feat: Falcon 512 signature

src/dsa/rpo_falcon512/mod.rs

@@ -0,0 +1,60 @@
+use crate::{
+    hash::rpo::Rpo256,
+    utils::{
+        collections::Vec, ByteReader, ByteWriter, Deserializable, DeserializationError,
+        Serializable,
+    },
+    Felt, StarkField, Word, ZERO,
+};
+
+#[cfg(feature = "std")]
+mod ffi;
+
+mod error;
+mod keys;
+mod polynomial;
+mod signature;
+
+pub use error::FalconError;
+pub use keys::{KeyPair, PublicKey};
+pub use polynomial::Polynomial;
+pub use signature::Signature;
+
+// CONSTANTS
+// ================================================================================================
+
+// The Falcon modulus.
+const MODULUS: u16 = 12289;
+const MODULUS_MINUS_1_OVER_TWO: u16 = 6144;
+
+// The Falcon parameters for Falcon-512. This is the degree of the polynomial `phi := x^N + 1`
+// defining the ring Z_p[x]/(phi).
+const N: usize = 512;
+const LOG_N: usize = 9;
+
+/// Length of nonce used for key-pair generation.
+const NONCE_LEN: usize = 40;
+
+/// Number of filed elements used to encode a nonce.
+const NONCE_ELEMENTS: usize = 8;
+
+/// Public key length as a u8 vector.
+const PK_LEN: usize = 897;
+
+/// Secret key length as a u8 vector.
+const SK_LEN: usize = 1281;
+
+/// Signature length as a u8 vector.
+const SIG_LEN: usize = 626;
+
+/// Bound on the squared-norm of the signature.
+const SIG_L2_BOUND: u64 = 34034726;
+
+// TYPE ALIASES
+// ================================================================================================
+
+type SignatureBytes = [u8; NONCE_LEN + SIG_LEN];
+type PublicKeyBytes = [u8; PK_LEN];
+type SecretKeyBytes = [u8; SK_LEN];
+type NonceBytes = [u8; NONCE_LEN];
+type NonceElements = [Felt; NONCE_ELEMENTS];