salsa20: add ECRYPT test vectors (#428)

Author: newpavlov

salsa20/tests/data/ecrypt.blb

@@ -0,0 +1,26 @@
+use cipher::{KeyIvInit, StreamCipher, StreamCipherSeek, blobby};
+use salsa20::Salsa20;
+
+static DATA: &[u8] = include_bytes!("data/ecrypt.blb");
+
+/// ECRYPT test vectors:
+/// https://github.com/das-labor/legacy/blob/master/microcontroller-2/arm-crypto-lib/testvectors/salsa20-256.64-verified.test-vectors
+#[test]
+fn salsa20_ecrypt() {
+    let test_vectors = blobby::Blob4Iterator::new(DATA).unwrap();
+    for test_vector in test_vectors {
+        let [key, iv, pos, expected] = test_vector.unwrap();
+
+        let key = key.try_into().unwrap();
+        let iv = iv.try_into().unwrap();
+        let pos = u32::from_be_bytes(pos.try_into().unwrap());
+
+        let mut c = Salsa20::new(key, iv);
+        c.seek(pos);
+
+        let mut buf = [0u8; 64];
+        c.apply_keystream(&mut buf);
+
+        assert_eq!(buf, expected);
+    }
+}