refactor: add comments and format code style

internal/decrypter/decrypter.go

@@ -44,7 +44,7 @@ func NewASN1PBE(b []byte) (pbe ASN1PBE, err error) {
 }
 
 // nssPBE Struct
-// SEQUENCE (2 elem)
+//
 //	SEQUENCE (2 elem)
 //		OBJECT IDENTIFIER
 //		SEQUENCE (2 elem)
@@ -62,10 +62,6 @@ type nssPBE struct {
 	Encrypted []byte
 }
 
-func (n nssPBE) entrySalt() []byte {
-	return n.AlgoAttr.SaltAttr.EntrySalt
-}
-
 func (n nssPBE) Decrypt(globalSalt, masterPwd []byte) (key []byte, err error) {
 	glmp := append(globalSalt, masterPwd...)
 	hp := sha1.Sum(glmp)
@@ -82,11 +78,19 @@ func (n nssPBE) Decrypt(globalSalt, masterPwd []byte) (key []byte, err error) {
 	k2.Write(tkPlus)
 	k := append(k1.Sum(nil), k2.Sum(nil)...)
 	iv := k[len(k)-8:]
-	return des3Decrypt(k[:24], iv, n.Encrypted)
+	return des3Decrypt(k[:24], iv, n.encrypted())
+}
+
+func (n nssPBE) entrySalt() []byte {
+	return n.AlgoAttr.SaltAttr.EntrySalt
+}
+
+func (n nssPBE) encrypted() []byte {
+	return n.Encrypted
 }
 
 // MetaPBE Struct
-// SEQUENCE (2 elem)
+//
 //	SEQUENCE (2 elem)
 //		OBJECT IDENTIFIER
 //	    SEQUENCE (2 elem)
@@ -135,8 +139,8 @@ type slatAttr struct {
 func (m metaPBE) Decrypt(globalSalt, masterPwd []byte) (key2 []byte, err error) {
 	k := sha1.Sum(globalSalt)
 	key := pbkdf2.Key(k[:], m.entrySalt(), m.iterationCount(), m.keySize(), sha256.New)
-	iv := append([]byte{4, 14}, m.AlgoAttr.Data.IVData.IV...)
-	return aes128CBCDecrypt(key, iv, m.Encrypted)
+	iv := append([]byte{4, 14}, m.iv()...)
+	return aes128CBCDecrypt(key, iv, m.encrypted())
 }
 
 func (m metaPBE) entrySalt() []byte {
@@ -151,8 +155,16 @@ func (m metaPBE) keySize() int {
 	return m.AlgoAttr.Data.Data.SlatAttr.KeySize
 }
 
+func (m metaPBE) iv() []byte {
+	return m.AlgoAttr.Data.IVData.IV
+}
+
+func (m metaPBE) encrypted() []byte {
+	return m.Encrypted
+}
+
 // loginPBE Struct
-// SEQUENCE (3 elem)
+//
 //	OCTET STRING (16 byte)
 //	SEQUENCE (2 elem)
 //			OBJECT IDENTIFIER
@@ -168,7 +180,14 @@ type loginPBE struct {
 }
 
 func (l loginPBE) Decrypt(globalSalt, masterPwd []byte) (key []byte, err error) {
-	return des3Decrypt(globalSalt, l.Data.IV, l.Encrypted)
+	return des3Decrypt(globalSalt, l.iv(), l.encrypted())
+}
+
+func (l loginPBE) iv() []byte {
+	return l.Data.IV
+}
+func (l loginPBE) encrypted() []byte {
+	return l.Encrypted
 }
 
 func aes128CBCDecrypt(key, iv, encryptPass []byte) ([]byte, error) {
@@ -197,7 +216,7 @@ func pkcs5UnPadding(src []byte, blockSize int) []byte {
 	return src[:n-paddingNum]
 }
 
