forked from 9elements/converged-security-suite
/
keygen.go
237 lines (213 loc) · 5.4 KB
/
keygen.go
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package cbnt
import (
"crypto"
"crypto/aes"
"crypto/cipher"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"encoding/pem"
"fmt"
"io/ioutil"
"os"
"strings"
)
const (
//Supported RSA bit length of Intel TXT/CBnT technology
rsaLen2048 = int(2048)
rsaLen3072 = int(3072)
)
// GenRSAKey takes the required keylength, two boolean to decide for KM and BPM key and a path
// to create a RSA key pair and writes its public and private keys to files.
func GenRSAKey(len int, password string, kmPubFile, kmPrivFile, bpmPubFile, bpmPrivFile *os.File) error {
if len == rsaLen2048 || len == rsaLen3072 {
key, err := rsa.GenerateKey(rand.Reader, len)
if err != nil {
return err
}
if err := writePrivKeyToFile(key, kmPrivFile, password); err != nil {
return err
}
if err := writePubKeyToFile(key.Public(), kmPubFile); err != nil {
return err
}
key, err = rsa.GenerateKey(rand.Reader, len)
if err != nil {
return err
}
if err := writePrivKeyToFile(key, bpmPrivFile, password); err != nil {
return err
}
if err := writePubKeyToFile(key.Public(), bpmPubFile); err != nil {
return err
}
return nil
}
return fmt.Errorf("RSA key length must be 2048 or 3084 Bits, but length is: %d", len)
}
// GenECCKey takes the required curve, two boolean to decide for KM and BPM key and a path
// to create a ECDSA key pair and writes its public and private keys to files.
func GenECCKey(curve int, password string, kmPubFile, kmPrivFile, bpmPubFile, bpmPrivFile *os.File) error {
var ellCurve elliptic.Curve
switch curve {
case 224:
ellCurve = elliptic.P224()
case 256:
ellCurve = elliptic.P256()
default:
return fmt.Errorf("selected ECC algorithm not supported")
}
key, err := ecdsa.GenerateKey(ellCurve, rand.Reader)
if err != nil {
return err
}
if err := writePrivKeyToFile(key, kmPrivFile, password); err != nil {
return err
}
if err := writePubKeyToFile(key.Public(), kmPubFile); err != nil {
return err
}
key, err = ecdsa.GenerateKey(ellCurve, rand.Reader)
if err != nil {
return err
}
if err := writePrivKeyToFile(key, bpmPrivFile, password); err != nil {
return err
}
if err := writePubKeyToFile(key.Public(), bpmPubFile); err != nil {
return err
}
return nil
}
func writePrivKeyToFile(k crypto.PrivateKey, f *os.File, password string) error {
var key *[]byte
b, err := x509.MarshalPKCS8PrivateKey(k)
if err != nil {
return fmt.Errorf("unable to marshal the private key: %w", err)
}
bpemBlock := &pem.Block{
Bytes: b,
}
bpem := pem.EncodeToMemory(bpemBlock)
if password != "" {
encKey, err := encryptPrivFile(&bpem, password)
if err != nil {
return err
}
key = encKey
} else {
key = &bpem
}
_, err = f.Write(*key)
if err != nil {
return err
}
return nil
}
func writePubKeyToFile(k crypto.PublicKey, f *os.File) error {
b, err := x509.MarshalPKIXPublicKey(k)
if err != nil {
return err
}
bpemBlock := &pem.Block{
Bytes: b,
}
bpem := pem.EncodeToMemory(bpemBlock)
_, err = f.Write(bpem)
if err != nil {
return err
}
return nil
}
func encryptPrivFile(data *[]byte, password string) (*[]byte, error) {
// Hash key to select aes-256 -> using SHA256
hash := crypto.SHA256.New()
if _, err := hash.Write([]byte(password)); err != nil {
return nil, fmt.Errorf("unable to hash: %w", err)
}
hashPW := hash.Sum(nil)
bc, err := aes.NewCipher(hashPW)
if err != nil {
return nil, err
}
gcm, err := cipher.NewGCM(bc)
if err != nil {
return nil, err
}
nonce := make([]byte, gcm.NonceSize())
if _, err := rand.Read(nonce); err != nil {
return nil, err
}
ct := gcm.Seal(nonce, nonce, *data, nil)
return &ct, nil
}
// DecryptPrivKey takes the encrypted Key as byte slice and the password to decrypt the private key and returns it with it's type.
func DecryptPrivKey(data []byte, password string) (crypto.PrivateKey, error) {
var plain []byte
if password != "" {
// Set up the crypto stuff
hash := crypto.SHA256.New()
if _, err := hash.Write([]byte(password)); err != nil {
return nil, fmt.Errorf("unable to hash: %w", err)
}
hashPW := hash.Sum(nil)
aes, err := aes.NewCipher(hashPW)
if err != nil {
return nil, err
}
aesGCM, err := cipher.NewGCM(aes)
if err != nil {
return nil, err
}
nonceSize := aesGCM.NonceSize()
nonce, ciphertext := data[:nonceSize], data[nonceSize:]
plain, err = aesGCM.Open(nil, nonce, ciphertext, nil)
if err != nil {
return nil, err
}
} else {
plain = data
}
key, err := parsePrivateKey(plain)
if err != nil {
return nil, err
}
if err != nil {
return nil, err
}
return key, nil
}
// ReadPubKey ready a pem encoded RSA/ECC public key file
func ReadPubKey(path string) (crypto.PublicKey, error) {
raw, err := ioutil.ReadFile(path)
if err != nil {
return nil, err
}
for {
block, rest := pem.Decode(raw)
if block == nil {
break
}
if !strings.Contains(block.Type, "CERTIFICATE") {
if strings.Contains(block.Type, "RSA") {
key, err := x509.ParsePKCS1PublicKey(block.Bytes)
if err != nil {
return nil, fmt.Errorf("parsing error in x509.ParsePKCS1PublicKey: %v", err)
}
return key, nil
}
key, err := x509.ParsePKIXPublicKey(block.Bytes)
if err == nil {
if key, ok := key.(crypto.PublicKey); ok {
return key, nil
}
return nil, fmt.Errorf("found unknown public key type (%T) in PKIX wrapping", key)
}
return nil, err
}
raw = rest
}
return nil, fmt.Errorf("failed to parse public key")
}