diff --git a/client/src/main.rs b/client/src/main.rs
index 9b56fc0..a3566fc 100644
--- a/client/src/main.rs
+++ b/client/src/main.rs
@@ -106,7 +106,7 @@ fn call_api<D: serde::Serialize>(
     let data_s = serde_json::to_string(&data)?;
     info!("body: {}", data_s);
     let signature = crypto::sign(config.secret.as_bytes(), data_s.as_bytes());
-    let signature = crypto::bytes_to_hex_str(&signature)?;
+    let signature = crypto::bytes_to_hex_str(&signature);
     let client = reqwest::Client::new();
     let url = format!("{}/record", config.host);
     Ok(if method == Method::POST {
diff --git a/crypto/src/lib.rs b/crypto/src/lib.rs
index 786895e..84d363a 100644
--- a/crypto/src/lib.rs
+++ b/crypto/src/lib.rs
@@ -55,10 +55,8 @@ use ring::{digest, hmac};
 type Result<T> = std::result::Result<T, Error>;
 
 /// Converts a byte slice to a lowercase hex string.
-pub fn bytes_to_hex_str(bytes: &[u8]) -> Result<String> {
-    let mut output = String::new();
-    bytes.write_hex(&mut output)?;
-    Ok(output)
+pub fn bytes_to_hex_str(bytes: &[u8]) -> String {
+    bytes.encode_hex::<String>()
 }
 
 /// Converts a hey string to a vec of bytes.