mirror of
https://github.com/mii443/RustySecrets.git
synced 2025-08-22 16:25:32 +00:00
Remove CRC-24 dependency. Closes #3
This commit is contained in:
Frederic Jacobs
@ -1,8 +0,0 @@
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2015-02-03:
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* I changed the CRC-24 checksum computation to include the coding parameter
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K and the share number N so that these numbers are also protected.
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If you have older shares generated with a previous version, you can still
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decode the secret by simply removing the checksum part of the shares.
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* The README now includes more information about the inner workings of
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secretshare and also a note on "perfect secrecy".
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10
Cargo.lock
generated
10
Cargo.lock
generated
@ -2,17 +2,11 @@
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name = "secretshare"
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version = "0.1.6"
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dependencies = [
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"crc24 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
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"getopts 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
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"rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
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"rustc-serialize 0.3.18 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[[package]]
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name = "crc24"
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version = "0.1.6"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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[[package]]
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name = "getopts"
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version = "0.2.14"
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@ -20,7 +14,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
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[[package]]
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name = "libc"
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version = "0.2.8"
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version = "0.2.9"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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[[package]]
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@ -28,7 +22,7 @@ name = "rand"
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version = "0.3.14"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
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"libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
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"libc 0.2.9 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[[package]]
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@ -9,5 +9,4 @@ readme = "README.md"
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[dependencies]
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getopts = "^0.2.14"
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rustc-serialize = "^0.3.18"
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crc24 = "^0.1.6"
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rand = "^0.3.14"
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23
README.md
23
README.md
@ -17,11 +17,11 @@ Passing a secret to secretshare for encoding:
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```
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$ echo My secret | ./secretshare -e2,5
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2-1-1YAYwmOHqZ69jA-v+mz
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2-2-YJZQDGm22Y77Gw-IhSh
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2-3-+G9ovW9SAnUynQ-Elwi
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2-4-F7rAjX3UOa53KA-b2vm
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2-5-j0P4PHsw4lW+rg-XyNl
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2-1-1YAYwmOHqZ69jA
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2-2-YJZQDGm22Y77Gw
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2-3-+G9ovW9SAnUynQ
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2-4-F7rAjX3UOa53KA
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2-5-j0P4PHsw4lW+rg
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```
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The parameters following the `-e` option tell `secretshare` to create 5 shares of which 2 will be necessary for decoding.
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@ -29,7 +29,7 @@ The parameters following the `-e` option tell `secretshare` to create 5 shares o
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Decoding a subset of shares (one share per line) can be done like this:
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```
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$ echo -e "2-2-YJZQDGm22Y77Gw-IhSh \n 2-4-F7rAjX3UOa53KA-b2vm" | ./secretshare -d
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$ echo -e "2-2-YJZQDGm22Y77Gw \n 2-4-F7rAjX3UOa53KA" | ./secretshare -d
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My secret
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```
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@ -62,9 +62,9 @@ The generated shares are lines of ASCII text.
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# Structure of the shares
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```
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2-1-LiTyeXwEP71IUA-Qj6n
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^ ^ ^^^^^^^^^^^^^^ ^^^^
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K N D C
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2-1-LiTyeXwEP71IUA
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^ ^ ^^^^^^^^^^^^^^
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K N D
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```
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A share is built out of three or four parts separated with a minus: K-N-D-C.
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@ -73,10 +73,7 @@ how many distinct
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shares of a specific secret are necessary to be able to recover the
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secret. The number N identifies the share (ranging from 1 to the number
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of shares that have been created). The D part is a Base64 encoding of
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a specific share's raw data. The optional part C is a Base64 encoding
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of a CRC-24 checksum of the concatenation of K and N as bytes followed
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by the share's raw data (before Base64 encoding). The same checksum
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algorithm is used in the OpenPGP format for “ASCII amoring”.
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a specific share's raw data.
