diff --git a/Cargo.lock b/Cargo.lock
index 9b39bd2..189c268 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1449,6 +1449,7 @@ dependencies = [
  "parity-scale-codec",
  "polkavm",
  "revive-solidity",
+ "sha1",
 ]
 
 [[package]]
@@ -1698,6 +1699,17 @@ dependencies = [
  "stacker",
 ]
 
+[[package]]
+name = "sha1"
+version = "0.10.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3bf829a2d51ab4a5ddf1352d8470c140cadc8301b2ae1789db023f01cedd6ba"
+dependencies = [
+ "cfg-if",
+ "cpufeatures",
+ "digest 0.10.7",
+]
+
 [[package]]
 name = "sha2"
 version = "0.10.8"
diff --git a/Cargo.toml b/Cargo.toml
index 762df99..eaad105 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,6 +16,7 @@ serde_json = { version = "1.0", features = [ "arbitrary_precision" ] }
 regex = "1.10"
 once_cell = "1.19"
 num = "0.4"
+sha1 = "0.10"
 sha2 = "0.10"
 sha3 = "0.10"
 md5 = "0.7"
diff --git a/crates/integration/Cargo.toml b/crates/integration/Cargo.toml
index 210e510..eb53734 100644
--- a/crates/integration/Cargo.toml
+++ b/crates/integration/Cargo.toml
@@ -16,3 +16,4 @@ env_logger = { workspace = true }
 
 [dev-dependencies]
 alloy-sol-types = { workspace = true }
+sha1 = { workspace = true }
diff --git a/crates/integration/src/lib.rs b/crates/integration/src/lib.rs
index 49819f0..8aa59d5 100644
--- a/crates/integration/src/lib.rs
+++ b/crates/integration/src/lib.rs
@@ -41,6 +41,7 @@ pub fn compile_blob_with_options(
 mod tests {
     use alloy_primitives::{FixedBytes, Keccak256, I256, U256};
     use alloy_sol_types::{sol, SolCall};
+    use sha1::Digest;
 
     use crate::mock_runtime::{self, State};
 
@@ -244,7 +245,6 @@ mod tests {
             contract MStore8 {
                 function mStore8(uint value) public pure returns (uint256 word);
             }
-
         );
         let code = crate::compile_blob_with_options(
             "MStore8",
@@ -329,4 +329,31 @@ mod tests {
             assert(parameter, expected);
         }
     }
+
+    #[test]
+    fn sha1() {
+        sol!(
+            contract SHA1 {
+                function sha1(bytes memory data) public pure returns (bytes20);
+            }
+        );
+
+        let code =
+            crate::compile_blob_with_options("SHA1", include_str!("../contracts/sha1.sol"), false);
+        let (mut instance, export) = mock_runtime::prepare(&code, None);
+
+        let pre = vec![0xffu8; 512];
+        let mut hasher = sha1::Sha1::new();
+        hasher.update(&pre);
+        let hash = hasher.finalize();
+
+        let input = SHA1::sha1Call::new((pre,)).abi_encode();
+        let state = crate::mock_runtime::call(State::new(input), &mut instance, export);
+
+        assert_eq!(state.output.flags, 0);
+
+        let expected = FixedBytes::<20>::from_slice(&hash[..]);
+        let received = FixedBytes::<20>::from_slice(&state.output.data[..20]);
+        assert_eq!(received, expected);
+    }
 }
diff --git a/crates/integration/src/mock_runtime.rs b/crates/integration/src/mock_runtime.rs
index c803ad3..dacb388 100644
--- a/crates/integration/src/mock_runtime.rs
+++ b/crates/integration/src/mock_runtime.rs
@@ -58,7 +58,7 @@ fn link_host_functions(engine: &Engine) -> Linker<State> {
             |caller: Caller<State>, out_ptr: u32, out_len_ptr: u32| -> Result<(), Trap> {
                 let (mut caller, state) = caller.split();
 
-                assert_ne!(0, caller.read_u32(out_len_ptr)?);
+                assert!(state.input.len() <= caller.read_u32(out_len_ptr).unwrap() as usize);
 
                 caller.write_memory(out_ptr, &state.input)?;
                 caller.write_memory(out_len_ptr, &(state.input.len() as u32).encode())?;
diff --git a/crates/llvm-context/src/eravm/context/function/runtime/entry.rs b/crates/llvm-context/src/eravm/context/function/runtime/entry.rs
index 8bbd38e..c37a813 100644
--- a/crates/llvm-context/src/eravm/context/function/runtime/entry.rs
+++ b/crates/llvm-context/src/eravm/context/function/runtime/entry.rs
@@ -28,13 +28,16 @@ impl Entry {
     /// The number of mandatory arguments.
     pub const MANDATORY_ARGUMENTS_COUNT: usize = 2;
 
+    /// Reserve 1kb for calldata.
+    pub const MAX_CALLDATA_SIZE: usize = 1024;
+
     /// Initializes the global variables.
     /// The pointers are not initialized, because it's not possible to create a null pointer.
     pub fn initialize_globals<D>(context: &mut Context<D>) -> anyhow::Result<()>
     where
         D: Dependency + Clone,
     {
-        let calldata_type = context.array_type(context.byte_type(), 1024);
+        let calldata_type = context.array_type(context.byte_type(), Self::MAX_CALLDATA_SIZE);
         context.set_global(
             crate::eravm::GLOBAL_CALLDATA_POINTER,
             calldata_type,
@@ -112,7 +115,10 @@ impl Entry {
             "length_pointer_casted",
         )?;
 
-        context.build_store(length_pointer, context.integer_const(32, 1024))?;
+        context.build_store(
+            length_pointer,
+            context.integer_const(32, Self::MAX_CALLDATA_SIZE as u64),
+        )?;
         context.builder().build_call(
             context.module().get_function("input").expect("is declared"),
             &[input_pointer_casted.into(), length_pointer_casted.into()],