diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ea8c4bf
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/target
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..5ffacf7
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "des-dfa"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/src/des.rs b/src/des.rs
new file mode 100644
index 0000000..fcdb4c5
--- /dev/null
+++ b/src/des.rs
@@ -0,0 +1,184 @@
+//! A Rust implementation of the Data Encryption Standard (DES)
+
+const E: [u8; 48] = [
+    32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17,
+    16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1,
+];
+
+const P: [u8; 32] = [
+    16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10,
+    2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25,
+];
+
+const IP: [u8; 64] = [
+    58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4,
+    62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8,
+    57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3,
+    61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7,
+];
+
+const IP_INV: [u8; 64] = [
+    40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23, 63, 31,
+    38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29,
+    36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27,
+    34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49, 17, 57, 25,
+];
+
+const PC1: [u8; 56] = [
+     57, 49, 41, 33, 25, 17, 9, 1,  58, 50, 42, 34, 26, 18,
+     10, 2,  59, 51, 43, 35, 27, 19, 11, 3,  60, 52, 44, 36,
+     63, 55, 47, 39, 31, 23, 15, 7,  62, 54, 46, 38, 30, 22,
+     14, 6,  61, 53, 45, 37, 29, 21, 13, 5,  28, 20, 12, 4,
+];
+
+const PC2: [u8; 48] = [
+    14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10,
+    23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2,
+    41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48,
+    44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32,
+];
+
+const SHIFTS: [u8; 16] = [
+    1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1,
+];
+
+// S-boxes
+const SBOX: [[[u8; 16]; 4]; 8] = [
+    [
+        [14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7],
+        [0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8],
+        [4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0],
+        [15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13],
+    ],
+    [
+        [15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10],
+        [3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5],
+        [0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15],
+        [13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9],
+    ],
+    [
+        [10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8],
+        [13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1],
+        [13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7],
+        [1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12],
+    ],
+    [
+        [7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15],
+        [13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9],
+        [10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4],
+        [3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14],
+    ],
+    [
+        [2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9],
+        [14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6],
+        [4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14],
+        [11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3],
+    ],
+    [
+        [12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11],
+        [10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8],
+        [9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6],
+        [4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13],
+    ],
+    [
+        [4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1],
+        [13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6],
+        [1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2],
+        [6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12],
+    ],
+    [
+        [13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7],
+        [1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2],
+        [7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8],
+        [2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11],
+    ],
+];
+
+/// Permute bits from `input` (of size `input_size`) according to `table`.
+fn permute(input: u64, table: &[u8], input_size: u8) -> u64 {
+    let mut out = 0;
+    let len = table.len() as u8;
+    for (i, &t) in table.iter().enumerate() {
+        let bit = (input >> (input_size - t)) & 1;
+        out |= bit << (len - 1 - i as u8);
+    }
+    out
+}
+
+/// Split a 64-bit chunk into two 32-bit halves.
+fn cut_in_halves(x: u64) -> (u32, u32) {
+    (((x >> 32) & 0xFFFFFFFF) as u32, (x & 0xFFFFFFFF) as u32)
+}
+
+/// Left rotate a 28-bit chunk.
+fn rotate28(x: u32) -> u32 {
+    ((x << 1) & 0x0FFFFFFF) | ((x >> 27) & 1)
+}
+
+/// DES Key schedule: Generate the 16 48-bit subkeys from the 64-bit key.
+fn key_schedule(key: u64) -> [u64; 16] {
+    let mut subkeys = [0u64; 16];
+    // PC1
+    let t = permute(key, &PC1, 64);
+    // split into C and D (28 bits each)
+    let mut c = ((t >> 28) & 0x0FFFFFFF) as u32;
+    let mut d = (t & 0x0FFFFFFF) as u32;
+    for (i, &shift) in SHIFTS.iter().enumerate() {
+        // rotate
+        for _ in 0..shift {
+            c = rotate28(c);
+            d = rotate28(d);
+        }
+        let cd = ((c as u64) << 28) | (d as u64);
+        subkeys[i] = permute(cd, &PC2, 56);
+    }
+    subkeys
+}
+
+/// DES F-function.
+fn f(r: u32, subkey: u64) -> u32 {
+    let expanded = permute(r as u64, &E, 32) ^ subkey;
+    let mut s_out = 0u32;
+    // S-boxes
+    for i in 0..8 {
+        let block = ((expanded >> (42 - 6 * i)) & 0x3F) as u8;
+        let row = ((block & 0x20) >> 4) | (block & 1);
+        let col = (block & 0x1E) >> 1;
+        let val = SBOX[i][row as usize][col as usize] as u32;
+        s_out |= val << (28 - 4 * i);
+    }
+    permute(s_out as u64, &P, 32) as u32
+}
+
+/// Encrypt a single 64-bit block with DES.
+pub fn des_encrypt(block: u64, key: u64) -> u64 {
+    let subkeys = key_schedule(key);
+    // initial permutation
+    let ip = permute(block, &IP, 64);
+    let (mut l, mut r) = cut_in_halves(ip);
+    for &sk in &subkeys {
+        let tmp = r;
+        r = l ^ f(r, sk);
+        l = tmp;
+    }
+    // preoutput swap
+    let pre = ((r as u64) << 32) | (l as u64);
+    permute(pre, &IP_INV, 64)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_des() {
+        let clear = 0x5F153DA392030441;
+        let key = 0xB50CBFCF216071B5;
+        let cipher = des_encrypt(clear, key);
+        assert_eq!(cipher, 0xCC5EC6D28C948058);
+
+        let clear = 0x24BE1121ABAF3C8D;
+        let key = 0x6B16D49C4CFFCE9F;
+        let cipher = des_encrypt(clear, key);
+        assert_eq!(cipher, 0x54007B958D88F7F3);
+    }
+}
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..b52e2ed
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,9 @@
+mod des;
+use crate::des::des_encrypt;
+
+fn main() {
+    let clear = 0x0123456789ABCDEF;
+    let key = 0x0123456789ABCDEF;
+    let cipher = des_encrypt(clear, key);
+    println!("0x{:016x}", cipher);
+}