diff --git a/src/cmd_signfile.rs b/src/cmd_signfile.rs
index c1d9167..4c85d21 100644
--- a/src/cmd_signfile.rs
+++ b/src/cmd_signfile.rs
@@ -14,7 +14,7 @@ use crate::digest::sha256_bytes;
 use crate::util::base64_encode;
 
 pub const SIMPLE_SIG_V1: &str = "v1";
-pub const SIMPLE_SIG_SPECIFICATION: &str = "https://openwebstandard.org/simple-sign-file/v1";
+pub const SIMPLE_SIG_SCHEMA: &str = "https://openwebstandard.org/simple-sign-file/v1";
 pub const HASH_ALGORITHM_SHA256: &str = "sha256";
 pub const SIGNATURE_ALGORITHM_SHA256_WITH_ECDSA: &str = "SHA256withECDSA";
 pub const CERTIFICATES_SEARCH_URL: &str = "https://hatter.ink/ca/fetch_certificates.json?fingerprint=";
@@ -111,7 +111,7 @@ pub struct SimpleSignFileSignature {
 
 #[derive(Serialize)]
 pub struct SimpleSignFile {
-    pub specification: String,
+    pub schema: String,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub filename: Option<String>,
     pub digest: String,
@@ -127,7 +127,7 @@ pub struct CommandImpl;
 
 // Format:
 // {
-//   "specification": "https://openwebstandard.org/simple-sign-file/v1",
+//   "schema": "https://openwebstandard.org/simple-sign-file/v1",
 //   "version": "v1",
 //   "filename": "example.zip",
 //   "digest": "sha256-HEX(SHA256(filename-content))",
@@ -149,7 +149,8 @@ impl Command for CommandImpl {
     fn subcommand<'a>(&self) -> App<'a, 'a> {
         SubCommand::with_name(self.name()).about("PIV Sign(with SHA256) subcommand")
             .arg(Arg::with_name("pin").short("p").long("pin").takes_value(true).help("PIV card user pin"))
-            .arg(Arg::with_name("slot").short("s").long("slot").takes_value(true).required(true).help("PIV slot, e.g. 82, 83 ... 95, 9a, 9c, 9d, 9e"))
+            .arg(Arg::with_name("slot").short("s").long("slot")
+                .takes_value(true).required(true).help("PIV slot, e.g. 82, 83 ... 95, 9a, 9c, 9d, 9e"))
             .arg(Arg::with_name("file").short("f").long("file").takes_value(true).required(true).help("Input file"))
             .arg(Arg::with_name("filename").short("n").long("filename").takes_value(true).help("Filename"))
             .arg(Arg::with_name("comment").short("c").long("comment").takes_value(true).help("Comment"))
@@ -214,7 +215,7 @@ impl Command for CommandImpl {
             certificates,
         };
         let simple_sig = SimpleSignFile {
-            specification: SIMPLE_SIG_SPECIFICATION.to_string(),
+            schema: SIMPLE_SIG_SCHEMA.to_string(),
             filename: sign_file_request.filename.clone(),
             digest: format!("{}-{}", HASH_ALGORITHM_SHA256, hex::encode(&sign_file_request.digest)),
             timestamp: sign_file_request.timestamp,