initial commit with ecdsa working

main.go

@@ -0,0 +1,163 @@
+package main
+
+import (
+  "flag"
+  "fmt"
+  "io"
+  "os"
+  "path/filepath"
+  "crypto/elliptic"
+  "crypto/ecdsa"
+  "crypto/x509"
+//  "crypto/x509/pkix"
+  "crypto/rand"
+  "encoding/pem"
+//  "code.google.com/p/go.crypto/ssh/terminal"
+//  "math/big"
+//  "time"
+)
+
+const (
+  RsaLowerLength = 2048
+  RsaUpperLength = 4096
+)
+
+var (
+  EcdsaLength = []int{224, 256, 384, 521}
+)
+
+type (
+  CreateFlags struct {
+    CryptType   string // rsa or ecdsa
+    CryptLength int    // the bit length
+    Output      string // a path or stream to output the private key to
+
+    output_stream io.WriteCloser // the actual stream to the output
+  }
+)
+
+func main() {
+  if len(os.Args) == 1 {
+    crash_with_help(1, "No module selected!")
+  }
+  switch os.Args[1] {
+  case "create-private": create_private_key()
+  case "create-cert-sign": create_sign_request()
+  case "help": print_modules()
+  case "info": info_on_file()
+  case "sign": sign_request()
+  }
+}
+
+// create a new private key
+func create_private_key() {
+  flags := parse_create_flags()
+
+  if flags.Output == "STDOUT" {
+    flags.output_stream = os.Stdout
+  } else {
+    var err error
+    flags.output_stream, err = os.OpenFile(flags.Output, os.O_WRONLY | os.O_CREATE | os.O_TRUNC, 0600)
+    if err != nil {
+      crash_with_help(2, fmt.Sprintf("Error when creating file %s: %s", flags.Output, err))
+    }
+    defer flags.output_stream.Close()
+  }
+
+  switch flags.CryptType {
+    case "rsa":   create_private_key_rsa(flags)
+    case "ecdsa": create_private_key_ecdsa(flags)
+    default: crash_with_help(2, fmt.Sprintf("%s not supported!", flags.CryptType))
+  }
+}
+
+// generate a rsa private key
+func create_private_key_rsa(flags CreateFlags) {
+
+}
+
+// generate a ecdsa private key 
+func create_private_key_ecdsa(flags CreateFlags) {
+  var curve elliptic.Curve
+  switch flags.CryptLength {
+    case 224: curve = elliptic.P224()
+    case 256: curve = elliptic.P256()
+    case 384: curve = elliptic.P384()
+    case 521: curve = elliptic.P521()
+    default: crash_with_help(2, "Unsupported crypt length!")
+  }
+
+  priv, err := ecdsa.GenerateKey(curve, rand.Reader)
+  if err != nil {
+    fmt.Println("Error: ", err)
+    os.Exit(3)
+  }
+  result, err := x509.MarshalECPrivateKey(priv)
+  if err != nil {
+    crash_with_help(2, fmt.Sprintf("Problems marshalling the private key: %s", err))
+  }
+  block := &pem.Block{Type: "ECDSA PRIVATE KEY", Bytes: result}
+  pem.Encode(flags.output_stream, block)
+}
+
+// parse the flags to create a private key
+func parse_create_flags() CreateFlags {
+  flags := CreateFlags{}
+  fs := flag.NewFlagSet("create-private", flag.ExitOnError)
+  fs.StringVar(&flags.CryptType, "type", "ecdsa", "which type to use to encrypt key (rsa, ecdsa)")
+  fs.IntVar(&flags.CryptLength, "length", 521, fmt.Sprintf(
+                      "%i - %i for rsa; %v for ecdsa", RsaLowerLength, RsaUpperLength, EcdsaLength,))
+  fs.StringVar(&flags.Output, "output", "STDOUT", "filename to store the private key")
+  fs.Parse(os.Args[2:])
+
+  return flags
+}
+
+// create a sign request with a private key
+func create_sign_request() {}
+// get information on file (private key, sign request, certificate, ...)
+func info_on_file() {}
+// sign a certificate request to create a new certificate
+func sign_request() {}
+
+// print the module help
+func print_modules() {
+  fmt.Printf(`Usage: %s command args
+where 'command' is one of:
+    create-private    create a new private key
+    create-cert-sign  create a new certificate sign request
+    help              show this help
+    info              get info on a file
+    sign              sign a certificate request
+`, filepath.Base(os.Args[0]))
+  fmt.Println()
+}
+
+func crash_with_help(code int, message string) {
+  fmt.Fprintln(os.Stderr, message)
+  print_modules()
+  os.Exit(code)
+}
+
+//  fmt.Println("Lets create a cert!")
+//  template := &x509.Certificate{
+//    SerialNumber:  big.NewInt(1),
+//    Subject: pkix.Name{
+//      Organization: []string{"Acme Co"},
+//    },
+//    NotBefore: time.Now(),
+//    NotAfter: time.Now().Add(365 * 24 * time.Hour),
+//    KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
+//    ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
+//    BasicConstraintsValid: true,
+//  }
+//  priv, err := ecdsa.GenerateKey(elliptic.P521(), rand.Reader)
+//  fmt.Println(priv.PublicKey, err)
+//  raw_string, err := x509.CreateCertificate(rand.Reader, template, template, &priv.PublicKey, priv)
+//  cert, err := x509.ParseCertificate(raw_string)
+//  fmt.Println(cert, err)
+//
+//  // read a password or so
+//  password, err := terminal.ReadPassword(0)
+//  fmt.Println(string(password), err)
+//}