updating refs, finished key gen buffer

sshkeys/crypt.go

@@ -0,0 +1,57 @@
+package sshkeys
+
+import (
+	`crypto/aes`
+	`crypto/cipher`
+	`errors`
+
+	// `golang.org/x/crypto/ssh/internal/bcrypt_pbkdf` Golang doesn't let you import "internal" libs. Fine. Lame language.
+	`github.com/dchest/bcrypt_pbkdf`
+)
+
+func (k *EncryptedSSHKeyV1) setCrypt() error {
+	// First we need the KDF (Key Derivation Function).
+	if err := k.setKDF(); err != nil {
+		return err
+	}
+	// And then we set the actual cipher (the thing that does the encrypting).
+	if err := k.setCipher(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (k *EncryptedSSHKeyV1) setCipher() error {
+	switch k.CipherName {
+	case CipherAes256Ctr:
+		if k.Crypt.Cipher, err = aes.NewCipher(k.Crypt.PrivateKey); err != nil {
+			return err
+		} else {
+			k.Crypt.Stream = cipher.NewCTR(k.Crypt.Cipher, k.Crypt.CryptSalt)
+			// Can then be used as k.Crypt.Stream.XORKeyStream(dst []byte, src []byte)
+		}
+	default:
+		return errors.New("could not find Cipher")
+	}
+	return nil
+}
+
+func (k *EncryptedSSHKeyV1) setKDF() error {
+	// Upstream only currently supports bcrypt_pbkdf ("bcrypt").
+	// This should always eval to true, but is here for future planning in case other KDF are implemented.
+	switch k.KDFName {
+	case KdfBcrypt:
+		if k.Crypt.CryptKey, err = bcrypt_pbkdf.Key(k.Passphrase,
+													k.KDFOpts.Salt,
+													int(k.KDFOpts.Rounds),
+													kdfKeyLen + len(k.KDFOpts.Salt),
+		); err != nil {
+			return err
+		} else {
+			k.Crypt.PrivateKey = k.Crypt.CryptKey[0:kdfSplit]
+			k.Crypt.CryptSalt = k.Crypt.CryptKey[kdfSplit:]
+		}
+	default:
+		return errors.New("could not find KDF")
+	}
+}