Initial QSfera import

Server/services/collaboration/pkg/middleware/crypto.go

@@ -0,0 +1,83 @@
+package middleware
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"io"
+)
+
+// keyPadding will add the required zero padding to the provided key.
+// The resulting key will have a length of either 16, 24 or 32 bytes.
+// If the key has more than 32 bytes, only the first 32 bytes will be returned.
+func keyPadding(key []byte) []byte {
+	switch length := len(key); {
+	case length < 16:
+		return append(key, make([]byte, 16-length)...)
+	case length == 16:
+		return key
+	case length < 24:
+		return append(key, make([]byte, 24-length)...)
+	case length == 24:
+		return key
+	case length < 32:
+		return append(key, make([]byte, 32-length)...)
+	case length == 32:
+		return key
+	case length > 32:
+		return key[:32]
+	}
+	return []byte{}
+}
+
+// EncryptAES encrypts the provided plainText using the provided key.
+// AES CFB will be used as cryptographic method.
+// Use DecryptAES to decrypt the resulting string
+func EncryptAES(key []byte, plainText string) (string, error) {
+	src := []byte(plainText)
+
+	block, err := aes.NewCipher(keyPadding(key))
+	if err != nil {
+		return "", err
+	}
+
+	cipherText := make([]byte, aes.BlockSize+len(src))
+	iv := cipherText[:aes.BlockSize]
+	if _, err = io.ReadFull(rand.Reader, iv); err != nil {
+		return "", err
+	}
+
+	stream := cipher.NewCFBEncrypter(block, iv)
+	stream.XORKeyStream(cipherText[aes.BlockSize:], src)
+
+	return base64.URLEncoding.EncodeToString(cipherText), nil
+}
+
+// DecryptAES decrypts the provided string using the provided key.
+// The provided string must have been encrypted with AES CFB.
+// This method will decrypt the result from the EncryptAES method
+func DecryptAES(key []byte, securemess string) (string, error) {
+	cipherText, err := base64.URLEncoding.DecodeString(securemess)
+	if err != nil {
+		return "", err
+	}
+
+	block, err := aes.NewCipher(keyPadding(key))
+	if err != nil {
+		return "", err
+	}
+
+	if len(cipherText) < aes.BlockSize {
+		return "", errors.New("ciphertext block size is too short")
+	}
+
+	iv := cipherText[:aes.BlockSize]
+	cipherText = cipherText[aes.BlockSize:]
+
+	stream := cipher.NewCFBDecrypter(block, iv)
+	stream.XORKeyStream(cipherText, cipherText)
+
+	return string(cipherText), nil
+}