refactor and cleanup for v0.2.0

.travis.yml

@@ -7,6 +7,7 @@ go:
   - 1.9
 
 script:
+  - go test -v ./...
   - go get github.com/mitchellh/gox
   - CGO_ENABLED=0 gox -ldflags "-s" -rebuild
 

CHANGELOG

@@ -0,0 +1,10 @@
+* Mon Nov 20 2017 cornfeedhobo 0.2.0
+- Refactor key management to a struct-based approach
+- Drop printing to stdout and switch to writing files like OpenSSH's ssh-keygen
+- Refactor resource names
+- Style clean up
+- Add configurable work factor
+- Add tests
+
+* Sun Nov 12 2017 cornfeedhobo 0.1.0
+- initial draft

README.md

@@ -1,32 +1,52 @@
 ssh-keydgen [![Travis](https://img.shields.io/travis/cornfeedhobo/ssh-keydgen.svg)]() [![Github All Releases](https://img.shields.io/github/downloads/cornfeedhobo/ssh-keydgen/total.svg)]()
 ===========
 
-Generate _Deterministic_ SSH keys
-
-## Usage
+ Generate _Deterministic_ SSH keys
+
    ```text
    NAME:
-      ssh-keydgen - deterministic authentication key generation
+      ssh-keydgen - Deterministic authentication key generation
    
    USAGE:
-      ssh-keydgen [-t] [-b] [-c] [-o] [-a]
+      ssh-keydgen [-t] [-b] [-c] [-n] [-f] [-a]
    
    AUTHOR:
       cornfeedhobo
    
    OPTIONS:
-      -t type   Specifies the type of key to create. The possible values are “dsa”, “ecdsa”, “ed25519”, or “rsa”. (default: "ed25519")
-      -b bits   Specifies the number of bits in the key to create. Possible values are restricted by key type. (default: 2048)
-      -c curve  Specifies the elliptic curve to use. The possible values are 256, 384, or 521. (default: 256)
-      -o path   Specifies the path to output the generated key.
-      -a        Add the generated key to the running ssh-agent.
+      -t type      Specifies the type of key to create. The possible values are "dsa", "ecdsa", "rsa", or "ed25519". (default: "ed25519")
+      -b bits      Specifies the number of bits in the key to create. Possible values are restricted by key type. (default: 2048)
+      -c curve     Specifies the elliptic curve to use. The possible values are 256, 384, or 521. (default: 256)
+      -n factor    Specifies the work factor, or "difficulty", applied to the key generation function. (default: 16384)
+      -f filename  Specifies the filename of the key file.
+      -a           Add the generated key to the running ssh-agent.
 
    COPYRIGHT:
       (c) 2017 cornfeedhobo
    ```
 
 
 
+## Usage
+
+ 1) Generate your keys
+    ```bash
+    keydgen -f deterministic_key
+    ls -lh deterministic_key*
+    ```
+
+ 2) Allow time to pass, hoping an emergency does not arise when you have no access to your keys ...
+
+    _If_ the time comes where you need access but can't get to your keys, you can then obtain this
+    utility and re-generate, or even directly add your key to a running `ssh-agent`.
+    ```bash
+    keydgen -a
+    ```
+    
+ 3) Profit!
+
+
+
 ## Is it any good?
 
-[Yes](http://news.ycombinator.com/item?id=3067434)
+ [Yes](http://news.ycombinator.com/item?id=3067434)

deterministic.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"crypto/sha512"
+
+	"golang.org/x/crypto/ripemd160"
+	"golang.org/x/crypto/scrypt"
+)
+
+var WorkFactor int
+
+type Deterministic struct {
+	seed []byte
+	salt []byte
+}
+
+func (d *Deterministic) Read(p []byte) (int, error) {
+
+	var sha = sha512.New()
+	if _, err := sha.Write(d.seed); err != nil {
+		return 0, err
+	}
+	d.seed = sha.Sum(nil)
+
+	var ripe = ripemd160.New()
+	if _, err := ripe.Write(d.salt); err != nil {
+		return 0, err
+	}
+	d.salt = ripe.Sum(nil)
+
+	dk, err := scrypt.Key(d.seed, d.salt, WorkFactor, 8, 1, len(p))
+	if err != nil {
+		return 0, err
+	}
+	return copy(p, dk), nil
+
+}