pv: Implement HostKey::V2 and Keyslot::V2

Introduce HybridPublicKey combining ECDH and ML-KEM public keys. Use it
for HostKey::V2 and add Keyslot::V2 for hybrid keyslots.

Add tests for the new functionality.

Assisted-by: IBM Bob:1.0.5
Signed-off-by: Timo Keller <tkeller@linux.ibm.com>
Reviewed-by: Marc Hartmayer <marc@linux.ibm.com>
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>

rust/pv/src/req/hostkey.rs

@@ -4,7 +4,56 @@
 
 //! Host key types for UV requests
 
-use openssl::pkey::{PKey, PKeyRef, Public};
+use openssl::nid::Nid;
+use openssl::pkey::{KeyType, PKey, PKeyRef, Public};
+
+use crate::crypto::{validate_ec_key, validate_key_type};
+pub use crate::error::Result;
+
+/// Hybrid public key (ECDH and ML-KEM)
+#[derive(Clone, Debug)]
+pub struct HybridPKey {
+    /// ECDH public key
+    pub(super) ec_key: PKey<Public>,
+
+    /// ML-KEM public key
+    pub(super) mlkem_key: PKey<Public>,
+}
+
+impl HybridPKey {
+    /// Creates a new hybrid public key with validation.
+    ///
+    /// # Parameters
+    /// - `ec_key`: ECDH public key (must be SECP521R1)
+    /// - `mlkem_key`: ML-KEM public key (must be ML-KEM-1024)
+    ///
+    /// # Errors
+    /// Returns an error if:
+    /// - EC key is not SECP521R1 curve
+    /// - ML-KEM key is not ML-KEM-1024
+    pub fn new(ec_key: PKey<Public>, mlkem_key: PKey<Public>) -> Result<Self> {
+        validate_ec_key(&ec_key, "ECDH key", Nid::SECP521R1)?;
+        validate_key_type(&mlkem_key, "ML-KEM key", KeyType::ML_KEM_1024)?;
+
+        Ok(Self { ec_key, mlkem_key })
+    }
+
+    /// Returns a reference to the EC key
+    pub fn ec_key(&self) -> &PKeyRef<Public> {
+        &self.ec_key
+    }
+
+    /// Returns a reference to the ML-KEM key
+    pub fn mlkem_key(&self) -> &PKeyRef<Public> {
+        &self.mlkem_key
+    }
+}
+
+impl AsRef<HybridPKey> for HybridPKey {
+    fn as_ref(&self) -> &HybridPKey {
+        self
+    }
+}
 
 /// Versioned host keys container
 #[non_exhaustive]
@@ -12,6 +61,9 @@ use openssl::pkey::{PKey, PKeyRef, Public};
 pub enum HostKey {
     /// ECDH public key
     V1(PKey<Public>),
+
+    /// Hybrid public key (ECDH and ML-KEM)
+    V2(HybridPKey),
 }
 
 impl HostKey {
@@ -19,8 +71,23 @@ impl HostKey {
     pub fn ec_key(&self) -> Option<&PKeyRef<Public>> {
         Some(match self {
             HostKey::V1(ec_key) => ec_key,
+            HostKey::V2(hybrid) => hybrid.ec_key(),
         })
     }
+
+    /// Return the ML-KEM public key
+    pub fn mlkem_key(&self) -> Option<&PKeyRef<Public>> {
+        match self {
+            HostKey::V1(_) => None,
+            HostKey::V2(hybrid) => Some(hybrid.mlkem_key()),
+        }
+    }
+
+    /// Test if the hostkey is hybrid
+    #[must_use]
+    pub fn is_hybrid(&self) -> bool {
+        matches!(self, HostKey::V2(_))
+    }
 }
 
