[VOL-4291] Rw-core updates for gRPC migration
Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/github.com/jcmturner/aescts/v2/aescts.go b/vendor/github.com/jcmturner/aescts/v2/aescts.go
new file mode 100644
index 0000000..fee3b43
--- /dev/null
+++ b/vendor/github.com/jcmturner/aescts/v2/aescts.go
@@ -0,0 +1,186 @@
+// Package aescts provides AES CBC CipherText Stealing encryption and decryption methods
+package aescts
+
+import (
+ "crypto/aes"
+ "crypto/cipher"
+ "errors"
+ "fmt"
+)
+
+// Encrypt the message with the key and the initial vector.
+// Returns: next iv, ciphertext bytes, error
+func Encrypt(key, iv, plaintext []byte) ([]byte, []byte, error) {
+ l := len(plaintext)
+
+ block, err := aes.NewCipher(key)
+ if err != nil {
+ return []byte{}, []byte{}, fmt.Errorf("error creating cipher: %v", err)
+ }
+ mode := cipher.NewCBCEncrypter(block, iv)
+
+ m := make([]byte, len(plaintext))
+ copy(m, plaintext)
+
+ /*For consistency, ciphertext stealing is always used for the last two
+ blocks of the data to be encrypted, as in [RC5]. If the data length
+ is a multiple of the block size, this is equivalent to plain CBC mode
+ with the last two ciphertext blocks swapped.*/
+ /*The initial vector carried out from one encryption for use in a
+ subsequent encryption is the next-to-last block of the encryption
+ output; this is the encrypted form of the last plaintext block.*/
+ if l <= aes.BlockSize {
+ m, _ = zeroPad(m, aes.BlockSize)
+ mode.CryptBlocks(m, m)
+ return m, m, nil
+ }
+ if l%aes.BlockSize == 0 {
+ mode.CryptBlocks(m, m)
+ iv = m[len(m)-aes.BlockSize:]
+ rb, _ := swapLastTwoBlocks(m, aes.BlockSize)
+ return iv, rb, nil
+ }
+ m, _ = zeroPad(m, aes.BlockSize)
+ rb, pb, lb, err := tailBlocks(m, aes.BlockSize)
+ if err != nil {
+ return []byte{}, []byte{}, fmt.Errorf("error tailing blocks: %v", err)
+ }
+ var ct []byte
+ if rb != nil {
+ // Encrpt all but the lats 2 blocks and update the rolling iv
+ mode.CryptBlocks(rb, rb)
+ iv = rb[len(rb)-aes.BlockSize:]
+ mode = cipher.NewCBCEncrypter(block, iv)
+ ct = append(ct, rb...)
+ }
+ mode.CryptBlocks(pb, pb)
+ mode = cipher.NewCBCEncrypter(block, pb)
+ mode.CryptBlocks(lb, lb)
+ // Cipher Text Stealing (CTS) - Ref: https://en.wikipedia.org/wiki/Ciphertext_stealing#CBC_ciphertext_stealing
+ // Swap the last two cipher blocks
+ // Truncate the ciphertext to the length of the original plaintext
+ ct = append(ct, lb...)
+ ct = append(ct, pb...)
+ return lb, ct[:l], nil
+}
+
+// Decrypt the ciphertext with the key and the initial vector.
+func Decrypt(key, iv, ciphertext []byte) ([]byte, error) {
+ // Copy the cipher text as golang slices even when passed by value to this method can result in the backing arrays of the calling code value being updated.
