init: add rsa & aes

aes.go

@@ -0,0 +1,77 @@
+package tienyik
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"errors"
+)
+
+const (
+	ETPYE_AES_CBC = "2"
+)
+
+type TYAES [32]byte
+
+func NewTYAES(rawKey []byte) (tya TYAES) {
+	if len(rawKey) != 32 {
+		panic("len(key) must == 32")
+	}
+	copy(tya[:], rawKey)
+	return
+}
+
+func pkcs7Padding(data []byte, blockSize int) []byte {
+	padding := blockSize - len(data)%blockSize
+	padtext := make([]byte, padding)
+	for i := range padtext {
+		padtext[i] = byte(padding)
+	}
+	return append(data, padtext...)
+}
+
+func pkcs7Unpadding(data []byte) []byte {
+	if len(data) == 0 {
+		return data
+	}
+	padding := int(data[len(data)-1])
+	if padding > len(data) || padding == 0 {
+		return data
+	}
+	return data[:len(data)-padding]
+}
+
+func (tya TYAES) Encrypt(b []byte) []byte {
+	blk, err := aes.NewCipher(tya[:])
+	if err != nil {
+		panic(err)
+	}
+
+	paddedData := pkcs7Padding(b, aes.BlockSize)
+
+	mode := cipher.NewCBCEncrypter(blk, make([]byte, aes.BlockSize))
+	ciphertext := make([]byte, len(paddedData))
+	mode.CryptBlocks(ciphertext, paddedData)
+
+	return ciphertext
+}
+
+func (tya TYAES) Decrypt(b []byte) ([]byte, error) {
+	blk, err := aes.NewCipher(tya[:])
+	if err != nil {
+		return nil, err
+	}
+
+	if len(b) < aes.BlockSize {
+		return nil, errors.New("ciphertext too short")
+	}
+
+	if len(b)%aes.BlockSize != 0 {
+		return nil, errors.New("invalid ciphertext length")
+	}
+
+	mode := cipher.NewCBCDecrypter(blk, make([]byte, aes.BlockSize))
+	plaintext := make([]byte, len(b))
+	mode.CryptBlocks(plaintext, b)
+
+	return pkcs7Unpadding(plaintext), nil
+}