 impl AsRef<HostKey> for HostKey {
@@ -28,3 +95,248 @@ impl AsRef<HostKey> for HostKey {
         self
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use openssl::ec::{EcGroup, EcKey};
+    use openssl::pkey::Private;
+
+    use super::*;
+    use crate::openssl_extensions::generate_ml_kem;
+    use crate::test_utils::get_test_key_and_cert_hybrid;
+    use crate::Error;
+
+    fn to_public_key(key: &PKey<Private>) -> Result<PKey<Public>> {
+        let der = key.public_key_to_der()?;
+        Ok(PKey::public_key_from_der(&der)?)
+    }
+
+    #[test]
+    fn test_hostkey_v1_variant() {
+        let (_, ec_key) = crate::test_utils::get_test_key_and_cert();
+        let hostkey = HostKey::V1(ec_key.public_key().unwrap());
+
+        assert!(!hostkey.is_hybrid(), "V1 HostKey should not be hybrid");
+        assert!(matches!(hostkey, HostKey::V1(_)));
+    }
+
+    #[test]
+    fn test_hostkey_v2_variant() {
+        let (_, ec_key, mlkem_key) = get_test_key_and_cert_hybrid();
+        let hybrid = HybridPKey::new(
+            ec_key.public_key().unwrap(),
+            mlkem_key.public_key().unwrap(),
+        )
+        .unwrap();
+        let hostkey = HostKey::V2(hybrid);
+
+        assert!(hostkey.is_hybrid(), "V2 HostKey should be hybrid");
+        assert!(matches!(hostkey, HostKey::V2(_)));
+    }
+
+    #[test]
+    fn test_hostkey_ec_key_access() {
+        let (_, ec_key, mlkem_key) = get_test_key_and_cert_hybrid();
+        let hybrid = HybridPKey::new(
+            ec_key.public_key().unwrap(),
+            mlkem_key.public_key().unwrap(),
+        )
+        .unwrap();
+
+        let v1_key = HostKey::V1(ec_key.public_key().unwrap());
+        let v2_key = HostKey::V2(hybrid);
+
+        assert!(v1_key.ec_key().unwrap().public_key_to_der().is_ok());
+        assert!(v2_key.ec_key().unwrap().public_key_to_der().is_ok());
+    }
+
+    #[test]
+    fn test_hostkey_v2_mlkem_key_access() {
+        let (_, ec_key, mlkem_key) = get_test_key_and_cert_hybrid();
+        let hybrid = HybridPKey::new(
+            ec_key.public_key().unwrap(),
+            mlkem_key.public_key().unwrap(),
+        )
+        .unwrap();
+        let hostkey = HostKey::V2(hybrid);
+
+        assert!(hostkey.mlkem_key().unwrap().public_key_to_der().is_ok());
+    }
+
+    #[test]
+    fn test_hostkey_v1_has_no_mlkem_key() {
+        let (_, ec_key) = crate::test_utils::get_test_key_and_cert();
+        let hostkey = HostKey::V1(ec_key.public_key().unwrap());
+
+        assert!(hostkey.mlkem_key().is_none());
+    }
+
+    #[test]
+    fn test_hybrid_public_key_structure() {
+        let (_, ec_key, mlkem_key) = get_test_key_and_cert_hybrid();
+        let hybrid = HybridPKey::new(
+            ec_key.public_key().unwrap(),
+            mlkem_key.public_key().unwrap(),
+        )
+        .unwrap();
+
+        // Verify both components are present and valid
+        assert!(!hybrid.ec_key().public_key_to_der().unwrap().is_empty());
+        assert!(!hybrid.mlkem_key().public_key_to_der().unwrap().is_empty());
+    }
+
+    #[test]
+    fn test_hybrid_pkey_invalid_ec_curve() {
+        // Generate a P-256 key instead of P-521
+        let group = EcGroup::from_curve_name(Nid::X9_62_PRIME256V1).unwrap();
+        let wrong_ec_key = PKey::from_ec_key(EcKey::generate(&group).unwrap()).unwrap();
+
+        let (_, _, mlkem_key) = get_test_key_and_cert_hybrid();
+
+        let result = HybridPKey::new(
+            to_public_key(&wrong_ec_key).unwrap(),
+            mlkem_key.public_key().unwrap(),
+        );
+        assert!(result.is_err(), "Should reject EC key with wrong curve");
+
+        if let Err(Error::RetrInvKey {
+            what,
+            kind,
+            value,
+            exp,
+        }) = result
+        {
+            assert_eq!(what, "curve");
+            assert_eq!(kind, "ECDH key");
+            assert_eq!(value, "prime256v1");
+            assert_eq!(exp, "secp521r1");
+        } else {
+            panic!("Expected RetrInvKey error for wrong curve");
+        }
+    }
+
+    #[test]
+    fn test_hybrid_pkey_invalid_mlkem_type() {
+        let (_, ec_key, _) = get_test_key_and_cert_hybrid();
