From bf21ebaaae44b267cfefc87eee9608c09aab96b7 Mon Sep 17 00:00:00 2001
From: Will Dillon <william@housedillon.com>
Date: Thu, 4 Dec 2025 17:07:12 +0000
Subject: Getting closer to no-std being done

---
 src/no_std_identity.rs | 108 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100644 src/no_std_identity.rs

(limited to 'src/no_std_identity.rs')

diff --git a/src/no_std_identity.rs b/src/no_std_identity.rs
new file mode 100644
index 0000000..2a0018e
--- /dev/null
+++ b/src/no_std_identity.rs
@@ -0,0 +1,108 @@
+use bytes::Bytes;
+use crate::{NameString, crypto::{Keystore, PrivateKey, PublicKey, SharedSecret}};
+use tinyvec::ArrayVec;
+
+#[derive(PartialEq, Clone, Debug)]
+pub struct Identity {
+    pub private_key: PrivateKey,
+    pub hash_prefix: u32,
+    pub secrets: ArrayVec<[(u32, SharedSecret); 10]>,
+}
+
+impl Default for Identity {
+    fn default() -> Self {
+        let private_key = PrivateKey::default();
+        let hash_prefix = private_key.hash_prefix();
+
+        Self {
+            private_key,
+            hash_prefix,
+            secrets: Default::default()
+        }
+    }
+}
+
+#[derive(PartialEq, Clone, Debug)]
+pub struct StaticKeystore {
+    pub identities: ArrayVec<[Identity; 10]>,
+    pub groups: ArrayVec<[SharedSecret; 10]>,
+}
+
+impl Keystore for StaticKeystore {
+    fn decrypt_and_id_p2p(&self, _source: u8, _dest: u8, mac: u16, data: &Bytes) -> Option<(Bytes, u32, u32)> {
+        // Just brute-force all the secrets until one matches...
+        for identity in self.identities.iter() {
+            for (peer_prefix, secret) in identity.secrets.iter() {
+                let result = secret.mac_then_decrypt(mac, data);
+                if let Some(result) = result {
+                    return Some((result, identity.hash_prefix, *peer_prefix));
+                }
+            }
+        }
+        None
+    }
+
+    fn decrypt_and_id_group(&self, _group_hash_prefix: u8, mac: u16, data: &Bytes) -> Option<(Bytes, Option<NameString>)> {
+        for group in self.groups.iter() {
+            let result = group.mac_then_decrypt(mac, data);
+            if let Some(result) = result {
+                return Some((result, None));
+            }
+        }
+
+        None
+    }
+
+    fn decrypt_anon(&self, _dest: u8, pub_key: &PublicKey, mac: u16, data: &Bytes) -> Option<(Bytes, u32)> {
+        // For each identity, create a shared secret against the provided public key and check it.
+        for identity in self.identities.iter() {
+            let secret = identity.private_key.create_secret(pub_key);
+            let result = secret.mac_then_decrypt(mac, data);
+            if let Some(result) = result {
+                return Some((result, identity.hash_prefix));
+            }
+        }
+        None
+    }
+}
+
+#[derive(PartialEq, Debug, Clone)]
+pub struct StaticKeystoreInput {
+    pub identities: ArrayVec<[PrivateKey; 10]>,
+    pub contacts: ArrayVec<[PublicKey; 10]>,
+    pub groups: ArrayVec<[SharedSecret; 10]>,
+}
+
+impl StaticKeystoreInput {
+    pub fn compile(self) -> StaticKeystore {
+        let mut retval = StaticKeystore {
+            identities: ArrayVec::new(),
+            groups:     ArrayVec::new(),
+        };
+
+        for identity_in in self.identities {
+            let mut identity = Identity::default();
+            identity.private_key = identity_in;
+            identity.hash_prefix = PublicKey::from(&identity.private_key).hash_prefix();
+            for contact_in in self.contacts.iter() {
+                identity.secrets.push((contact_in.hash_prefix(), identity.private_key.create_secret(&contact_in)));
+            }
+
+            retval.identities.push(identity);
+        }
+
+        for group in self.groups.iter() {
+            retval.groups.push(group.clone());
+        }
+
+        retval
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_compile() {
+
+    }
+}
\ No newline at end of file
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