-// des3Decrypt use for decrypter firefox PBE
+// des3Decrypt use for decrypt firefox PBE
 func des3Decrypt(key, iv []byte, src []byte) ([]byte, error) {
 	block, err := des.NewTripleDESCipher(key)
 	if err != nil {
@@ -213,10 +232,9 @@ func paddingZero(s []byte, l int) []byte {
 	h := l - len(s)
 	if h <= 0 {
 		return s
-	} else {
+	}
 	for i := len(s); i < l; i++ {
 		s = append(s, 0)
 	}
 	return s
-	}
 }

internal/decrypter/decrypter_darwin.go

@@ -1,17 +1,17 @@
 package decrypter
 
 func Chromium(key, encryptPass []byte) ([]byte, error) {
-	if len(encryptPass) > 3 {
+	if len(encryptPass) <= 3 {
+		return nil, errPasswordIsEmpty
+	}
 	if len(key) == 0 {
 		return nil, errSecurityKeyIsEmpty
 	}
-		chromeIV := []byte{32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32}
-		return aes128CBCDecrypt(key, chromeIV, encryptPass[3:])
-	} else {
-		return nil, errDecryptFailed
-	}
+
+	iv := []byte{32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32}
+	return aes128CBCDecrypt(key, iv, encryptPass[3:])
 }
 
-func DPApi(data []byte) ([]byte, error) {
+func DPAPI(data []byte) ([]byte, error) {
 	return nil, nil
 }

internal/decrypter/decrypter_linux.go

@@ -1,17 +1,17 @@
 package decrypter
 
 func Chromium(key, encryptPass []byte) ([]byte, error) {
-	chromeIV := []byte{32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32}
-	if len(encryptPass) > 3 {
+	if len(encryptPass) < 3 {
+		return nil, errPasswordIsEmpty
+	}
 	if len(key) == 0 {
 		return nil, errSecurityKeyIsEmpty
 	}
+
+	chromeIV := []byte{32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32}
 	return aes128CBCDecrypt(key, chromeIV, encryptPass[3:])
-	} else {
-		return nil, errDecryptFailed
-	}
 }
 
-func DPApi(data []byte) ([]byte, error) {
+func DPAPI(data []byte) ([]byte, error) {
 	return nil, nil
 }

internal/decrypter/decrypter_windows.go

@@ -8,25 +8,29 @@ import (
 )
 
 func Chromium(key, encryptPass []byte) ([]byte, error) {
-	if len(encryptPass) > 15 {
-		// remove Prefix 'v10'
-		return aesGCMDecrypt(encryptPass[15:], key, encryptPass[3:15])
-	} else {
+	if len(encryptPass) < 3 {
 		return nil, errPasswordIsEmpty
 	}
+	if len(key) == 0 {
+		return nil, errSecurityKeyIsEmpty
+	}
+
+	return aesGCMDecrypt(encryptPass[15:], key, encryptPass[3:15])
 }
 
 func ChromiumForYandex(key, encryptPass []byte) ([]byte, error) {
-	if len(encryptPass) > 15 {
+	if len(encryptPass) < 3 {
+		return nil, errPasswordIsEmpty
+	}
+	if len(key) == 0 {
+		return nil, errSecurityKeyIsEmpty
+	}
 	// remove Prefix 'v10'
 	// gcmBlockSize         = 16
 	// gcmTagSize           = 16
 	// gcmMinimumTagSize    = 12 // NIST SP 800-38D recommends tags with 12 or more bytes.
 	// gcmStandardNonceSize = 12
 	return aesGCMDecrypt(encryptPass[12:], key, encryptPass[0:12])
-	} else {
-		return nil, errPasswordIsEmpty
-	}
 }
 
 // chromium > 80 https://source.chromium.org/chromium/chromium/src/+/master:components/os_crypt/os_crypt_win.cc
@@ -67,9 +71,12 @@ func (b *dataBlob) ToByteArray() []byte {
 	return d
 }
 
-// DPApi
+// DPAPI (Data Protection Application Programming Interface)
+// is a simple cryptographic application programming interface
+// available as a built-in component in Windows 2000 and
+// later versions of Microsoft Windows operating systems
 // chrome < 80 https://chromium.googlesource.com/chromium/src/+/76f496a7235c3432983421402951d73905c8be96/components/os_crypt/os_crypt_win.cc#82
-func DPApi(data []byte) ([]byte, error) {
+func DPAPI(data []byte) ([]byte, error) {
 	dllCrypt := syscall.NewLazyDLL("Crypt32.dll")
 	dllKernel := syscall.NewLazyDLL("Kernel32.dll")
 	procDecryptData := dllCrypt.NewProc("CryptUnprotectData")