Add encryption helpers

Jeff Lai
1 parent 526b4bcc
Showing 2 changed files with 72 additions and 0 deletions Show diff stats
lib/dingtalk/pkcs7_encoder.rb
lib/dingtalk/prpcrypt.rb
@@ -0,0 +1,26 @@
+module Dingtalk
+  module PKCS7Encoder
+    extend self
+
+    BLOCK_SIZE = 32
+
+    def decode(text)
+      pad = text[-1].ord
+      pad = 0 if (pad < 1 || pad > BLOCK_SIZE)
+      size = text.size - pad
+      text[0...size]
+    end
+
+    # 对需要加密的明文进行填充补位
+    # 返回补齐明文字符串
+    def encode(text)
+      # 计算需要填充的位数
+      amount_to_pad = BLOCK_SIZE - (text.length % BLOCK_SIZE)
+      amount_to_pad = BLOCK_SIZE if amount_to_pad == 0
+      # 获得补位所用的字符
+      pad_chr = amount_to_pad.chr
+      "#{text}#{pad_chr * amount_to_pad}"
+    end
+
+  end
+end
@@ -0,0 +1,46 @@
+module Dingtalk
+  module Prpcrypt
+    extend self
+
+    # 对密文进行解密.
+    # text 需要解密的密文
+    def decrypt(aes_key, text, corpid)
+      status = 200
+      text        = Base64.decode64(text)
+      text        = handle_cipher(:decrypt, aes_key, text)
+      result      = PKCS7Encoder.decode(text)
+      content     = result[16...result.length]
+      len_list    = content[0...4].unpack("N")
+      xml_len     = len_list[0]
+      xml_content = content[4...4 + xml_len]
+      from_corpid = content[xml_len+4...content.size]
+      # TODO: refactor
+      if corpid != from_corpid
+        Rails.logger.debug("#{__FILE__}:#{__LINE__} Failure because #{corpid} != #{from_corpid}")
+        status = 401
+      end
+      [xml_content, status]
+    end
+
+    # 加密
+    def encrypt(aes_key, text, corpid)
+      text    = text.force_encoding("ASCII-8BIT")
+      random  = SecureRandom.hex(8)
+      msg_len = [text.length].pack("N")
+      text    = "#{random}#{msg_len}#{text}#{corpid}"
+      text    = PKCS7Encoder.encode(text)
+      text    = handle_cipher(:encrypt, aes_key, text)
+      Base64.encode64(text)
+    end
+
+    private
+      def handle_cipher(action, aes_key, text)
+        cipher = OpenSSL::Cipher.new('AES-256-CBC')
+        cipher.send(action)
+        cipher.padding = 0
+        cipher.key     = aes_key
+        cipher.iv      = aes_key[0...16]
+        cipher.update(text) + cipher.final
+      end
+  end
+end
@@ -0,0 +1,26 @@		@@ -0,0 +1,26 @@
	1	+module Dingtalk
	2	+ module PKCS7Encoder
	3	+ extend self
	4	+
	5	+ BLOCK_SIZE = 32
	6	+
	7	+ def decode(text)
	8	+ pad = text[-1].ord
	9	+ pad = 0 if (pad < 1 \|\| pad > BLOCK_SIZE)
	10	+ size = text.size - pad
	11	+ text[0...size]
	12	+ end
	13	+
	14	+ # 对需要加密的明文进行填充补位
	15	+ # 返回补齐明文字符串
	16	+ def encode(text)
	17	+ # 计算需要填充的位数
	18	+ amount_to_pad = BLOCK_SIZE - (text.length % BLOCK_SIZE)
	19	+ amount_to_pad = BLOCK_SIZE if amount_to_pad == 0
	20	+ # 获得补位所用的字符
	21	+ pad_chr = amount_to_pad.chr
	22	+ "#{text}#{pad_chr * amount_to_pad}"
	23	+ end
	24	+
	25	+ end
	26	+end
@@ -0,0 +1,46 @@		@@ -0,0 +1,46 @@
	1	+module Dingtalk
	2	+ module Prpcrypt
	3	+ extend self
	4	+
	5	+ # 对密文进行解密.
	6	+ # text 需要解密的密文
	7	+ def decrypt(aes_key, text, corpid)
	8	+ status = 200
	9	+ text = Base64.decode64(text)
	10	+ text = handle_cipher(:decrypt, aes_key, text)
	11	+ result = PKCS7Encoder.decode(text)
	12	+ content = result[16...result.length]
	13	+ len_list = content[0...4].unpack("N")
	14	+ xml_len = len_list[0]
	15	+ xml_content = content[4...4 + xml_len]
	16	+ from_corpid = content[xml_len+4...content.size]
	17	+ # TODO: refactor
	18	+ if corpid != from_corpid
	19	+ Rails.logger.debug("#{__FILE__}:#{__LINE__} Failure because #{corpid} != #{from_corpid}")
	20	+ status = 401
	21	+ end
	22	+ [xml_content, status]
	23	+ end
	24	+
	25	+ # 加密
	26	+ def encrypt(aes_key, text, corpid)
	27	+ text = text.force_encoding("ASCII-8BIT")
	28	+ random = SecureRandom.hex(8)
	29	+ msg_len = [text.length].pack("N")
	30	+ text = "#{random}#{msg_len}#{text}#{corpid}"
	31	+ text = PKCS7Encoder.encode(text)
	32	+ text = handle_cipher(:encrypt, aes_key, text)
	33	+ Base64.encode64(text)
	34	+ end
	35	+
	36	+ private
	37	+ def handle_cipher(action, aes_key, text)
	38	+ cipher = OpenSSL::Cipher.new('AES-256-CBC')
	39	+ cipher.send(action)
	40	+ cipher.padding = 0
	41	+ cipher.key = aes_key
	42	+ cipher.iv = aes_key[0...16]
	43	+ cipher.update(text) + cipher.final
	44	+ end
	45	+ end
	46	+end