refactor: disambiguate blowfish crypto helper names

internal/crypto/blowfish.go

@@ -9,31 +9,31 @@ import (
 )
 
 var (
-	iv        = []byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07}
-	secretKey = []byte("g4el58wc0zvf9na1")
+	blowfishIV        = []byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07}
+	blowfishSecretKey = []byte("g4el58wc0zvf9na1")
 )
 
-func GetKey(songID string) []byte {
+func GetBlowfishKey(songID string) []byte {
 	hash := md5.Sum([]byte(songID))
 	hashHex := hex.EncodeToString(hash[:])
 
-	key := make([]byte, len(secretKey))
-	copy(key, secretKey)
-	for i := 0; i < len(hash); i++ {
+	key := make([]byte, len(blowfishSecretKey))
+	copy(key, blowfishSecretKey)
+	for i := range len(hash) {
 		key[i] = key[i] ^ hashHex[i] ^ hashHex[i+16]
 	}
 
 	return key
 }
 
-func Decrypt(data, key []byte) ([]byte, error) {
+func DecryptBlowfish(data, key []byte) ([]byte, error) {
 	block, err := blowfish.NewCipher(key)
 	if err != nil {
 		return nil, err
 	}
 
 	decrypted := make([]byte, len(data))
-	cipher.NewCBCDecrypter(block, iv).CryptBlocks(decrypted, data)
+	cipher.NewCBCDecrypter(block, blowfishIV).CryptBlocks(decrypted, data)
 
 	return decrypted, nil
 }