Added HMAC example.

2 files changed, 23 insertions, 0 deletions

diff --git a/examples/stm32f7/Cargo.toml b/examples/stm32f7/Cargo.toml
index a612c2554..736e81723 100644
--- a/examples/stm32f7/Cargo.toml
+++ b/examples/stm32f7/Cargo.toml
@@ -29,6 +29,7 @@ critical-section = "1.1"
 embedded-storage = "0.3.1"
 static_cell = "2"
 sha2 = { version = "0.10.8", default-features = false }
+hmac = "0.12.1"
 
 [profile.release]
 debug = 2
diff --git a/examples/stm32f7/src/bin/hash.rs b/examples/stm32f7/src/bin/hash.rs
index cbb880353..c2d1a7158 100644
--- a/examples/stm32f7/src/bin/hash.rs
+++ b/examples/stm32f7/src/bin/hash.rs
@@ -6,9 +6,12 @@ use embassy_executor::Spawner;
 use embassy_stm32::hash::*;
 use embassy_stm32::{bind_interrupts, hash, peripherals, Config};
 use embassy_time::Instant;
+use hmac::{Hmac, Mac};
 use sha2::{Digest, Sha256};
 use {defmt_rtt as _, panic_probe as _};
 
+type HmacSha256 = Hmac<Sha256>;
+
 bind_interrupts!(struct Irqs {
     HASH_RNG => hash::InterruptHandler<peripherals::HASH>;
 });
@@ -52,5 +55,24 @@ async fn main(_spawner: Spawner) -> ! {
     info!("Software Execution Time: {:?}", sw_execution_time);
     assert_eq!(hw_digest, sw_digest[..]);
 
+    let hmac_key: [u8; 64] = [0x55; 64];
+
+    // Compute HMAC in hardware.
+    let mut sha256hmac_context = hw_hasher.start(Algorithm::SHA256, DataType::Width8, Some(&hmac_key));
+    hw_hasher.update(&mut sha256hmac_context, test_1).await;
+    hw_hasher.update(&mut sha256hmac_context, test_2).await;
+    let mut hw_hmac: [u8; 32] = [0; 32];
+    hw_hasher.finish(sha256hmac_context, &mut hw_hmac).await;
+
+    // Compute HMAC in software.
+    let mut sw_mac = HmacSha256::new_from_slice(&hmac_key).unwrap();
+    sw_mac.update(test_1);
+    sw_mac.update(test_2);
+    let sw_hmac = sw_mac.finalize().into_bytes();
+
+    info!("Hardware HMAC: {:?}", hw_hmac);
+    info!("Software HMAC: {:?}", sw_hmac[..]);
+    assert_eq!(hw_hmac, sw_hmac[..]);
+
     loop {}
 }