feat: finalise XEX runner and testing

src/tasks/tasks01/xex.rs

@@ -0,0 +1,27 @@
+use anyhow::{anyhow, Result};
+use base64::prelude::*;
+use serde_json::Value;
+
+use crate::utils::ciphers::{xex_decrypt, xex_encrypt};
+
+pub fn fde_xex(args: &Value) -> Result<Vec<u8>> {
+    let key_string: String = serde_json::from_value(args["key"].clone())?;
+    let key: Vec<u8> = BASE64_STANDARD.decode(key_string)?;
+
+    let tweak_string: String = serde_json::from_value(args["tweak"].clone())?;
+    let tweak: Vec<u8> = BASE64_STANDARD.decode(tweak_string)?;
+
+    let input_string: String = serde_json::from_value(args["input"].clone())?;
+    let input: Vec<u8> = BASE64_STANDARD.decode(input_string)?;
+
+    let mode_string: String = serde_json::from_value(args["mode"].clone())?;
+
+    match mode_string.as_str() {
+        "encrypt" => Ok(xex_encrypt(key, &tweak, &input)?),
+        "decrypt" => Ok(xex_decrypt(key, &tweak, &input)?),
+        _ => Err(anyhow!(
+            "Failure: No compatible mode found. Data was: {:?}",
+            args
+        )),
+    }
+}