diff --git a/powersoftau/src/bin/beacon_constrained.rs b/powersoftau/src/bin/beacon_constrained.rs
index 8cd16d0..6b89185 100644
--- a/powersoftau/src/bin/beacon_constrained.rs
+++ b/powersoftau/src/bin/beacon_constrained.rs
@@ -21,14 +21,15 @@ const CHECK_INPUT_CORRECTNESS: CheckForCorrectness = CheckForCorrectness::No;
 #[allow(clippy::modulo_one)]
 fn main() {
     let args: Vec<String> = std::env::args().collect();
-    if args.len() != 5 {
-        println!("Usage: \n<challenge_file> <response_file> <circuit_power> <batch_size>");
+    if args.len() != 6 {
+        println!("Usage: \n<challenge_file> <response_file> <circuit_power> <batch_size> <beacon_hash>");
         std::process::exit(exitcode::USAGE);
     }
     let challenge_filename = &args[1];
     let response_filename = &args[2];
     let circuit_power = args[3].parse().expect("could not parse circuit power");
     let batch_size = args[4].parse().expect("could not parse batch size");
+    let beacon_hash = args[5];
 
     let parameters = CeremonyParams::<Bn256>::new(circuit_power, batch_size);
 
@@ -49,9 +50,7 @@ fn main() {
         use rand::chacha::ChaChaRng;
         use rand::SeedableRng;
 
-        // Place block hash here (block number #564321)
-        let mut cur_hash: [u8; 32] =
-            hex!("0000000000000000000a558a61ddc8ee4e488d647a747fe4dcc362fe2026c620");
+        let mut cur_hash: [u8; 32] = hex!(beacon_hash);
 
         // Performs 2^n hash iterations over it
         const N: u64 = 10;