Improve salt generation and checking

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "argon2-cli"
-version = "0.1.1"
+version = "0.2.0"
 edition = "2024"
 authors = [
     "Joel Schulz-Andres <joel@systemscape.de>",
@@ -21,11 +21,12 @@ eula = false
 
 [dependencies]
 argon2 = "0.5.3"
-clap = { version = "4.5.54", features = ["derive"] }
+clap = { version = "4.6.1", features = ["derive"] }
+rand_core = { version = "0.6", features = ["getrandom"] }
 hex = "0.4.3"
 
 [dev-dependencies]
-rand = { version = "0.9.2", features = ["std", "std_rng"] }
+rand = { version = "0.9.4", features = ["std", "std_rng"] }
 
 # The profile that 'dist' will build with
 [profile.dist]

README.md

@@ -5,21 +5,30 @@ Generate Argon2 hashes from command line
 ## Installation
 
 ```bash
-cargo install --path .
+cargo install argon2-cli
+```
+
+Or via [`cargo-binstall`](https://github.com/cargo-bins/cargo-binstall):
+
+```bash
+cargo binstall argon2-cli
 ```
 
 ## Usage
 
 ```bash
-echo -n "password" | argon2 somesalt
+echo -n "password" | argon2
 ```
 
+This CLI accepts the password via `stdin`, which avoids putting the password in shell history.
+
 ### Options
 
 ```
-argon2 [-h] salt [-i|-d|-id] [-t iterations] [-m log2(memory in KiB) | -k memory in KiB] [-p parallelism] [-l hash length] [-e|-r] [-v (10|13)]
+argon2 [-h] [salt] [-i|-d|-id] [-t iterations] [-m log2(memory in KiB) | -k memory in KiB] [-p parallelism] [-l hash length] [-e|-r] [-v (10|13)]
 ```
 
+- `[salt]` Optional explicit salt; must be at least 8 characters long
 - `-i` Use Argon2i (default)
 - `-d` Use Argon2d
 - `-id` Use Argon2id
@@ -35,7 +44,10 @@ argon2 [-h] salt [-i|-d|-id] [-t iterations] [-m log2(memory in KiB) | -k memory
 ## Examples
 
 ```bash
-# Basic usage
+# Basic usage (random salt generated automatically)
+echo -n "password" | argon2
+
+# With explicit salt
 echo -n "password" | argon2 somesalt
 
 # Use Argon2id with custom parameters
@@ -45,6 +57,10 @@ echo -n "password" | argon2 somesalt -id -t 4 -m 16 -p 4
 echo -n "password" | argon2 somesalt -e
 ```
 
+## Compatibility
+
+This CLI strives for interface compatibility with the [C reference implementation](https://github.com/P-H-C/phc-winner-argon2), but does not guarantee it. Deviations are made where the original interface significantly hinders usability. For example, the salt is optional in our implementation and a cryptographically secure random salt is generated by default. This CLI also accepts the password via `stdin`, unlike the standard Linux `argon2` CLI, which helps avoid leaking passwords into shell history.
+
 ## License
 
 MIT