diff --git a/src/get.rs b/src/get.rs
index a5a2fc2..c5547a8 100644
--- a/src/get.rs
+++ b/src/get.rs
@@ -7,7 +7,7 @@ use crate::content::read;
 use crate::errors::Error;
 use crate::index::{self, Entry};
 
-pub fn read(cache: &Path, key: String) -> Result<Vec<u8>, Error> {
+pub fn read(cache: &Path, key: &str) -> Result<Vec<u8>, Error> {
     if let Some(entry) = index::find(&cache, &key)? {
         read_hash(cache, &entry.integrity)
     } else {
@@ -19,7 +19,7 @@ pub fn read_hash(cache: &Path, sri: &Integrity) -> Result<Vec<u8>, Error> {
     Ok(read::read(cache, sri)?)
 }
 
-pub fn copy(cache: &Path, key: String, to: &Path) -> Result<u64, Error> {
+pub fn copy(cache: &Path, key: &str, to: &Path) -> Result<u64, Error> {
     if let Some(entry) = index::find(&cache, &key)? {
         copy_hash(cache, &entry.integrity, to)
     } else {
@@ -31,7 +31,7 @@ pub fn copy_hash(cache: &Path, sri: &Integrity, to: &Path) -> Result<u64, Error>
     Ok(read::copy(cache, sri, to)?)
 }
 
-pub fn info(cache: &Path, key: String) -> Result<Option<Entry>, Error> {
+pub fn info(cache: &Path, key: &str) -> Result<Option<Entry>, Error> {
     index::find(cache, &key)
 }
 
diff --git a/src/put.rs b/src/put.rs
index 3574b01..049c341 100644
--- a/src/put.rs
+++ b/src/put.rs
@@ -9,7 +9,7 @@ use crate::content::write;
 use crate::index;
 use crate::errors::Error;
 
-pub fn data(cache: &Path, key: String, data: Vec<u8>) -> Result<Integrity, Error> {
+pub fn data(cache: &Path, key: &str, data: Vec<u8>) -> Result<Integrity, Error> {
     let sri = write::write(&cache, &data)?;
     Writer::new(cache, &key).integrity(sri).commit(data)
 }