#57 hpke hybrid encryption

Cargo.toml

@@ -14,4 +14,4 @@ crate-type = ["dylib"]
 
 [dependencies]
 libc = "0.2.146"
-cas-lib = "0.2.0"
+cas-lib = {path = "../cas-lib"}

src/hpke/mod.rs

@@ -0,0 +1,91 @@
+use std::ffi::c_uchar;
+
+use cas_lib::hybrid::{cas_hybrid::CASHybrid, hpke::CASHPKE};
+use types::{HpkeDecrypt, HpkeEncrypt, HpkeKeyPair};
+
+mod types;
+
+#[no_mangle]
+pub extern "C" fn hpke_generate_keypair() -> HpkeKeyPair {
+    let (mut private_key, mut public_key, mut info_str) = <CASHPKE as CASHybrid>::generate_key_pair();
+    let private_key_capacity = private_key.capacity();
+    private_key.reserve_exact(private_key_capacity);
+    let public_key_capacity = public_key.capacity();
+    public_key.reserve_exact(public_key_capacity);
+    let info_str_capacity = info_str.capacity();
+    info_str.reserve_exact(info_str_capacity);
+    let return_result = HpkeKeyPair {
+        private_key_ptr: private_key.as_mut_ptr(),
+        private_key_ptr_length: private_key.len(),
+        public_key_ptr: public_key.as_mut_ptr(),
+        public_key_ptr_length: public_key.len(),
+        info_str_ptr: info_str.as_mut_ptr(),
+        info_str_ptr_length: info_str.len()
+    };
+    std::mem::forget(private_key);
+    std::mem::forget(public_key);
+    std::mem::forget(info_str);
+    return_result
+}
+
+#[no_mangle]
+pub extern "C" fn hpke_encrypt(
+    plaintext: *const c_uchar,
+    plaintext_length: usize,
+    public_key: *const c_uchar,
+    public_keylength: usize,
+    info_str: *const c_uchar,
+    info_str_length: usize,
+) -> HpkeEncrypt {
+    let plaintext = unsafe { std::slice::from_raw_parts(plaintext, plaintext_length) }.to_vec();
+    let public_key = unsafe { std::slice::from_raw_parts(public_key, public_keylength) }.to_vec();
+    let info_str = unsafe { std::slice::from_raw_parts(info_str, info_str_length) }.to_vec();
+    let (mut encapped_key, mut ciphertext, mut tag) = <CASHPKE as CASHybrid>::encrypt(plaintext, public_key, info_str);
+    let encapped_key_capacity = encapped_key.capacity();
+    encapped_key.reserve_exact(encapped_key_capacity);
+    let ciphertext_capacity = ciphertext.capacity();
+    ciphertext.reserve_exact(ciphertext_capacity);
+    let tag_capacity = tag.capacity();
+    tag.reserve_exact(tag_capacity);
+    let return_result = HpkeEncrypt {
+        encapped_key_ptr: encapped_key.as_mut_ptr(),
+        encapped_key_ptr_length: encapped_key.len(),
+        ciphertext_ptr: ciphertext.as_mut_ptr(),
+        ciphertext_ptr_length: ciphertext.len(),
+        tag_ptr: tag.as_mut_ptr(),
+        tag_ptr_length: tag.len()
+    };
+    std::mem::forget(encapped_key);
+    std::mem::forget(ciphertext);
+    std::mem::forget(tag);
+    return_result
+}
+
+#[no_mangle]
+pub extern "C" fn hpke_decrypt(
+    ciphertext: *const c_uchar,
+    ciphertext_length: usize,
+    private_key: *const c_uchar,
+    private_keylength: usize,
+    encapped_key: *const c_uchar,
+    encapped_key_length: usize,
+    tag: *const c_uchar,
+    tag_length: usize,
+    info_str: *const c_uchar,
+    info_str_length: usize,
+) -> HpkeDecrypt {
+    let ciphertext = unsafe { std::slice::from_raw_parts(ciphertext, ciphertext_length) }.to_vec();
+    let private_key = unsafe { std::slice::from_raw_parts(private_key, private_keylength) }.to_vec();
+    let encapped_key = unsafe { std::slice::from_raw_parts(encapped_key, encapped_key_length) }.to_vec();
+    let tag = unsafe { std::slice::from_raw_parts(tag, tag_length)}.to_vec();
+    let info_str = unsafe { std::slice::from_raw_parts(info_str, info_str_length) }.to_vec();
+    let mut plaintext = <CASHPKE as CASHybrid>::decrypt(ciphertext, private_key, encapped_key, tag, info_str);
+    let plaintext_capacity = plaintext.capacity();
+    plaintext.reserve_exact(plaintext_capacity);
+    let return_result = HpkeDecrypt {
+        plaintext_ptr: plaintext.as_mut_ptr(),
+        plaintext_ptr_length: plaintext.len()
+    };
+    std::mem::forget(plaintext);
+    return_result
+}

src/hpke/types.rs

@@ -0,0 +1,27 @@
+use std::ffi::c_uchar;
+
+#[repr(C)]
+pub struct HpkeKeyPair {
+    pub private_key_ptr: *mut c_uchar,
+    pub private_key_ptr_length: usize,
+    pub public_key_ptr: *mut c_uchar,
+    pub public_key_ptr_length: usize,
+    pub info_str_ptr: *mut c_uchar,
+    pub info_str_ptr_length: usize
+}
+
+#[repr(C)]
+pub struct HpkeEncrypt {
+    pub encapped_key_ptr: *mut c_uchar,
+    pub encapped_key_ptr_length: usize,
+    pub ciphertext_ptr: *mut c_uchar,
+    pub ciphertext_ptr_length: usize,
+    pub tag_ptr: *mut c_uchar,
+    pub tag_ptr_length: usize
+}
+
+#[repr(C)]
+pub struct HpkeDecrypt {
+    pub plaintext_ptr: *mut c_uchar,
+    pub plaintext_ptr_length: usize
+}

src/lib.rs

@@ -9,6 +9,7 @@ mod sha;
 mod x25519;
 mod ascon_aead;
 mod zstd;
+mod hpke;
 
 pub mod password_hashers {
     pub mod argon2;