init: dec-music 项目初始化

internal/crypto/crypto.go

@@ -0,0 +1,33 @@
+package crypto
+
+import "crypto/aes"
+
+// PKCS7UnPadding removes PKCS#7 padding.
+func PKCS7UnPadding(encrypt []byte) []byte {
+	length := len(encrypt)
+	if length == 0 {
+		return encrypt
+	}
+	unPadding := int(encrypt[length-1])
+	if unPadding <= 0 || unPadding > length {
+		return encrypt
+	}
+	return encrypt[:length-unPadding]
+}
+
+// DecryptAES128ECB decrypts data with AES-128 ECB (block size 16).
+func DecryptAES128ECB(data, key []byte) []byte {
+	cipher, err := aes.NewCipher(key)
+	if err != nil {
+		return nil
+	}
+	decrypted := make([]byte, len(data))
+	size := aes.BlockSize
+	for bs, be := 0, size; bs < len(data); bs, be = bs+size, be+size {
+		if be > len(data) {
+			break
+		}
+		cipher.Decrypt(decrypted[bs:be], data[bs:be])
+	}
+	return decrypted
+}