feat: improve uniformity & bump version

Author: GabrielePicco

Cargo.lock

@@ -3,7 +3,7 @@ resolver = "2"
 members = ["api", "program", "src", "vrf", "vrf-oracle", "vrf-cli", "sdk"]
 
 [workspace.package]
-version = "0.1.0"
+version = "0.1.1"
 edition = "2021"
 license = "Business Source License 1.1"
 authors = ["MagicBlock Labs <dev@magicblock.xyz>"]
@@ -14,9 +14,9 @@ readme = "./README.md"
 keywords = ["solana", "vrf", "ephemeral-rollups", "magicblock"]
 
 [workspace.dependencies]
-ephemeral-vrf = { path = "./vrf", version = "0.1.0" }
-ephemeral-vrf-api = { path = "./api", version = "0.1.0" }
-ephemeral-vrf-sdk-vrf-macro = { path = "sdk/vrf-macro", version = "0.1.0" }
+ephemeral-vrf = { path = "./vrf", version = "0.1.1" }
+ephemeral-vrf-api = { path = "./api", version = "0.1.1" }
+ephemeral-vrf-sdk-vrf-macro = { path = "sdk/vrf-macro", version = "0.1.1" }
 ephemeral-rollups-sdk = "0.2.4"
 borsh = ">=0.10.1"
 bytemuck = "1.14"

Cargo.toml

@@ -6,7 +6,7 @@ use anchor_lang::solana_program::hash::hash;
 use anchor_lang::solana_program::sysvar::slot_hashes;
 use ephemeral_vrf_sdk::anchor::{vrf, VrfProgram};
 use ephemeral_vrf_sdk::instructions::create_request_randomness_ix;
-use ephemeral_vrf_sdk::rnd::random_u32;
+use ephemeral_vrf_sdk::rnd::{random_u32, random_u8_with_range, random_bool};
 use ephemeral_vrf_sdk::consts::IDENTITY;
 use ephemeral_vrf_sdk::instructions::RequestRandomnessParams;
 use anchor_lang::solana_program::program::invoke_signed;
@@ -75,7 +75,9 @@ pub mod use_randomness {
             ctx.accounts.vrf_program_identity.is_signer
         );
         // We can safely consume the randomness
-        msg!("Consuming random number: {:?}", random_u32(&randomness));
+        msg!("Consuming random u32: {:?}", random_u32(&randomness));
+        msg!("Consuming random u8 (range 1-6): {:?}", random_u8_with_range(&randomness, 1, 6));
+        msg!("Consuming random bool: {:?}", random_bool(&randomness));
         Ok(())
     }
 }

program/tests/integration/use-randomness/Cargo.lock

@@ -8,7 +8,38 @@
 ///
 /// A random u8 value derived from the input bytes
 pub fn random_u8(bytes: &[u8; 32]) -> u8 {
-    bytes[0]
+    bytes[30]
+}
+
+/// Generates a random u8 value within a specified range from a 32-byte random seed
+///
+/// # Arguments
+///
+/// * `bytes` - A 32-byte array containing random data from the VRF
+/// * `min_value` - The minimum value (inclusive) of the desired range
+/// * `max_value` - The maximum value (inclusive) of the desired range
+///
+/// # Returns
+///
+/// A random u8 value uniformly distributed in the range [min_value, max_value]
+///
+/// # Algorithm
+///
+/// To avoid modulo bias, the function scans through the input bytes looking for
+/// a value that falls within an evenly divisible range. If no such value is found,
+/// it falls back to a slightly biased approach using the last byte.
+pub fn random_u8_with_range(bytes: &[u8; 32], min_value: u8, max_value: u8) -> u8 {
+    let range = (max_value - min_value + 1) as u16;
+    let threshold = (256 / range * range) as u8;
+
+    // Try to find a byte that, when mapped, gives an unbiased result
+    for &b in bytes.iter().rev() {
+        if b < threshold {
+            return min_value + (b % range as u8);
+        }
+    }
+    // Fallback (slight bias, but rare fallback case)
+    min_value + (bytes[31] % range as u8)
 }
 
 /// Generates a random u32 value from a 32-byte random seed
@@ -21,7 +52,7 @@ pub fn random_u8(bytes: &[u8; 32]) -> u8 {
 ///
 /// A random u32 value derived from the input bytes
 pub fn random_u32(bytes: &[u8; 32]) -> u32 {
-    u32::from_le_bytes([bytes[0], bytes[3], bytes[7], bytes[12]])
+    u32::from_le_bytes([bytes[28], bytes[29], bytes[30], bytes[31]])
 }
 
 /// Generates a random i32 value from a 32-byte random seed
@@ -75,5 +106,5 @@ pub fn random_i64(bytes: &[u8; 32]) -> i64 {
 ///
 /// A random boolean value (true or false) derived from the input bytes
 pub fn random_bool(bytes: &[u8; 32]) -> bool {
-    (bytes[0] & 1) == 1
+    (bytes[31] % 2) == 0
 }

program/tests/integration/use-randomness/programs/use-randomness/src/lib.rs

@@ -1,7 +1,7 @@
 [package]
 name = "ephemeral-vrf-oracle"
-version = "0.1.0"
-edition = "2021"
+version = {workspace = true}
+edition = {workspace = true}
 
 [[bin]]
 name = "ephemeral_vrf"

sdk/src/rnd.rs

@@ -1,10 +1,10 @@
 
 [package]
 name = "vrf-oracle"
-version = "0.1.0"
-edition = "2021"
-description = "Oracle client for EphemeralVrf"
-authors = ["Magicblock Labs"]
+version = { workspace = true }
+edition = { workspace = true }
+description = "Ephemeral VRF Oracle"
+authors = { workspace = true }
 
 [dependencies]
 clap.workspace = true