feat(all): v1.0

pkg/lzkit/crypto/west_crypto.go

@@ -0,0 +1,150 @@
+package crypto
+
+import (
+	"bytes"
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/sha1"
+	"encoding/base64"
+)
+
+const (
+	KEY_SIZE = 16 // AES-128, 16 bytes
+)
+
+// Encrypt encrypts the given data using AES encryption in ECB mode with PKCS5 padding
+func WestDexEncrypt(data, secretKey string) (string, error) {
+	key := generateAESKey(KEY_SIZE*8, []byte(secretKey))
+	ciphertext, err := aesEncrypt([]byte(data), key)
+	if err != nil {
+		return "", err
+	}
+	return base64.StdEncoding.EncodeToString(ciphertext), nil
+}
+
+// Decrypt decrypts the given base64-encoded string using AES encryption in ECB mode with PKCS5 padding
+func WestDexDecrypt(encodedData, secretKey string) ([]byte, error) {
+	ciphertext, err := base64.StdEncoding.DecodeString(encodedData)
+	if err != nil {
+		return nil, err
+	}
+	key := generateAESKey(KEY_SIZE*8, []byte(secretKey))
+	plaintext, err := aesDecrypt(ciphertext, key)
+	if err != nil {
+		return nil, err
+	}
+	return plaintext, nil
+}
+
+// generateAESKey generates a key for AES encryption using a SHA-1 based PRNG
+func generateAESKey(length int, password []byte) []byte {
+	h := sha1.New()
+	h.Write(password)
+	state := h.Sum(nil)
+
+	keyBytes := make([]byte, 0, length/8)
+	for len(keyBytes) < length/8 {
+		h := sha1.New()
+		h.Write(state)
+		state = h.Sum(nil)
+		keyBytes = append(keyBytes, state...)
+	}
+
+	return keyBytes[:length/8]
+}
+
+// aesEncrypt encrypts plaintext using AES in ECB mode with PKCS5 padding
+func aesEncrypt(plaintext, key []byte) ([]byte, error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	paddedPlaintext := pkcs5Padding(plaintext, block.BlockSize())
+	ciphertext := make([]byte, len(paddedPlaintext))
+	mode := newECBEncrypter(block)
+	mode.CryptBlocks(ciphertext, paddedPlaintext)
+	return ciphertext, nil
+}
+
+// aesDecrypt decrypts ciphertext using AES in ECB mode with PKCS5 padding
+func aesDecrypt(ciphertext, key []byte) ([]byte, error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	plaintext := make([]byte, len(ciphertext))
+	mode := newECBDecrypter(block)
+	mode.CryptBlocks(plaintext, ciphertext)
+	return pkcs5Unpadding(plaintext), nil
+}
+
+// pkcs5Padding pads the input to a multiple of the block size using PKCS5 padding
+func pkcs5Padding(src []byte, blockSize int) []byte {
+	padding := blockSize - len(src)%blockSize
+	padtext := bytes.Repeat([]byte{byte(padding)}, padding)
+	return append(src, padtext...)
+}
+
+// pkcs5Unpadding removes PKCS5 padding from the input
+func pkcs5Unpadding(src []byte) []byte {
+	length := len(src)
+	unpadding := int(src[length-1])
+	return src[:(length - unpadding)]
+}
+
+// ECB mode encryption/decryption
+type ecb struct {
+	b         cipher.Block
+	blockSize int
+}
+
+func newECB(b cipher.Block) *ecb {
+	return &ecb{
+		b:         b,
+		blockSize: b.BlockSize(),
+	}
+}
+
+type ecbEncrypter ecb
+
+func newECBEncrypter(b cipher.Block) cipher.BlockMode {
+	return (*ecbEncrypter)(newECB(b))
+}
+
+func (x *ecbEncrypter) BlockSize() int { return x.blockSize }
+
+func (x *ecbEncrypter) CryptBlocks(dst, src []byte) {
+	if len(src)%x.blockSize != 0 {
+		panic("crypto/cipher: input not full blocks")
+	}
+	if len(dst) < len(src) {
+		panic("crypto/cipher: output smaller than input")
+	}
+	for len(src) > 0 {
+		x.b.Encrypt(dst, src[:x.blockSize])
+		src = src[x.blockSize:]
+		dst = dst[x.blockSize:]
+	}
+}
+
+type ecbDecrypter ecb
+
+func newECBDecrypter(b cipher.Block) cipher.BlockMode {
+	return (*ecbDecrypter)(newECB(b))
+}
+
+func (x *ecbDecrypter) BlockSize() int { return x.blockSize }
+
+func (x *ecbDecrypter) CryptBlocks(dst, src []byte) {
+	if len(src)%x.blockSize != 0 {
+		panic("crypto/cipher: input not full blocks")
+	}
+	if len(dst) < len(src) {
+		panic("crypto/cipher: output smaller than input")
+	}
+	for len(src) > 0 {
+		x.b.Decrypt(dst, src[:x.blockSize])
+		src = src[x.blockSize:]
+		dst = dst[x.blockSize:]
+	}
+}