我想解密以前使用OpenSSL命令行工具加密的ruby 2.1脚本中的文本文件：
openssl enc -aes-256-cbc -a -salt -in my_file
openssl enc -aes-256-cbc -a -salt -in my_file
如命令中所示,该文件是AES-256-CBC加密,盐渍和base64编码.
密码是已知的,但不是IV和密钥,这是从ruby documentation获取的遵循此代码段所必需的：
decipher = OpenSSL::Cipher::AES.new 256,:CBC decipher.decrypt decipher.key = key decipher.iv = iv plain = decipher.update(encrypted_text) + decipher.final
在试图找到答案的同时,我发现了gem AESCrypt gem,它可以简化en-and decrypting,但目前发布的版本与ruby 2.1不兼容.
看着它的源代码,我发现密钥是retrieved by digesting the password和IV is just left as nil.
所以我尝试了以下运行：
encoded_and_encrypted_text = File.read my_file_path encrypted_text = Base64.decode64 encoded_and_encrypted_text.to_s.strip decipher = OpenSSL::Cipher::AES.new 256,:CBC decipher.decrypt decipher.key = OpenSSL::Digest::SHA256.new(my_password).digest plain_text = decipher.update(encrypted_text) + decipher.final
但这会导致OpenSSL :: Cipher :: CipherError：解密错误.
我是否需要以某种方式专门处理文件被腌制？我在OpenSSL documentation for the enc function中读到,如果在加密文件时未指定IV,则从密码生成.我需要以某种方式手动重建IV吗？
任何建议将受到高度赞赏:)
解决方法
OpenSSL使用自定义标头和密钥派生例程.
Security.SE has a good description of the header和
docs for
EVP_BytesToKey描述了密钥推导.
我们可以修改你的代码,使用这个奇怪的,有点破坏的密钥派生如下：
encoded_and_encrypted_text = File.read my_file_path encrypted_text = Base64.decode64 encoded_and_encrypted_text.to_s.strip header = encrypted_text[0,8] salt = encrypted_text[8,8] payload = encrypted_text[16..-1] decipher = OpenSSL::Cipher::AES.new 256,:CBC decipher.decrypt D_1 = OpenSSL::Digest::MD5.new(my_password + salt).digest D_2 = OpenSSL::Digest::MD5.new(D_1 + my_password + salt).digest D_3 = OpenSSL::Digest::MD5.new(D_2 + my_password + salt).digest decipher.key = (D_1 + D_2) decipher.iv = D_3 plain_text = decipher.update(payload) + decipher.final