+
+        // Generate ML-KEM-512 instead of ML-KEM-1024
+        let wrong_mlkem_key = generate_ml_kem(KeyType::ML_KEM_512).unwrap();
+
+        let result = HybridPKey::new(
+            ec_key.public_key().unwrap(),
+            to_public_key(&wrong_mlkem_key).unwrap(),
+        );
+        assert!(result.is_err(), "Should reject ML-KEM key with wrong type");
+
+        if let Err(Error::RetrInvKey {
+            what,
+            kind,
+            value,
+            exp,
+        }) = result
+        {
+            assert_eq!(what, "key type");
+            assert_eq!(kind, "ML-KEM key");
+            assert_eq!(value, "ML-KEM-512");
+            assert_eq!(exp, "ML-KEM-1024");
+        } else {
+            panic!("Expected RetrInvKey error for wrong ML-KEM type");
+        }
+    }
+
+    #[test]
+    fn test_hybrid_pkey_clone() {
+        let (_, ec_key, mlkem_key) = get_test_key_and_cert_hybrid();
+        let hybrid = HybridPKey::new(
+            ec_key.public_key().unwrap(),
+            mlkem_key.public_key().unwrap(),
+        )
+        .unwrap();
+
+        let cloned = hybrid.clone();
+
+        // Verify both original and clone have valid keys
+        assert!(!hybrid.ec_key().public_key_to_der().unwrap().is_empty());
+        assert!(!hybrid.mlkem_key().public_key_to_der().unwrap().is_empty());
+        assert!(!cloned.ec_key().public_key_to_der().unwrap().is_empty());
+        assert!(!cloned.mlkem_key().public_key_to_der().unwrap().is_empty());
+
+        // Verify the keys are equivalent
+        assert_eq!(
+            hybrid.ec_key().public_key_to_der().unwrap(),
+            cloned.ec_key().public_key_to_der().unwrap()
+        );
+        assert_eq!(
+            hybrid.mlkem_key().public_key_to_der().unwrap(),
+            cloned.mlkem_key().public_key_to_der().unwrap()
+        );
+    }
+
+    #[test]
+    fn test_hostkey_clone() {
+        let (_, ec_key, mlkem_key) = get_test_key_and_cert_hybrid();
+        let hybrid = HybridPKey::new(
+            ec_key.public_key().unwrap(),
+            mlkem_key.public_key().unwrap(),
+        )
+        .unwrap();
+
+        // Test cloning V1
+        let v1_key = HostKey::V1(ec_key.public_key().unwrap());
+        let v1_cloned = v1_key.clone();
+        assert!(!v1_cloned.is_hybrid());
+        assert_eq!(
+            v1_key.ec_key().unwrap().public_key_to_der().unwrap(),
+            v1_cloned.ec_key().unwrap().public_key_to_der().unwrap()
+        );
+
+        // Test cloning V2
+        let v2_key = HostKey::V2(hybrid);
+        let v2_cloned = v2_key.clone();
+        assert!(v2_cloned.is_hybrid());
+        assert_eq!(
+            v2_key.ec_key().unwrap().public_key_to_der().unwrap(),
+            v2_cloned.ec_key().unwrap().public_key_to_der().unwrap()
+        );
+        assert_eq!(
+            v2_key.mlkem_key().unwrap().public_key_to_der().unwrap(),
+            v2_cloned.mlkem_key().unwrap().public_key_to_der().unwrap()
+        );
+    }
+
+    #[test]
+    fn test_hybrid_pkey_as_ref() {
+        let (_, ec_key, mlkem_key) = get_test_key_and_cert_hybrid();
+        let hybrid = HybridPKey::new(
+            ec_key.public_key().unwrap(),
+            mlkem_key.public_key().unwrap(),
+        )
+        .unwrap();
+
+        let hybrid_ref: &HybridPKey = hybrid.as_ref();
+        assert!(!hybrid_ref.ec_key().public_key_to_der().unwrap().is_empty());
+        assert!(!hybrid_ref
+            .mlkem_key()
+            .public_key_to_der()
+            .unwrap()
+            .is_empty());
+    }
+
+    #[test]
+    fn test_hostkey_as_ref() {
+        let (_, ec_key, mlkem_key) = get_test_key_and_cert_hybrid();
+        let hybrid = HybridPKey::new(
+            ec_key.public_key().unwrap(),
+            mlkem_key.public_key().unwrap(),
+        )
+        .unwrap();
+
+        let v1_key = HostKey::V1(ec_key.public_key().unwrap());
+        let v1_ref: &HostKey = v1_key.as_ref();
+        assert!(!v1_ref.is_hybrid());
+
+        let v2_key = HostKey::V2(hybrid);
+        let v2_ref: &HostKey = v2_key.as_ref();
+        assert!(v2_ref.is_hybrid());
+    }
+}

