diff --git a/README.md b/README.md
index 0a423e1..a065bc9 100644
--- a/README.md
+++ b/README.md
@@ -74,11 +74,11 @@ FLAGS:
 
 OPTIONS:
     -p, --password <password>          Password used to derive encryption keys
-    -b, --block-size <blocksize>       Size of file chunk (in bytes) [default: 65536]
-    -c, --cipher <cipher>              Encryption cipher to use [possible values: aes, xchacha20]
+    -i, --iterations <iterations>      Argon2 time cost [default: 10]
     -m, --memory-cost <memory cost>    Argon2 memory cost (in kilobytes) [default: 4096]
     -t, --threads <threads>            Argon2 parallelism (between 1 and 255) [default: 4]
-    -i, --iterations <iterations>      Argon2 time cost [default: 10]
+    -b, --block-size <blocksize>       Size of the I/O buffer (in bytes) [default: 65536]
+    -c, --cipher <cipher>              Encryption cipher to use [possible values: aes, xchacha20]
 
 ARGS:
     <INPUT>     <PATH> | "-" or empty for stdin
diff --git a/src/cli.rs b/src/cli.rs
index 42d1d13..7143da3 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -67,7 +67,7 @@ pub fn parse() -> Option<CliArgs> {
             Arg::with_name("blocksize")
                 .short("b")
                 .long("block-size")
-                .help("Size of file chunk (in bytes)")
+                .help("Size of the I/O buffer (in bytes)")
                 .default_value("65536")
         )
         .arg(