diff --git a/src/pcd.rs b/src/pcd.rs
index ff93483..e493949 100644
--- a/src/pcd.rs
+++ b/src/pcd.rs
@@ -9,7 +9,7 @@ use serde_json::{Map, Value};
 use sp_client::{bitcoin::{hashes::{sha256t_hash_newtype, Hash, HashEngine}, hex::{DisplayHex, FromHex}, XOnlyPublicKey}, silentpayments::utils::SilentPaymentAddress};
 use tsify::Tsify;
 
-use crate::crypto::AAD;
+use crate::{crypto::AAD, signature::{AnkValidationNoHash, AnkValidationYesHash, Proof}};
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize, Tsify)]
 #[tsify(into_wasm_abi, from_wasm_abi)]
@@ -181,6 +181,67 @@ impl ValidationRule {
 
         Ok(res)
     }
+
+    pub fn is_satisfied(&self, field: &str, new_state_hash: AnkPcdHash, proofs: &[&Proof], members: &[Member]) -> bool {
+        // Check if this rule applies to the field
+        if !self.fields.contains(&field.to_string()) {
+            return false;
+        }
+
+        let required_members = (members.len() as f32 * self.quorum).ceil() as usize;
+        let validating_members = members.iter()
+            .filter(|member| {
+                let member_proofs: Vec<&Proof> = proofs.iter()
+                    .filter(|p| member.key_is_part_of_member(&p.get_key()))
+                    .cloned()
+                    .collect();
+                
+                self.satisfy_min_sig_member(member, new_state_hash, &member_proofs).is_ok()
+            })
+            .count();
+
+        validating_members >= required_members
+    }
+
+    pub fn satisfy_min_sig_member(&self, member: &Member, new_state_hash: AnkPcdHash, proofs: &[&Proof]) -> Result<()> {
+        let required_sigs = (member.get_addresses().len() as f32 * self.min_sig_member).ceil() as usize;
+        if required_sigs > proofs.len() {
+            // We can't have more proofs than registered devices for one member
+            return Err(Error::msg("More proofs than devices for member"));
+        } else if proofs.len() < required_sigs {
+            // Even if all proof are valid yes, we don't reach the quota
+            return Err(Error::msg("Not enough provided proofs to reach quota"));
+        }
+
+        let mut yes_votes: Vec<Proof> = Vec::new();
+        let mut no_votes: Vec<Proof> = Vec::new();
+
+        // Compute both yes and no commitment
+        let yes = AnkValidationYesHash::from_commitment(new_state_hash).to_byte_array();
+        let no = AnkValidationNoHash::from_commitment(new_state_hash).to_byte_array();
+
+        // Validate proofs here
+        for proof in proofs {
+            if !proof.verify().is_ok() {
+                return Err(Error::msg("Invalid proof"));
+            }
+
+            let signed_message = proof.get_message();
+
+            if signed_message == yes {
+                yes_votes.push(**proof);
+            } else if signed_message == no {
+                no_votes.push(**proof);
+            } else {
+                return Err(Error::msg("We don't know what this proof signs for"));
+            }
+        }
+        if yes_votes.len() >= required_sigs {
+            Ok(())
+        } else {
+            Err(Error::msg("Not enough yes votes"))
+        }
+    }
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, Tsify)]
@@ -190,6 +251,36 @@ pub struct RoleDefinition {
     pub validation_rules: Vec<ValidationRule>,
 }
 
+impl RoleDefinition {
+    pub fn is_satisfied(&self, new_state: &Value, previous_state: &Value, proofs: &[&Proof]) -> bool {
+        // compute the modified fields
+        let modified_fields: Vec<String> = new_state.as_object().unwrap()
+            .iter()
+            .filter_map(|(key, value)| {
+                let previous_value = previous_state.as_object().unwrap().get(key);
+                if previous_value.is_none() || value != previous_value.unwrap() {
+                    Some(key.clone())
+                } else {
+                    None
+                }
+            })
+            .collect();
+
+        let new_state_hash = AnkPcdHash::from_value(new_state);
+
+        // check that for each field we can satisfy at least one rule
+        modified_fields.iter().all(|field| {
+            self.validation_rules.iter().any(|rule| rule.is_satisfied(field, new_state_hash, proofs, &self.members))
+        })
+    }
+
+    pub fn get_applicable_rules(&self, field: &str) -> Vec<&ValidationRule> {
+        self.validation_rules.iter()
+            .filter(|rule| rule.fields.contains(&field.to_string()))
+            .collect()
+    }
+}
+
 pub fn compare_maps(map1: &Map<String, Value>, map2: &Map<String, Value>) -> bool {
     // First, check if both maps have the same keys
     if map1.keys().collect::<Vec<&String>>() != map2.keys().collect::<Vec<&String>>() {