fix comment

Author: tcoratger

src/lean_spec/subspecs/xmss/interface.py

@@ -17,7 +17,7 @@ def key_gen(
     activation_epoch: int, num_active_epochs: int
 ) -> Tuple[PublicKey, SecretKey]:
     """
-    Generates a new cryptographic key pair.
+    Generates a new cryptographic key pair. This is a **randomized** algorithm.
 
     This function is a placeholder. In a real implementation, it would involve
     generating a master secret, deriving all one-time keys, and constructing
@@ -41,7 +41,8 @@ def key_gen(
 
 def sign(sk: SecretKey, epoch: int, message: bytes) -> Signature:
     """
-    Produces a digital signature for a given message at a specific epoch.
+    Produces a digital signature for a given message at a specific epoch. This
+    is a **randomized** algorithm.
 
     This function is a placeholder. The signing process involves encoding the
     message, generating a one-time signature, and providing a Merkle path.
@@ -62,7 +63,8 @@ def sign(sk: SecretKey, epoch: int, message: bytes) -> Signature:
 
 def verify(pk: PublicKey, epoch: int, message: bytes, sig: Signature) -> bool:
     r"""
-    Verifies a digital signature against a public key, message, and epoch.
+    Verifies a digital signature against a public key, message, and epoch. This
+    is a **deterministic** algorithm.
 
     This function is a placeholder. The complete verification logic is detailed
     below and will be implemented in a future update.

src/lean_spec/subspecs/xmss/structures.py

@@ -1,23 +1,29 @@
 """Defines the data structures for the Generalized XMSS signature scheme."""
 
-from typing import List
+from typing import Annotated, List
 
 from pydantic import BaseModel, ConfigDict, Field
 
 from ..koalabear import Fp
 from .constants import HASH_LEN_FE, PARAMETER_LEN, RAND_LEN_FE
 
-HashDigest = List[Fp]
+HashDigest = Annotated[
+    List[Fp], Field(min_length=HASH_LEN_FE, max_length=HASH_LEN_FE)
+]
 """
 A type alias representing a hash digest.
 """
 
-Parameter = List[Fp]
+Parameter = Annotated[
+    List[Fp], Field(min_length=PARAMETER_LEN, max_length=PARAMETER_LEN)
+]
 """
 A type alias representing the public parameter `P`.
 """
 
-Randomness = List[Fp]
+Randomness = Annotated[
+    List[Fp], Field(min_length=RAND_LEN_FE, max_length=RAND_LEN_FE)
+]
 """
 A type alias representing the randomness `rho`.
 """
@@ -55,7 +61,7 @@ class Signature(BaseModel):
     rho: Randomness = Field(
         ..., max_length=RAND_LEN_FE, min_length=RAND_LEN_FE
     )
-    hashes: List[List[Fp]]
+    hashes: List[HashDigest]
 
 
 class SecretKey(BaseModel):