diff --git a/Cargo.lock b/Cargo.lock
index f981de29e..840a2d2f4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -290,6 +290,7 @@ dependencies = [
  "cfg-if",
  "cpufeatures",
  "digest",
+ "hex",
  "hex-literal",
 ]
 
diff --git a/sha1/Cargo.toml b/sha1/Cargo.toml
index 34c078b61..882d19e8d 100644
--- a/sha1/Cargo.toml
+++ b/sha1/Cargo.toml
@@ -21,6 +21,7 @@ cpufeatures = "0.3"
 
 [dev-dependencies]
 digest = { version = "0.11", features = ["dev"] }
+hex = "0.4.3"
 hex-literal = "1"
 
 [features]
diff --git a/sha1/tests/mod.rs b/sha1/tests/mod.rs
index 92858ae3f..e1fd8433b 100644
--- a/sha1/tests/mod.rs
+++ b/sha1/tests/mod.rs
@@ -1,10 +1,24 @@
 use digest::dev::{feed_rand_16mib, fixed_reset_test};
 use hex_literal::hex;
 use sha1::{Digest, Sha1};
+use std::fs;
+use std::path::Path;
+use std::time::{SystemTime, UNIX_EPOCH};
 
 digest::new_test!(sha1_kat, Sha1, fixed_reset_test);
 digest::hash_serialization_test!(sha1_serialization, Sha1);
 
+fn sha1_hex(bytes: &[u8]) -> String {
+    let mut hasher = Sha1::new();
+    hasher.update(bytes);
+    hex::encode(hasher.finalize())
+}
+
+fn sha1_file_hex(path: impl AsRef<Path>) -> std::io::Result<String> {
+    let bytes = fs::read(path)?;
+    Ok(sha1_hex(&bytes))
+}
+
 #[test]
 fn sha1_rand() {
     let mut h = Sha1::new();
@@ -14,3 +28,63 @@ fn sha1_rand() {
         hex!("7e565a25a8b123e9881addbcedcd927b23377a78"),
     );
 }
+
+///
+/// Test vectors from https://www.nist.gov/itl/ssd/software-quality-group/nsrl-test-data for SHA-1.
+///
+
+/// A file containing the ASCII string "abc" results in a 160 bit message digest of
+/// a9993e364706816aba3e25717850c26c9cd0d89d
+#[test]
+fn abc_file_has_expected_sha1_digest() {
+    let unique = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .expect("system time should be after the unix epoch")
+        .as_nanos();
+    let path = std::env::temp_dir().join(format!("tester-sha1-{unique}.txt"));
+
+    fs::write(&path, b"abc").expect("should write test file");
+    let digest = sha1_file_hex(&path).expect("should hash test file");
+
+    let _ = fs::remove_file(&path);
+
+    assert_eq!(digest, "a9993e364706816aba3e25717850c26c9cd0d89d");
+}
+
+/// A file containing the ASCII string "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"
+/// results in a 160-bit message digest of 84983e441c3bd26ebaae4aa1f95129e5e54670f1.
+#[test]
+fn long_test_vector_file_has_expected_sha1_digest() {
+    let unique = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .expect("system time should be after the unix epoch")
+        .as_nanos();
+    let path = std::env::temp_dir().join(format!("tester-sha1-{unique}.txt"));
+    let contents = b"abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq";
+
+    fs::write(&path, contents).expect("should write test file");
+    let digest = sha1_file_hex(&path).expect("should hash test file");
+
+    let _ = fs::remove_file(&path);
+
+    assert_eq!(digest, "84983e441c3bd26ebaae4aa1f95129e5e54670f1");
+}
+
+/// A file containing the binary-coded form of the ASCII string which consists of 1,000,000 repetitions of the character "a" results
+/// in a SHA-1 message digest of 34aa973cd4c4daa4f61eeb2bdbad27316534016f.
+#[test]
+fn one_million_a_file_has_expected_sha1_digest() {
+    let unique = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .expect("system time should be after the unix epoch")
+        .as_nanos();
+    let path = std::env::temp_dir().join(format!("tester-sha1-{unique}.txt"));
+    let bytes: Vec<u8> = std::iter::repeat(b'a').take(1_000_000).collect();
+
+    fs::write(&path, bytes).expect("should write test file");
+    let digest = sha1_file_hex(&path).expect("should hash test file");
+
+    let _ = fs::remove_file(&path);
+
+    assert_eq!(digest, "34aa973cd4c4daa4f61eeb2bdbad27316534016f");
+}