keyfork-mnemonic-generate: initial commit

.gitignore

@@ -0,0 +1 @@
+target

Cargo.lock

@@ -0,0 +1,93 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[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 = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "cpufeatures"
+version = "0.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a17b76ff3a4162b0b27f354a0c87015ddad39d35f9c0c36607a3bdd175dde1f1"
+dependencies = [
+ "libc",
+]
+
+[[package]]
+name = "crypto-common"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1bfb12502f3fc46cca1bb51ac28df9d618d813cdc3d2f25b9fe775a34af26bb3"
+dependencies = [
+ "generic-array",
+ "typenum",
+]
+
+[[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 = "generic-array"
+version = "0.14.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85649ca51fd72272d7821adaf274ad91c288277713d9c18820d8499a7ff69e9a"
+dependencies = [
+ "typenum",
+ "version_check",
+]
+
+[[package]]
+name = "keyfork-mnemonic-generate"
+version = "0.1.0"
+dependencies = [
+ "sha2",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.147"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b4668fb0ea861c1df094127ac5f1da3409a82116a4ba74fca2e58ef927159bb3"
+
+[[package]]
+name = "sha2"
+version = "0.10.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "479fb9d862239e610720565ca91403019f2f00410f1864c5aa7479b950a76ed8"
+dependencies = [
+ "cfg-if",
+ "cpufeatures",
+ "digest",
+]
+
+[[package]]
+name = "typenum"
+version = "1.16.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "497961ef93d974e23eb6f433eb5fe1b7930b659f06d12dec6fc44a8f554c0bba"
+
+[[package]]
+name = "version_check"
+version = "0.9.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"

Cargo.toml

@@ -0,0 +1,5 @@
+[workspace]
+
+members = [
+    "keyfork-mnemonic-generate"
+]

README.md

@@ -4,6 +4,10 @@ An opinionated and modular toolchain for generating and managing a wide range
 of cryptographic keys offline and on smartcards from a shared bip39 mnemonic
 phrase.
 
+This toolchain uses entropy generated from an agent controlling a bip32 seed
+to generate keypairs, ensuring the keys are deterministic and contextually
+unique.
+
 Note: The following document is all proposed, and not yet implemented.
 
 ## Features

keyfork-mnemonic-generate/Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "keyfork-mnemonic-generate"
+version = "0.1.0"

keyfork-mnemonic-generate/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "keyfork-mnemonic-generate"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+sha2 = "0.10.7"

keyfork-mnemonic-generate/src/main.rs

@@ -0,0 +1,140 @@
+use std::{
+    env,
+    error::Error,
+    fs::{read_dir, read_to_string, File},
+    io::Read,
+};
+
+use sha2::{Digest, Sha256};
+
+/// Usage: keyfork-mnemonic-generate
+/// CHECKS:
+/// * If the system is online
+/// * If a kernel is running post-BLAKE2
+///
+/// TODO:
+/// * --features kitchen-sink: load username; system time's most random, precise bits; hostname;
+///   kernel version; other env specific shit into a CSPRNG
+
+static WARNING_LINKS: [&str; 1] =
+    ["https://lore.kernel.org/lkml/20211223141113.1240679-2-Jason@zx2c4.com/"];
+
+fn check_kernel_version() {
+    let kernel_version = read_to_string("/proc/version").expect("/proc/version");
+    let v = kernel_version
+        .split(' ')
+        .nth(2)
+        .expect("Unable to parse kernel version")
+        .split('.')
+        .take(2)
+        .map(str::parse)
+        .map(|x| x.expect("Unable to parse kernel version number"))
+        .collect::<Vec<u32>>();
+    let [major, minor, ..] = v.as_slice() else {
+        panic!("Unable to determine major and minor: {kernel_version}");
+    };
+    assert!(
+        [major, minor] > [&5, &4],
+        "kernel can't generate clean entropy: {}",
+        WARNING_LINKS[0]
+    );
+}
+
+fn check_online() {
+    let paths = read_dir("/sys/class/net").expect("Unable to read network interfaces");
+    for entry in paths {
+        let mut path = entry.expect("Unable to read directory entry").path();
+        if path
+            .as_os_str()
+            .to_str()
+            .expect("Unable to decode UTF-8 filepath")
+            .split('/')
+            .last()
+            .unwrap()
+            == "lo"
+        {
+            continue;
+        }
+        path.push("operstate");
+        let isup = read_to_string(&path).expect("Unable to read operstate of network interfaces");
+        assert_ne!(isup.trim(), "up", "No network interfaces should be up");
+    }
+}
+
+fn build_wordlist() -> Vec<String> {
+    let wordlist_file = include_str!("wordlist.txt");
+    wordlist_file
+        .lines()
+        .skip(1)
+        .map(|x| x.trim().to_string())
+        .collect()
+}
+
+fn main() -> Result<(), Box<dyn Error>> {
+    if !env::vars()
+        .any(|(name, _)| name == "SHOOT_SELF_IN_FOOT" || name == "INSECURE_HARDWARE_ALLOWED")
+    {
+        check_kernel_version();
+        check_online();
+    }
+
+    let wordlist = build_wordlist();
+    assert_eq!(
+        wordlist.len(),
+        2usize.pow(11),
+        "Wordlist did not include correct word count"
+    );
+
+    let bit_size: usize = env::args()
+        .nth(1)
+        .unwrap_or(String::from("256"))
+        .parse()
+        .expect("Expected integer bit size");
+    assert!(
+        bit_size == 128 || bit_size == 256,
+        "Only 12 or 24 word mnemonics are supported"
+    );
+
+    let mut random_handle = File::open("/dev/urandom")?;
+    let entropy = &mut [0u8; 256 / 8];
+    random_handle.read_exact(&mut entropy[..])?;
+
+    let mut hasher = sha2::Sha256::new();
+    hasher.update(&entropy);
+    let hash = hasher.finalize();
+    let checksum = &hash[..bit_size / 32 / 8];
+
+    let seed = [&entropy[..bit_size / 8], checksum].concat();
+    let seed_bits = seed
+        .iter()
+        .flat_map(|byte| {
+            [
+                byte & (1 << 0) != 0,
+                byte & (1 << 1) != 0,
+                byte & (1 << 2) != 0,
+                byte & (1 << 3) != 0,
+                byte & (1 << 4) != 0,
+                byte & (1 << 5) != 0,
+                byte & (1 << 6) != 0,
+                byte & (1 << 7) != 0,
+            ]
+        })
+        .collect::<Vec<_>>();
+    let words = seed_bits.chunks_exact(11).map(|chunk| {
+        let index = usize::from(chunk[0])
+            + (usize::from(chunk[1]) << 1)
+            + (usize::from(chunk[2]) << 2)
+            + (usize::from(chunk[3]) << 3)
+            + (usize::from(chunk[4]) << 4)
+            + (usize::from(chunk[5]) << 5)
+            + (usize::from(chunk[6]) << 6)
+            + (usize::from(chunk[7]) << 7)
+            + (usize::from(chunk[8]) << 8)
+            + (usize::from(chunk[9]) << 9)
+            + (usize::from(chunk[10]) << 10);
+        wordlist[index].clone()
+    }).collect::<Vec<_>>();
+    println!("{}", words.join(" "));
+
+    Ok(())
+}