rust/pv/src/req/keyslot.rs

@@ -7,11 +7,8 @@
 use openssl::hash::MessageDigest;
 use openssl::pkey::{PKey, PKeyRef, Private, Public};
 
-use super::ec_coord::EcPubKeyCoord;
-use super::encrypt::Encrypt;
-#[expect(unused)]
 use crate::crypto::{derive_aes256_gcm_key, derive_aes256_gcm_key_hybrid, encrypt_aead, hash};
-use crate::request::HostKey;
+use crate::req::{EcPubKeyCoord, Encrypt, HostKey, HybridPKey};
 use crate::Result;
 
 /// IBM Z Host key-slot
@@ -72,12 +69,100 @@ impl Encrypt for KeyslotV1 {
     }
 }
 
+/// IBM Z hybrid (V2) Host key-slot
+///
+/// Layout in binary format:
+/// ```none
+/// _______________________________________________________________
+/// |   Public Host Key Hash (64)                                 |
+/// |   Wrapped(=Encrypted) Request Protection Key(32)            |
+/// |   Key Slot Tag (16)                                         |
+/// |   ML-KEM Ciphertext (1568)                                  |
+/// |_____________________________________________________________|
+/// ```
+#[derive(Debug, Clone)]
+pub struct KeyslotV2 {
+    ec_hostkey: PKey<Public>,
+    mlkem_hostkey: PKey<Public>,
+}
+
+impl KeyslotV2 {
+    /// Size of a hybrid host-key hash
+    pub const PHKH_SIZE: u32 = 0x40;
+    /// Size of a complete V2 keyslot in bytes
+    pub const SIZE: usize = 1680;
+
+    /// Creates a new HybridKeyslot from the provided hybrid public key
+    pub fn new(hostkey: HybridPKey) -> Self {
+        let HybridPKey { ec_key, mlkem_key } = hostkey;
+        Self {
+            ec_hostkey: ec_key,
+            mlkem_hostkey: mlkem_key,
+        }
+    }
+
+    /// Encrypts `secret` using `self` and `priv_key` the encryption.
+    ///
+    /// # Returns
+    /// the encrypted data.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an error if OpenSSL could not encrypt the secret.
+    pub fn encrypt(&self, secret: &[u8], priv_key: &PKeyRef<Private>) -> Result<Vec<u8>> {
+        let mut res = Vec::with_capacity(1680);
+        self.encrypt_to(secret, priv_key, &mut res)?;
+        Ok(res)
+    }
+
+    /// Encrypts the given request protection key `prot_key`.
+    ///
+    /// The AES256 encryption key is derived from `self` as public key, and `priv_key` as private
+    /// key.
+    ///
+    /// # Returns
+    /// The encrypted HybridKeyslot.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an error if OpenSSL could not encrypt the secret.
+    fn encrypt_to(
+        &self,
+        prot_key: &[u8],
+        priv_key: &PKeyRef<Private>,
+        to: &mut Vec<u8>,
+    ) -> Result<()> {
+        let mut phk_buf = Vec::<u8>::with_capacity(160 + 1568);
+        let ec_phk: EcPubKeyCoord = self.ec_hostkey.as_ref().try_into()?;
+        phk_buf.extend_from_slice(ec_phk.as_ref());
+        phk_buf.extend_from_slice(&self.mlkem_hostkey.raw_public_key()?);
+        assert_eq!(phk_buf.len(), 160 + 1568);
+
+        let (derived_key, ciphertext) =
+            derive_aes256_gcm_key_hybrid(priv_key, &self.ec_hostkey, &self.mlkem_hostkey)?;
+        let mut wrpk_and_kst =
+            encrypt_aead(&derived_key.into(), &[0; 12], &[], prot_key)?.into_buf();
+        assert_eq!(wrpk_and_kst.len(), 48);
+
+        to.reserve(1680);
+        let hash = hash(MessageDigest::sha512(), &phk_buf)?;
+        assert_eq!(hash.len(), 64);
+        to.extend_from_slice(&hash);
+        to.append(&mut wrpk_and_kst);
+        assert_eq!(ciphertext.len(), 1568);
+        to.extend_from_slice(&ciphertext);
+        Ok(())
+    }
+}
+
 /// Versioned keyslot container
 #[non_exhaustive]
 #[derive(Debug, Clone)]
 pub enum Keyslot {
     /// V1 key-slots with ECDH keys
     V1(KeyslotV1),
+    /// V2 key-slots with hybrid ECDH/ML-KEM keys
+    V2(KeyslotV2),
 }
 
 impl Keyslot {
@@ -85,6 +170,7 @@ impl Keyslot {
     pub fn new(hostkey: HostKey) -> Self {
         match hostkey {
             HostKey::V1(key) => Keyslot::V1(KeyslotV1::new(key)),
+            HostKey::V2(key) => Keyslot::V2(KeyslotV2::new(key)),
         }
     }
 
@@ -92,6 +178,7 @@ impl Keyslot {
     pub fn phkh_size(&self) -> u32 {
         match self {
             Keyslot::V1(_) => KeyslotV1::PHKH_SIZE,
+            Keyslot::V2(_) => KeyslotV2::PHKH_SIZE,
         }
     }
 
@@ -99,13 +186,16 @@ impl Keyslot {
     pub fn size(&self) -> usize {
         match self {
             Keyslot::V1(_) => KeyslotV1::SIZE,
+            Keyslot::V2(_) => KeyslotV2::SIZE,
         }
     }
 
     /// Return whether the key-slot uses hybrid keys
+    #[must_use]
     pub fn is_hybrid(&self) -> bool {
         match self {
             Keyslot::V1(_) => false,
+            Keyslot::V2(_) => true,
         }
     }
 }
@@ -119,6 +209,7 @@ impl Encrypt for Keyslot {
     ) -> Result<()> {
         match self {
             Keyslot::V1(ks) => ks.encrypt_to(secret, priv_key, to),
+            Keyslot::V2(ks) => ks.encrypt_to(secret, priv_key, to),
         }
     }
 }
@@ -129,11 +220,17 @@ impl From<PKey<Public>> for Keyslot {
     }
 }
 
