diff --git a/sw/device/silicon_creator/lib/ownership/datatypes.h b/sw/device/silicon_creator/lib/ownership/datatypes.h
index d849f39ee97e43..88c745d6f2ff0b 100644
--- a/sw/device/silicon_creator/lib/ownership/datatypes.h
+++ b/sw/device/silicon_creator/lib/ownership/datatypes.h
@@ -17,6 +17,11 @@
 extern "C" {
 #endif  // __cplusplus
 
+typedef struct hybrid_key {
+  ecdsa_p256_public_key_t ecdsa;
+  sigverify_spx_key_t spx;
+} hybrid_key_t;
+
 /**
  * An owner_key can be either a ECDSA P256 or SPX+ key.  The type of the key
  * material will be determined by a separate field on the owner block
@@ -24,6 +29,10 @@ extern "C" {
 typedef union owner_key {
   /** ECDSA P256 public key */
   ecdsa_p256_public_key_t ecdsa;
+  /** SPHINCS+ public key */
+  sigverify_spx_key_t spx;
+  /** Hybrid ECDSA & SPHINCS+ public key */
+  hybrid_key_t hybrid;
   /** Enough space to hold an ECDSA key and a SPX+ key for hybrid schemes */
   uint32_t raw[16 + 8];
 } owner_key_t;
@@ -55,10 +64,24 @@ typedef enum ownership_key_alg {
   kOwnershipKeyAlgRsa = 0x33415352,
   /** Key algorithm ECDSA P-256: `P256` */
   kOwnershipKeyAlgEcdsaP256 = 0x36353250,
-  /** Key algorithm SPX+: `SPX+` */
-  kOwnershipKeyAlgSpx = 0x2b585053,
-  /** Key algorithm SPX+q20: `Sq20` */
-  kOwnershipKeyAlgSpxq20 = 0x30327153,
+  /** Key algorithm SPX+ Pure: `S+Pu` */
+  kOwnershipKeyAlgSpxPure = 0x75502b53,
+  /** Key algorithm SPX+ Prehashed SHA256: `S+S2` */
+  kOwnershipKeyAlgSpxPrehash = 0x32532b53,
+  /** Key algorithm Hybrid P256 & SPX+ Pure: `H+Pu` */
+  kOwnershipKeyAlgHybridSpxPure = 0x75502b48,
+  /** Key algorithm Hybrid P256 & SPX+ Prehashed SHA256: `H+S2` */
+  kOwnershipKeyAlgHybridSpxPrehash = 0x32532b48,
+
+  // Tentative identifiers for SPHINCS+ q20 variants (not yet supported):
+  // Key algorithm SPX+ Pure: `SqPu`
+  kOwnershipKeyAlgSq20Pure = 0x75507153,
+  // Key algorithm SPX+ Prehashed SHA256: `SqS2`
+  kOwnershipKeyAlgSq20Prehash = 0x32537153,
+  // Key algorithm Hybrid P256 & SPX+ Pure: `HqPu`
+  kOwnershipKeyAlgHybridSq20Pure = 0x75507148,
+  // Key algorithm Hybrid P256 & SPX+ Prehashed SHA256: `HqS2`
+  kOwnershipKeyAlgHybridSq20Prehash = 0x32537148,
 } ownership_key_alg_t;
 
 typedef enum ownership_update_mode {
@@ -224,6 +247,7 @@ typedef struct owner_application_key {
     sigverify_rsa_key_t rsa;
     sigverify_spx_key_t spx;
     ecdsa_p256_public_key_t ecdsa;
+    hybrid_key_t hybrid;
   } data;
 } owner_application_key_t;
 
@@ -242,6 +266,8 @@ enum {
       offsetof(owner_application_key_t, data) + sizeof(sigverify_spx_key_t),
   kTlvLenApplicationKeyEcdsa =
       offsetof(owner_application_key_t, data) + sizeof(ecdsa_p256_public_key_t),
+  kTlvLenApplicationKeyHybrid =
+      offsetof(owner_application_key_t, data) + sizeof(hybrid_key_t),
 };
 
 // clang-format off
diff --git a/sw/host/opentitanlib/src/ownership/misc.rs b/sw/host/opentitanlib/src/ownership/misc.rs
index e4b9f936df635c..a29bbcff819bcc 100644
--- a/sw/host/opentitanlib/src/ownership/misc.rs
+++ b/sw/host/opentitanlib/src/ownership/misc.rs
@@ -31,8 +31,10 @@ with_unknown! {
         Unknown = 0,
         Rsa = u32::from_le_bytes(*b"RSA3"),
         EcdsaP256 = u32::from_le_bytes(*b"P256"),
-        Spx = u32::from_le_bytes(*b"SPX+"),
-        Spxq20 = u32::from_le_bytes(*b"Sq20"),
+        SpxPure = u32::from_le_bytes(*b"S+Pu"),
+        SpxPrehash = u32::from_le_bytes(*b"S+S2"),
+        HybridSpxPure = u32::from_le_bytes(*b"H+Pu"),
+        HybridSpxPrehash = u32::from_le_bytes(*b"H+S2"),
     }
 }
 
