courses.cs.ut.ee/MTAT.07.022/2015_fall/uploads/Main/dmitri-report-f15-16.pdf)
use std::num::Wrapping; use std::num::Wrapping;
/// A container to hold the current key state
struct ZipCryptoKeys { struct ZipCryptoKeys {
key_0: Wrapping<u32>, key_0: Wrapping<u32>,
key_1: Wrapping<u32>, key_1: Wrapping<u32>,
@ -7,9 +13,6 @@ struct ZipCryptoKeys {
} }
impl ZipCryptoKeys { impl ZipCryptoKeys {
// Used this paper to implement ZipCrypto algo
// https://courses.cs.ut.ee/MTAT.07.022/2015_fall/uploads/Main/dmitri-report-f15-16.pdf
fn new() -> ZipCryptoKeys { fn new() -> ZipCryptoKeys {
ZipCryptoKeys { ZipCryptoKeys {
key_0: Wrapping(0x12345678), key_0: Wrapping(0x12345678),
@ -48,26 +51,26 @@ impl ZipCryptoKeys {
} }
} }
/// A ZipCrypto reader with unverified password
pub struct ZipCryptoReader<R> { pub struct ZipCryptoReader<R> {
file: R, file: R,
keys: ZipCryptoKeys, keys: ZipCryptoKeys,
} }
impl<R: std::io::Read> ZipCryptoReader<R> { impl<R: std::io::Read> ZipCryptoReader<R> {
/// Note: The password is `&[u8]` and not `&str` because the
/// [zip specification](https://pkware.cachefly.net/webdocs/APPNOTE/APPNOTE-6.3.3.TXT)
/// does not specify password encoding (see function `update_keys` in the specification).
/// Therefore, if `&str` was used, the password would be UTF-8 and it
/// would be impossible to decrypt files that were encrypted with a
/// password byte sequence that is unrepresentable in UTF-8.
pub fn new(file: R, password: &[u8]) -> ZipCryptoReader<R> { pub fn new(file: R, password: &[u8]) -> ZipCryptoReader<R> {
// Note: The password is &[u8] and not &str because the documentation
// https://pkware.cachefly.net/webdocs/APPNOTE/APPNOTE-6.3.3.TXT
// does not specify password encoding (see function update_keys)
// Therefore, if &str was used, the password would be UTF-8 and it
// would be impossible to decrypt files that were encrypted with a
// password byte sequence that is unrepresentable in UTF-8.
let mut result = ZipCryptoReader { let mut result = ZipCryptoReader {
file: file, file: file,
keys: ZipCryptoKeys::new(), keys: ZipCryptoKeys::new(),
}; };
// Key the cipher by updating the keys with the password // Key the cipher by updating the keys with the password.
for byte in password.iter() { for byte in password.iter() {
result.keys.update(*byte); result.keys.update(*byte);
} }
@ -75,7 +78,7 @@ impl<R: std::io::Read> ZipCryptoReader<R> {
result result
} }
/// Read the ZipCrypto header bytes and validate the password /// Read the ZipCrypto header bytes and validate the password.
pub fn validate( pub fn validate(
mut self, mut self,
crc32_plaintext: u32, crc32_plaintext: u32,
@ -98,6 +101,7 @@ impl<R: std::io::Read> ZipCryptoReader<R> {
} }
} }
/// A ZipCrypto reader with verified password
pub struct ZipCryptoReaderValid<R> { pub struct ZipCryptoReaderValid<R> {
reader: ZipCryptoReader<R>, reader: ZipCryptoReader<R>,
} }