+impl From<HybridPKey> for Keyslot {
+    fn from(key: HybridPKey) -> Self {
+        Keyslot::V2(KeyslotV2::new(key))
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::get_test_asset;
-    use crate::test_utils::*;
+    use crate::test_utils::{DeterministicTestRandGuard, *};
 
     #[test]
     fn keyslot() {
@@ -148,4 +245,214 @@ mod tests {
         let encr_ks = keyslot.encrypt(&[0x16u8; 32], &cust_key).unwrap();
         assert_ne!(exp_keyslot, encr_ks);
     }
+
+    #[test]
+    fn keyslot_v2() {
+        // Install deterministic RNG for reproducible encryption
+        let _guard = DeterministicTestRandGuard::install(&[0x42; 64], &[0x17; 16]).unwrap();
+
+        let (cust_key, host_key1, host_key2) = get_test_keys_hybrid();
+        let host_key = HostKey::V2(HybridPKey::new(host_key1, host_key2).unwrap());
+        let exp_keyslot = vec![
+            255, 94, 191, 53, 220, 196, 47, 37, 93, 227, 234, 101, 1, 174, 171, 68, 42, 136, 92,
+            238, 72, 6, 17, 77, 231, 225, 174, 22, 222, 188, 212, 15, 248, 145, 72, 126, 139, 17,
+            233, 225, 156, 46, 233, 151, 54, 2, 175, 88, 215, 254, 243, 222, 37, 81, 50, 110, 18,
+            76, 252, 12, 210, 146, 66, 23, 123, 246, 141, 14, 70, 157, 73, 124, 205, 112, 192, 82,
+            160, 243, 2, 154, 134, 145, 176, 147, 30, 217, 221, 93, 170, 239, 165, 37, 30, 192, 47,
+            94, 129, 165, 12, 137, 239, 12, 180, 199, 240, 160, 180, 205, 117, 84, 16, 148, 51, 48,
+            243, 216, 50, 132, 187, 115, 137, 3, 109, 145, 172, 159, 224, 25, 63, 96, 241, 105, 89,
+            35, 42, 180, 248, 35, 166, 81, 116, 175, 179, 252, 81, 188, 189, 42, 17, 60, 231, 132,
+            32, 111, 90, 138, 201, 16, 3, 97, 246, 130, 173, 85, 218, 187, 232, 92, 52, 120, 56,
+            142, 137, 101, 31, 21, 194, 186, 198, 38, 240, 58, 150, 93, 86, 18, 186, 5, 12, 41, 37,
+            94, 162, 119, 16, 237, 82, 252, 178, 159, 57, 58, 162, 20, 173, 140, 10, 172, 203, 241,
+            94, 110, 117, 32, 36, 217, 7, 168, 50, 105, 43, 33, 174, 140, 55, 88, 26, 233, 81, 253,
+            98, 121, 190, 70, 146, 84, 186, 6, 51, 181, 2, 59, 216, 45, 78, 4, 82, 90, 21, 180, 99,
+            239, 195, 254, 33, 171, 124, 97, 36, 110, 119, 142, 98, 125, 70, 236, 51, 192, 32, 8,
+            214, 224, 101, 169, 45, 173, 137, 194, 78, 114, 224, 76, 174, 188, 133, 227, 167, 169,
+            47, 241, 190, 15, 145, 217, 87, 254, 15, 150, 52, 138, 192, 230, 52, 129, 36, 8, 40,
+            37, 126, 103, 85, 86, 25, 78, 53, 243, 107, 193, 18, 102, 3, 83, 212, 5, 252, 224, 241,
+            7, 205, 220, 168, 183, 15, 37, 52, 190, 12, 9, 152, 124, 210, 65, 152, 210, 199, 81,
+            95, 240, 141, 196, 236, 8, 249, 221, 116, 130, 42, 52, 208, 218, 180, 27, 249, 59, 245,
+            21, 165, 142, 234, 140, 75, 89, 136, 250, 155, 157, 12, 154, 152, 188, 178, 227, 237,
+            124, 111, 176, 131, 227, 238, 164, 22, 88, 80, 217, 42, 217, 80, 148, 118, 12, 136, 95,
+            53, 69, 209, 131, 74, 91, 193, 253, 229, 146, 11, 58, 125, 19, 8, 229, 60, 177, 244,
+            74, 41, 92, 91, 62, 64, 221, 20, 213, 227, 4, 40, 22, 177, 155, 236, 147, 165, 27, 4,
+            99, 4, 151, 155, 82, 72, 151, 22, 102, 183, 192, 242, 18, 104, 146, 205, 107, 21, 254,
+            88, 23, 69, 246, 57, 217, 249, 124, 246, 54, 163, 244, 38, 74, 215, 144, 50, 45, 142,
