added the crypto crate with tests and function

Cargo.lock

@@ -2,12 +2,31 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "aead"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1973cfbc1a2daf9cf550e74e1f088c28e7f7d8c1e1418fb6c9dc5184b7e84c99"
+dependencies = [
+ "crypto-common",
+ "inout",
+]
+
 [[package]]
 name = "bitflags"
 version = "2.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b4388bee8683e3d04af747c73422af53102d2bd24d9eadb6cbc100baef4b43f8"
 
+[[package]]
+name = "block-buffer"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2f6c7dbe95a6ed67ad9f18e57daf93a2f034c524b99fd2b76d18fdfeb6660aa"
+dependencies = [
+ "hybrid-array",
+]
+
 [[package]]
 name = "bytes"
 version = "1.12.1"
@@ -20,6 +39,41 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
+[[package]]
+name = "chacha20"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d524456ba66e72eb8b115ff89e01e497f8e6d11d78b70b1aa13c0fbd97540a81"
+dependencies = [
+ "cfg-if",
+ "cipher",
+ "cpufeatures",
+ "rand_core",
+]
+
+[[package]]
+name = "chacha20poly1305"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b89e1c441e926b9c82a8d023f6e1b7ae0adcfaa7d621814e4d60789bac751cb"
+dependencies = [
+ "aead",
+ "chacha20",
+ "cipher",
+ "poly1305",
+]
+
+[[package]]
+name = "cipher"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e8cf2a2c93cd704877c0858356ed03480ff301ee950b43f1cbe4573b088bfa6c"
+dependencies = [
+ "block-buffer",
+ "crypto-common",
+ "inout",
+]
+
 [[package]]
 name = "cli"
 version = "1.0.0"
@@ -27,6 +81,49 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "cmov"
+version = "0.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0c9ea0ac24bc397ab3c98583a3c9ba74fa56b09a4449bbe172b9b1ddb016027a"
+
+[[package]]
+name = "cpufeatures"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b2a41393f66f16b0823bb79094d54ac5fbd34ab292ddafb9a0456ac9f87d201"
+dependencies = [
+ "libc",
+]
+
+[[package]]
+name = "crypto"
+version = "0.1.0"
+dependencies = [
+ "chacha20poly1305",
+ "rand",
+]
+
+[[package]]
+name = "crypto-common"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ce6e4c961d6cd6c9a86db418387425e8bdeaf05b3c8bc1411e6dca4c252f1453"
+dependencies = [
+ "getrandom",
+ "hybrid-array",
+ "rand_core",
+]
+
+[[package]]
+name = "ctutils"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d5515a3834141de9eafb9717ad39eea8247b5674e6066c404e8c4b365d2a29e"
+dependencies = [
+ "cmov",
+]
+
 [[package]]
 name = "errno"
 version = "0.3.14"
@@ -37,6 +134,36 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "300e883d756b2e4ec94e02791f39b04b522276138852cfc41d9fb7e904106099"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "r-efi",
+ "rand_core",
+]
+
+[[package]]
+name = "hybrid-array"
+version = "0.4.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "818356c5132c1fede50f837ca96afbe78ff42413047f4abb886217845e1b6c8c"
+dependencies = [
+ "typenum",
+]
+
+[[package]]
+name = "inout"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4250ce6452e92010fdf7268ccc5d14faa80bb12fc741938534c58f16804e03c7"
+dependencies = [
+ "hybrid-array",
+]
+
 [[package]]
 name = "libc"
 version = "0.2.186"
@@ -92,6 +219,16 @@ version = "0.2.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a89322df9ebe1c1578d689c92318e070967d1042b512afbe49518723f4e6d5cd"
 
+[[package]]
+name = "poly1305"
+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6e2d0073b297041425c7c3df6eb4792d598a15323fe63346852b092eca02904c"
+dependencies = [
+ "cpufeatures",
+ "universal-hash",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.106"
@@ -110,6 +247,29 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "r-efi"
+version = "6.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8dcc9c7d52a811697d2151c701e0d08956f92b0e24136cf4cf27b57a6a0d9bf"
+
+[[package]]
+name = "rand"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c7f5fa3a058cd35567ef9bfa5e75732bee0f9e4c55fa90477bef2dfcdbc4be80"
+dependencies = [
+ "chacha20",
+ "getrandom",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "63b8176103e19a2643978565ca18b50549f6101881c443590420e4dc998a3c69"
+
 [[package]]
 name = "redox_syscall"
 version = "0.5.18"
@@ -190,12 +350,28 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "typenum"
+version = "1.20.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6f5e870be6c3b371b77fe0ee0bafb859fa4964b4404c27de1d380043c4dda20"
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e6e4313cd5fcd3dad5cafa179702e2b244f760991f45397d14d4ebf38247da75"
 
+[[package]]
+name = "universal-hash"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f4987bdc12753382e0bec4a65c50738ffaabc998b9cdd1f952fb5f39b0048a96"
+dependencies = [
+ "crypto-common",
+ "ctutils",
+]
+
 [[package]]
 name = "wasi"
 version = "0.11.1+wasi-snapshot-preview1"

crates/crypto/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "crypto"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+chacha20poly1305 = { version = "0.11", features = ["getrandom"] }
+rand = "0.10"

crates/crypto/src/lib.rs

@@ -0,0 +1,56 @@
+use chacha20poly1305::{
+    ChaCha20Poly1305, Key, Nonce,
+    aead::{Aead, Generate, KeyInit},
+};
+
+type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
+
+mod helper {
+    use super::{Generate, Key, Nonce};
+    pub fn gen_nonce() -> Nonce {
+        Nonce::generate()
+    }
+
+    pub fn gen_key() -> Key {
+        Key::generate()
+    }
+}
+
+pub fn encrypt(key: &Key, plaintext: Vec<u8>) -> Result<(Nonce, Vec<u8>)> {
+    let cipher = ChaCha20Poly1305::new(key);
+
+    let nonce = helper::gen_nonce();
+
+    let ciphertext = cipher.encrypt(&nonce, plaintext.as_ref())?;
+
+    Ok((nonce, ciphertext))
+}
+
+pub fn decrypt(key: &Key, ciphertext: Vec<u8>, nonce: &Nonce) -> Result<Vec<u8>> {
+    let cipher = ChaCha20Poly1305::new(key);
+
+    let plaintext = cipher.decrypt(nonce, ciphertext.as_ref())?;
+
+    Ok(plaintext)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::result::Result;
+
+    #[test]
+    fn encryption_decryption() -> Result<(), Box<dyn std::error::Error>> {
+        let key = helper::gen_key();
+        let plaintext = "I alone am the honored one.\n - Saturo Gojo.";
+
+        let (nonce, ciphertext) = encrypt(&key, plaintext.into())?;
+
+        let transformed = decrypt(&key, ciphertext, &nonce)?;
+
+        assert_eq!(plaintext.as_bytes(), transformed);
+
+        Ok(())
+    }
+}
+