init

utils/aes.go

@@ -0,0 +1,94 @@
+package utils
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"errors"
+)
+
+// NewAESPresharedKey typ AES-128, AES-192, or AES-256.
+func NewAESPresharedKey(typ string) ([]byte, error) {
+	sz := 0
+	switch typ {
+	case "AES-128":
+		sz = 16
+	case "AES-192":
+		sz = 24
+	case "AES-256":
+		sz = 32
+	}
+	if sz <= 0 {
+		return nil, aes.KeySizeError(sz)
+	}
+	k := make([]byte, sz)
+	_, err := rand.Read(k)
+	if err != nil {
+		return nil, err
+	}
+	return k, nil
+}
+
+// EncryptAES ...
+func EncryptAES(aescipher cipher.Block, data []byte) []byte {
+	blksz := aescipher.BlockSize()
+	total := len(data)
+	n := total / blksz
+	if total%blksz > 0 {
+		n++
+	}
+	encdat := make([]byte, blksz*n)
+	copy(encdat, data)
+	for i := 0; i < n; i++ {
+		a := i * blksz
+		b := (i + 1) * blksz
+		aescipher.Encrypt(encdat[a:b], encdat[a:b])
+	}
+	return encdat
+}
+
+// EncryptAESInplace ...
+func EncryptAESInplace(aescipher cipher.Block, data []byte) error {
+	blksz := aescipher.BlockSize()
+	total := len(data)
+	n := total / blksz
+	if total%blksz > 0 {
+		n++
+	}
+	if len(data) < blksz*n {
+		return errors.New("data is too short")
+	}
+	for i := 0; i < n; i++ {
+		a := i * blksz
+		b := (i + 1) * blksz
+		aescipher.Encrypt(data[a:b], data[a:b])
+	}
+	return nil
+}
+
+// DecryptAES ...
+func DecryptAES(aescipher cipher.Block, data []byte) []byte {
+	blksz := aescipher.BlockSize()
+	total := len(data)
+	n := total / blksz
+	decdat := make([]byte, blksz*n)
+	for i := 0; i < n; i++ {
+		a := i * blksz
+		b := (i + 1) * blksz
+		aescipher.Decrypt(decdat[a:b], data[a:b])
+	}
+	return decdat
+}
+
+// DecryptAESInplace ...
+func DecryptAESInplace(aescipher cipher.Block, data []byte) error {
+	blksz := aescipher.BlockSize()
+	total := len(data)
+	n := total / blksz
+	for i := 0; i < n; i++ {
+		a := i * blksz
+		b := (i + 1) * blksz
+		aescipher.Decrypt(data[a:b], data[a:b])
+	}
+	return nil
+}