+            36, 216, 88, 39, 70, 67, 88, 130, 1, 8, 205, 240, 159, 210, 205, 233, 237, 60, 81, 176,
+            112, 172, 187, 121, 239, 198, 43, 17, 49, 55, 170, 228, 243, 255, 76, 72, 121, 125,
+            157, 250, 93, 251, 55, 25, 4, 129, 67, 195, 30, 37, 6, 76, 10, 240, 178, 255, 151, 138,
+            36, 255, 32, 237, 133, 162, 130, 91, 9, 238, 67, 134, 4, 86, 225, 179, 166, 219, 4,
+            144, 7, 125, 248, 75, 132, 54, 56, 51, 237, 206, 252, 96, 9, 208, 140, 127, 143, 180,
+            32, 179, 254, 18, 233, 187, 122, 159, 172, 77, 204, 9, 179, 242, 153, 18, 138, 82, 13,
+            210, 140, 207, 9, 217, 216, 241, 106, 205, 109, 195, 223, 82, 172, 181, 48, 91, 124,
+            235, 85, 17, 18, 166, 216, 86, 120, 185, 54, 147, 156, 84, 106, 30, 235, 234, 114, 27,
+            23, 121, 210, 251, 136, 117, 53, 177, 28, 153, 144, 17, 70, 190, 206, 27, 135, 42, 227,
+            39, 243, 86, 170, 11, 63, 191, 102, 89, 92, 137, 103, 59, 142, 236, 203, 156, 231, 255,
+            30, 5, 86, 53, 59, 76, 181, 218, 184, 244, 21, 50, 100, 72, 81, 98, 193, 34, 58, 67,
+            150, 15, 17, 162, 216, 119, 213, 203, 50, 27, 158, 61, 105, 134, 151, 200, 68, 103, 74,
+            207, 12, 5, 163, 30, 198, 28, 41, 41, 97, 93, 251, 213, 133, 41, 225, 178, 67, 160, 85,
+            132, 146, 1, 201, 99, 49, 185, 27, 150, 213, 165, 134, 45, 248, 204, 67, 145, 49, 81,
+            35, 246, 25, 215, 209, 159, 106, 212, 14, 149, 193, 163, 90, 24, 83, 230, 178, 216,
+            194, 130, 118, 169, 81, 49, 49, 145, 96, 206, 216, 15, 134, 43, 130, 25, 110, 84, 39,
+            175, 223, 183, 209, 123, 5, 166, 244, 19, 89, 2, 47, 226, 3, 93, 156, 163, 67, 156,
+            237, 17, 59, 69, 99, 94, 32, 180, 64, 64, 115, 75, 44, 241, 150, 43, 169, 17, 36, 125,
+            216, 132, 92, 3, 244, 16, 83, 179, 192, 65, 133, 208, 19, 156, 17, 60, 54, 29, 253,
+            237, 18, 158, 145, 142, 232, 147, 2, 91, 21, 145, 125, 204, 243, 161, 245, 110, 140,
+            219, 206, 70, 235, 211, 167, 138, 104, 132, 248, 157, 65, 153, 216, 47, 125, 205, 237,
+            137, 220, 25, 228, 146, 194, 10, 169, 201, 224, 88, 119, 38, 140, 120, 125, 140, 46,
+            184, 221, 30, 10, 47, 34, 140, 173, 64, 38, 48, 77, 236, 206, 163, 111, 80, 46, 40,
+            232, 63, 247, 222, 25, 20, 246, 143, 9, 107, 172, 180, 84, 188, 234, 102, 87, 181, 173,
+            83, 14, 163, 170, 91, 29, 209, 93, 52, 158, 213, 6, 91, 71, 54, 244, 189, 198, 60, 21,
+            131, 210, 35, 18, 36, 164, 188, 87, 54, 73, 208, 115, 11, 248, 57, 107, 93, 23, 49,
+            129, 221, 61, 12, 172, 31, 199, 129, 196, 5, 184, 78, 226, 210, 83, 232, 153, 64, 17,
+            119, 243, 45, 73, 50, 129, 35, 94, 243, 146, 86, 136, 202, 86, 87, 97, 193, 59, 160,
+            181, 95, 150, 148, 117, 96, 31, 151, 97, 159, 53, 72, 171, 239, 210, 67, 207, 201, 109,
+            160, 230, 235, 176, 35, 235, 98, 128, 166, 195, 144, 200, 156, 7, 72, 242, 15, 95, 99,
+            69, 41, 219, 254, 244, 80, 158, 177, 64, 83, 11, 235, 98, 201, 130, 176, 119, 22, 214,
+            135, 215, 37, 65, 108, 91, 34, 94, 0, 153, 161, 87, 144, 177, 12, 122, 205, 11, 72,
+            233, 213, 63, 37, 12, 255, 235, 188, 194, 189, 65, 169, 185, 207, 131, 182, 243, 233,
+            30, 245, 39, 42, 188, 157, 28, 121, 231, 194, 121, 250, 121, 11, 28, 252, 98, 151, 238,