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# A word on the secrecy
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49
src/main.rs
49
src/main.rs
@ -1,6 +1,5 @@
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extern crate rustc_serialize as serialize;
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extern crate getopts;
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extern crate crc24;
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extern crate rand;
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use std::convert;
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@ -154,22 +153,7 @@ fn parse_k_n(s: &str) -> io::Result<(u8, u8)> {
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Ok((k, n))
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}
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/// computes a CRC-24 hash over the concatenated coding parameters k, n
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/// and the raw share data
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fn crc24_as_bytes(k: u8, n: u8, octets: &[u8]) -> [u8; 3] {
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use std::hash::Hasher;
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let mut h = crc24::Crc24Hasher::new();
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h.write(&[k, n]);
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h.write(octets);
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let v = h.finish();
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[((v >> 16) & 0xFF) as u8,
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((v >> 8) & 0xFF) as u8,
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( v & 0xFF) as u8]
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}
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fn perform_encode(k: u8, n: u8, with_checksums: bool) -> io::Result<()> {
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fn perform_encode(k: u8, n: u8) -> io::Result<()> {
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let secret = {
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let limit: usize = 0x10000;
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let stdin = io::stdin();
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@ -192,12 +176,7 @@ fn perform_encode(k: u8, n: u8, with_checksums: bool) -> io::Result<()> {
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};
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for (index, share) in shares.iter().enumerate() {
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let salad = share.to_base64(config);
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if with_checksums {
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let crc_bytes = crc24_as_bytes(k, (index+1) as u8, &**share);
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println!("{}-{}-{}-{}", k, index+1, salad, crc_bytes.to_base64(config));
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} else {
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println!("{}-{}-{}", k, index+1, salad);
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}
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println!("{}-{}-{}", k, index+1, salad);
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}
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Ok(())
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}
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@ -218,13 +197,12 @@ fn read_shares() -> io::Result<(u8, Vec<(u8,Vec<u8>)>)> {
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return Err(other_io_err("Share parse error: Expected 3 or 4 \
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parts searated by a minus sign", None));
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}
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let (k, n, p3, opt_p4) = {
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let (k, n, p3) = {
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let mut iter = parts.into_iter();
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let k = try!(iter.next().unwrap().parse::<u8>().map_err(pie2io));
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let n = try!(iter.next().unwrap().parse::<u8>().map_err(pie2io));
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let p3 = iter.next().unwrap();
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let opt_p4 = iter.next();
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(k, n, p3, opt_p4)
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(k, n, p3)
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};
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if k < 1 || n < 1 {
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return Err(other_io_err("Share parse error: Illegal K,N parameters", None));
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@ -233,20 +211,6 @@ fn read_shares() -> io::Result<(u8, Vec<(u8,Vec<u8>)>)> {
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p3.from_base64().map_err(|_| other_io_err(
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"Share parse error: Base64 decoding of data block failed", None ))
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);
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if let Some(check) = opt_p4 {
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if check.len() != 4 {
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return Err(other_io_err("Share parse error: Checksum part is \
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expected to be four characters", None));
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}
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let crc_bytes = try!(
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check.from_base64().map_err(|_| other_io_err(
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"Share parse error: Base64 decoding of checksum failed", None))
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);
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let mychksum = crc24_as_bytes(k, n, &*data);
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if crc_bytes != mychksum {
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return Err(other_io_err("Share parse error: Checksum mismatch", None));
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}
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}
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if let Some((ck, cl)) = opt_k_l {
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if ck != k || cl != data.len() {
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return Err(other_io_err("Incompatible shares", None));
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@ -311,7 +275,7 @@ fn main() {
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return;
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}
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let action: Result<_,_> =
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let action: Result<_,_> =
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match (opt_matches.opt_present("e"), opt_matches.opt_present("d")) {
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(false, false) => Err("Nothing to do! Use -e or -d"),
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(true, true) => Err("Use either -e or -d and not both"),
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@ -335,7 +299,7 @@ fn main() {
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let result =
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match action {
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Ok(Action::Encode(k,n)) => perform_encode(k, n, true),
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Ok(Action::Encode(k,n)) => perform_encode(k, n),
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Ok(Action::Decode) => perform_decode(),
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Err(e) => Err(other_io_err(e, None))
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};
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@ -345,4 +309,3 @@ fn main() {
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// env::set_exit_status(1); // FIXME: unstable feature
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}
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}
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