Added test for crypt (#1)

* Added test for crypt

* Added test for crypt

* Added test for crypt

* Added test for crypt

* Added test for crypt

crypt/crypt_test.go

@@ -0,0 +1,91 @@
+package crypt
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestLimitsKeySize(t *testing.T) {
+	_, _, err := GenerateKeyPair(512)
+	if err == nil {
+		t.Errorf("GenerateKeyPair returned no error")
+	}
+
+	_, _, err = GenerateKeyPair(16385)
+	if err == nil {
+		t.Errorf("GenerateKeyPair returned no error")
+	}
+
+	_, _, err = GenerateKeyPair(0)
+	if err != nil {
+		t.Errorf("GenerateKeyPair returned an error")
+	}
+}
+
+func TestEncryption(t *testing.T) {
+	data := []byte("hello world")
+
+	keyPem, pubPem, err := GenerateKeyPair(2048)
+
+	if err != nil {
+		t.Error(err)
+	}
+
+	ef := EncryptedFile{
+		plainText:  data,
+		PublicPem:  pubPem,
+		privatePem: keyPem,
+	}
+
+	err = ef.ParsePublicPem()
+	if err != nil {
+		t.Error(err)
+	}
+
+	err = ef.ParsePrivatePem()
+	if err != nil {
+		t.Error(err)
+	}
+
+	err = ef.GenerateSymmetricKey()
+	if err != nil {
+		t.Error(err)
+	}
+
+	err = ef.EncryptFile()
+	if err != nil {
+		t.Error(err)
+	}
+
+	if len(ef.ciphertext) == 0 {
+		t.Error("ciphertext is empty")
+	}
+
+	if len(ef.nonce) == 0 {
+		t.Error("nonce is empty")
+	}
+
+	if bytes.Equal(ef.plainText, ef.ciphertext) {
+		t.Error("ciphertext and plaintext are the same")
+	}
+
+	dc := EncryptedFile{
+		ciphertext: ef.ciphertext,
+		privatePem: keyPem,
+	}
+
+	err = dc.ParsePrivatePem()
+	if err != nil {
+		t.Error(err)
+	}
+
+	err = dc.unpackFileAndDecrypt(ef.packFile())
+	if err != nil {
+		t.Error(err)
+	}
+
+	if !bytes.Equal(ef.plainText, dc.plainText) {
+		t.Error("plaintext and plaintext are different")
+	}
+
+}

crypt/pem.go

@@ -0,0 +1,47 @@
+package crypt
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
+)
+
+func GenerateKeyPair(bitSize int) ([]byte, []byte, error) {
+	if bitSize == 0 {
+		bitSize = 4096
+	}
+
+	if bitSize < 2048 {
+		return nil, nil, fmt.Errorf("key to weak. size must be greater than 2048")
+	}
+
+	if bitSize > 16384 {
+		return nil, nil, fmt.Errorf("key to large. size must be less than 16384")
+	}
+
+	key, err := rsa.GenerateKey(rand.Reader, bitSize)
+
+	if err != nil {
+		return nil, nil, err
+	}
+
+	keyPEM := pem.EncodeToMemory(
+		&pem.Block{
+			Type:  "RSA PRIVATE KEY",
+			Bytes: x509.MarshalPKCS1PrivateKey(key),
+		},
+	)
+
+	pub := key.Public()
+
+	pubPEM := pem.EncodeToMemory(
+		&pem.Block{
+			Type:  "RSA PUBLIC KEY",
+			Bytes: x509.MarshalPKCS1PublicKey(pub.(*rsa.PublicKey)),
+		},
+	)
+
+	return keyPEM, pubPEM, nil
+}