@@ -130,6 +132,31 @@ impl TlvHeader {
     }
 }
 
+#[derive(Debug, Serialize, Deserialize)]
+pub struct HybridRawPublicKey {
+    #[serde(deserialize_with = "string_or_struct")]
+    pub ecdsa: EcdsaRawPublicKey,
+    #[serde(deserialize_with = "string_or_struct")]
+    pub spx: SpxRawPublicKey,
+}
+
+impl HybridRawPublicKey {
+    const SIZE: usize = EcdsaRawPublicKey::SIZE + SpxRawPublicKey::SIZE;
+
+    pub fn read(src: &mut impl Read) -> Result<Self> {
+        Ok(Self {
+            ecdsa: EcdsaRawPublicKey::read(src)?,
+            spx: SpxRawPublicKey::read(src)?,
+        })
+    }
+
+    pub fn write(&self, dest: &mut impl Write) -> Result<()> {
+        self.ecdsa.write(dest)?;
+        self.spx.write(dest)?;
+        Ok(())
+    }
+}
+
 /// Low-level key material (ie: bit representation).
 #[derive(Debug, Serialize, Deserialize)]
 #[allow(clippy::len_without_is_empty)]
@@ -142,6 +169,8 @@ pub enum KeyMaterial {
     Rsa(#[serde(deserialize_with = "string_or_struct")] RsaRawPublicKey),
     #[serde(alias = "spx")]
     Spx(#[serde(deserialize_with = "string_or_struct")] SpxRawPublicKey),
+    #[serde(alias = "hybrid")]
+    Hybrid(HybridRawPublicKey),
 }
 
 impl Default for KeyMaterial {
@@ -156,6 +185,7 @@ impl KeyMaterial {
             KeyMaterial::Ecdsa(_) => EcdsaRawPublicKey::SIZE,
             KeyMaterial::Rsa(_) => RsaRawPublicKey::SIZE,
             KeyMaterial::Spx(_) => SpxRawPublicKey::SIZE,
+            KeyMaterial::Hybrid(_) => HybridRawPublicKey::SIZE,
             KeyMaterial::Unknown(u) => u.len(),
         }
     }
@@ -164,7 +194,8 @@ impl KeyMaterial {
         match self {
             KeyMaterial::Ecdsa(_) => OwnershipKeyAlg::EcdsaP256,
             KeyMaterial::Rsa(_) => OwnershipKeyAlg::Rsa,
-            KeyMaterial::Spx(_) => OwnershipKeyAlg::Spx,
+            KeyMaterial::Spx(_) => OwnershipKeyAlg::SpxPure,
+            KeyMaterial::Hybrid(_) => OwnershipKeyAlg::HybridSpxPure,
             KeyMaterial::Unknown(_) => OwnershipKeyAlg::Unknown,
         }
     }
@@ -173,9 +204,12 @@ impl KeyMaterial {
         let result = match kind {
             OwnershipKeyAlg::Rsa => KeyMaterial::Rsa(RsaRawPublicKey::read(src)?),
             OwnershipKeyAlg::EcdsaP256 => KeyMaterial::Ecdsa(EcdsaRawPublicKey::read(src)?),
-            OwnershipKeyAlg::Spx | OwnershipKeyAlg::Spxq20 => {
+            OwnershipKeyAlg::SpxPure | OwnershipKeyAlg::SpxPrehash => {
                 KeyMaterial::Spx(SpxRawPublicKey::read(src)?)
             }
+            OwnershipKeyAlg::HybridSpxPure | OwnershipKeyAlg::HybridSpxPrehash => {
+                KeyMaterial::Hybrid(HybridRawPublicKey::read(src)?)
+            }
             _ => {
                 return Err(
                     Error::InvalidPublicKey(anyhow!("Unknown key algorithm {}", kind)).into(),
@@ -208,6 +242,7 @@ impl KeyMaterial {
             KeyMaterial::Ecdsa(k) => k.write(dest)?,
             KeyMaterial::Rsa(k) => k.write(dest)?,
             KeyMaterial::Spx(k) => k.write(dest)?,
+            KeyMaterial::Hybrid(k) => k.write(dest)?,
             _ => {
                 return Err(Error::InvalidPublicKey(anyhow!("Unknown key type")).into());
             }