+            124, 56, 138, 106, 116, 187, 203, 21, 75, 239, 132, 19, 62, 43, 42, 12, 214, 87, 225,
+            217, 169, 134, 183, 193, 241, 175, 140, 36, 147, 248, 86, 6, 58, 212, 72, 112, 0, 56,
+            168, 128, 68, 253, 173, 225, 152, 167, 138, 254, 97, 123, 227, 163, 135, 198, 49, 49,
+            138, 249, 234, 245, 78, 150, 140, 170, 199, 41, 206, 246, 19, 117, 241, 27, 112, 102,
+            4, 94, 237, 30, 0, 68, 252, 163, 205, 10, 63, 146, 147, 37, 153, 197, 52, 162, 50, 250,
+            219, 130, 197, 3, 60, 246, 133, 83, 140, 103, 227, 50, 212, 121, 165, 114, 139, 225,
+            195, 145, 107, 249, 127, 194, 23, 112, 141, 242, 14, 218, 42, 131, 19, 245, 143, 73,
+            79, 194, 135, 224, 171, 249, 169, 129, 160, 153, 75, 66, 26, 12, 254, 180, 212, 229,
+            172, 134, 159, 122, 212, 219, 21, 29, 33, 11, 176, 149, 73, 169, 26, 150, 96, 133, 90,
+            217, 18, 37, 244, 48, 249, 4, 180, 129, 9, 45, 219, 106, 215, 28, 81, 118, 48, 98, 109,
+            167, 72, 107, 187, 78, 127, 251, 184, 170, 74, 57, 188, 91, 196, 229, 251, 70, 163, 68,
+            227, 238, 71, 115, 155, 246, 146, 97, 208, 21, 245, 62, 127, 47, 79, 131, 217, 41, 153,
+            52, 237, 159, 60, 98, 18, 169, 149, 6, 84, 135, 2, 45, 170, 165, 213, 201, 127, 23,
+            209, 2, 158, 235, 240, 195, 255, 76, 54, 189, 113, 50, 105, 230, 191, 217, 29, 46, 181,
+            80, 197, 60, 177, 243, 61, 52, 24, 140, 134, 147, 176, 198, 22, 92, 156, 217, 189, 134,
+            17, 122, 53, 49, 14, 87, 128, 99, 207, 123, 113, 169, 195, 206, 127, 211, 21, 216, 166,
+            18, 137, 110, 148, 70, 26, 54, 52, 113, 189, 45, 89, 254, 218, 247, 193, 71, 19, 153,
+            35, 179, 49, 237, 199, 176, 251, 143, 95, 115, 195, 3, 122, 161, 243, 220, 39, 102,
+            147, 134, 25, 172, 164, 167, 110, 123, 221, 177, 28, 236, 100, 165, 186, 179, 45, 189,
+            183, 76, 171, 127, 209, 108, 220, 83, 207, 136, 98, 54, 76, 37, 188, 57, 157, 204, 109,
+            150, 181, 110, 57, 5, 26, 168, 34, 11, 117, 3, 184, 147, 155, 122, 244, 251, 215, 1,
+            211, 226, 185, 214, 120, 206, 212, 75, 203, 174, 140, 20, 93, 93, 207, 28, 15, 122, 9,
+            83, 98, 107, 51, 202, 151, 220, 42, 95, 17, 141, 141, 201, 149, 253, 55, 169, 170, 237,
+            166, 92, 92, 20, 89, 124, 167, 102, 161, 87, 97, 88, 20, 245, 175, 32, 111, 0, 2, 192,
+            25, 63, 182, 10, 226, 165, 162, 223, 35, 243, 198, 189, 167, 137, 134, 207, 84, 240, 8,
+            95, 137, 31, 159, 58, 211, 161, 94, 150, 54, 188, 145, 253, 206, 156, 130, 121, 192,
+            221, 73, 249, 92, 91, 184, 211, 131, 206, 205, 183, 159, 195, 170, 47, 13, 131, 6, 132,
+            103, 121, 40, 252, 250, 251, 85, 253, 68, 66, 211, 24, 104, 48, 150, 176, 62, 201, 161,
+            93, 204, 120, 196, 159, 208, 199, 96, 228, 239, 29, 239, 128, 156, 14, 131, 25, 27,
+            157, 249, 253, 250, 193, 148, 133, 59, 138, 202, 239,
+        ];
+
+        let keyslot = Keyslot::new(host_key);
+        let encr_keyslot = keyslot.encrypt(&[0x17u8; 32], &cust_key).unwrap();
+
+        assert_eq!(encr_keyslot, exp_keyslot);
+    }
+
+    #[test]
+    fn test_keyslot_v2_constants() {
+        // Test V2 keyslot constants
+        assert_eq!(
+            KeyslotV2::SIZE,
+            1680,
+            "V2 keyslot size should be 1680 bytes"
+        );
+        assert_eq!(
+            KeyslotV2::PHKH_SIZE,