+ ct := make([]byte, len(ciphertext))
+ copy(ct, ciphertext)
+ if len(ct) < aes.BlockSize {
+ return []byte{}, fmt.Errorf("ciphertext is not large enough. It is less that one block size. Blocksize:%v; Ciphertext:%v", aes.BlockSize, len(ct))
+ }
+ // Configure the CBC
+ block, err := aes.NewCipher(key)
+ if err != nil {
+ return nil, fmt.Errorf("error creating cipher: %v", err)
+ }
+ var mode cipher.BlockMode
+
+ //If ciphertext is multiple of blocksize we just need to swap back the last two blocks and then do CBC
+ //If the ciphertext is just one block we can't swap so we just decrypt
+ if len(ct)%aes.BlockSize == 0 {
+ if len(ct) > aes.BlockSize {
+ ct, _ = swapLastTwoBlocks(ct, aes.BlockSize)
+ }
+ mode = cipher.NewCBCDecrypter(block, iv)
+ message := make([]byte, len(ct))
+ mode.CryptBlocks(message, ct)
+ return message[:len(ct)], nil
+ }
+
+ // Cipher Text Stealing (CTS) using CBC interface. Ref: https://en.wikipedia.org/wiki/Ciphertext_stealing#CBC_ciphertext_stealing
+ // Get ciphertext of the 2nd to last (penultimate) block (cpb), the last block (clb) and the rest (crb)
+ crb, cpb, clb, _ := tailBlocks(ct, aes.BlockSize)
+ v := make([]byte, len(iv), len(iv))
+ copy(v, iv)
+ var message []byte
+ if crb != nil {
+ //If there is more than just the last and the penultimate block we decrypt it and the last bloc of this becomes the iv for later
+ rb := make([]byte, len(crb))
+ mode = cipher.NewCBCDecrypter(block, v)
+ v = crb[len(crb)-aes.BlockSize:]
+ mode.CryptBlocks(rb, crb)
+ message = append(message, rb...)
+ }
+
+ // We need to modify the cipher text
+ // Decryt the 2nd to last (penultimate) block with a the original iv
+ pb := make([]byte, aes.BlockSize)
+ mode = cipher.NewCBCDecrypter(block, iv)
+ mode.CryptBlocks(pb, cpb)
+ // number of byte needed to pad
+ npb := aes.BlockSize - len(ct)%aes.BlockSize
+ //pad last block using the number of bytes needed from the tail of the plaintext 2nd to last (penultimate) block
+ clb = append(clb, pb[len(pb)-npb:]...)
+
+ // Now decrypt the last block in the penultimate position (iv will be from the crb, if the is no crb it's zeros)
+ // iv for the penultimate block decrypted in the last position becomes the modified last block
+ lb := make([]byte, aes.BlockSize)
+ mode = cipher.NewCBCDecrypter(block, v)
+ v = clb
+ mode.CryptBlocks(lb, clb)
+ message = append(message, lb...)
+
+ // Now decrypt the penultimate block in the last position (iv will be from the modified last block)
+ mode = cipher.NewCBCDecrypter(block, v)
+ mode.CryptBlocks(cpb, cpb)
+ message = append(message, cpb...)
+
+ // Truncate to the size of the original cipher text
+ return message[:len(ct)], nil
+}
+
+func tailBlocks(b []byte, c int) ([]byte, []byte, []byte, error) {
+ if len(b) <= c {
+ return []byte{}, []byte{}, []byte{}, errors.New("bytes slice is not larger than one block so cannot tail")
+ }
+ // Get size of last block
+ var lbs int
+ if l := len(b) % aes.BlockSize; l == 0 {
+ lbs = aes.BlockSize
+ } else {
+ lbs = l
+ }
+ // Get last block
+ lb := b[len(b)-lbs:]
+ // Get 2nd to last (penultimate) block
+ pb := b[len(b)-lbs-c : len(b)-lbs]
+ if len(b) > 2*c {
+ rb := b[:len(b)-lbs-c]
+ return rb, pb, lb, nil
+ }
+ return nil, pb, lb, nil
+}
+
+func swapLastTwoBlocks(b []byte, c int) ([]byte, error) {
+ rb, pb, lb, err := tailBlocks(b, c)
+ if err != nil {
+ return nil, err
+ }
+ var out []byte
+ if rb != nil {
+ out = append(out, rb...)
+ }
+ out = append(out, lb...)
+ out = append(out, pb...)
+ return out, nil
+}
+
+// zeroPad pads bytes with zeros to nearest multiple of message size m.
+func zeroPad(b []byte, m int) ([]byte, error) {
+ if m <= 0 {
+ return nil, errors.New("invalid message block size when padding")
+ }
+ if b == nil || len(b) == 0 {
+ return nil, errors.New("data not valid to pad: Zero size")
+ }
+ if l := len(b) % m; l != 0 {
+ n := m - l
+ z := make([]byte, n)
+ b = append(b, z...)
+ }
+ return b, nil
+}