+            0x40,
+            "V2 PHKH size should be 64 bytes (SHA-512)"
+        );
+    }
+
+    #[test]
+    fn test_keyslot_v2_creation() {
+        let (_, ec_key, mlkem_key) = get_test_key_and_cert_hybrid();
+        let hybrid = HybridPKey::new(
+            ec_key.public_key().unwrap(),
+            mlkem_key.public_key().unwrap(),
+        )
+        .unwrap();
+
+        let keyslot = KeyslotV2::new(hybrid);
+
+        // Verify keyslot was created successfully
+        assert!(keyslot.ec_hostkey.public_key_to_der().is_ok());
+        assert!(keyslot.mlkem_hostkey.public_key_to_der().is_ok());
+    }
+
+    #[test]
+    fn test_keyslot_enum_v1_variant() {
+        let (_, host_key) = get_test_keys();
+        let keyslot = Keyslot::V1(KeyslotV1(host_key));
+
+        assert_eq!(keyslot.phkh_size(), KeyslotV1::PHKH_SIZE);
+        assert_eq!(keyslot.size(), KeyslotV1::SIZE);
+        assert!(matches!(keyslot, Keyslot::V1(_)));
+    }
+
+    #[test]
+    fn test_keyslot_enum_v2_variant() {
+        let (_, ec_key, mlkem_key) = get_test_key_and_cert_hybrid();
+        let hybrid = HybridPKey::new(
+            ec_key.public_key().unwrap(),
+            mlkem_key.public_key().unwrap(),
+        )
+        .unwrap();
+        let keyslot = Keyslot::V2(KeyslotV2::new(hybrid));
+
+        assert_eq!(keyslot.phkh_size(), KeyslotV2::PHKH_SIZE);
+        assert_eq!(keyslot.size(), KeyslotV2::SIZE);
+        assert!(matches!(keyslot, Keyslot::V2(_)));
+    }
+
+    #[test]
+    fn test_keyslot_from_hostkey_v1() {
+        let (_, ec_key) = get_test_keys();
+        let hostkey = HostKey::V1(ec_key);
+        let keyslot = Keyslot::new(hostkey);
+
+        assert!(matches!(keyslot, Keyslot::V1(_)));
+        assert_eq!(keyslot.size(), KeyslotV1::SIZE);
+    }
+
+    #[test]
+    fn test_keyslot_from_hostkey_v2() {
+        let (_, ec_key, mlkem_key) = get_test_key_and_cert_hybrid();
+        let hybrid = HybridPKey::new(
+            ec_key.public_key().unwrap(),
+            mlkem_key.public_key().unwrap(),
+        )
+        .unwrap();
+        let hostkey = HostKey::V2(hybrid);
+        let keyslot = Keyslot::new(hostkey);
+
+        assert!(matches!(keyslot, Keyslot::V2(_)));
+        assert_eq!(keyslot.size(), KeyslotV2::SIZE);
+    }
+
+    #[test]
+    fn test_keyslot_from_hybrid_public_key() {
+        let (_, ec_key, mlkem_key) = get_test_key_and_cert_hybrid();
+        let hybrid = HybridPKey::new(
+            ec_key.public_key().unwrap(),
+            mlkem_key.public_key().unwrap(),
+        )
+        .unwrap();
+
+        let keyslot: Keyslot = hybrid.into();
+        assert!(matches!(keyslot, Keyslot::V2(_)));
+    }
+
+    #[test]
+    fn test_keyslot_sizes() {
+        // Document the sizes for V1 and V2
+        assert_eq!(KeyslotV1::SIZE, 80, "V1 keyslot size");
+        assert_eq!(
+            KeyslotV2::SIZE,
+            1680,
+            "V2 keyslot size (includes ML-KEM ciphertext)"
+        );
+    }
 }

rust/pv/src/req/mod.rs

@@ -21,6 +21,7 @@ pub(crate) use ec_coord::get_pub_ecdh_points;
 pub use ec_coord::EcPubKeyCoord;
 pub use encrypt::{Aad, Encrypt};
 pub use header::RequestHdr;
-pub use hostkey::HostKey;
-pub use keyslot::{Keyslot, KeyslotV1};
+pub use hostkey::{HostKey, HybridPKey};
+#[expect(unused)]
+pub use keyslot::{Keyslot, KeyslotV1, KeyslotV2};
 pub use request::{BinReqValues, Request};