如何解密pbkdf2加密文本，不知道IV [英] How to decrypt pbkdf2 encrypted text without knowing the IV

问题描述

我正在尝试解密加密的文本。
我有盐值，迭代次数和密钥长度。但是我没有初始化向量（IV）值，我该怎么去解密呢？我也有秘密密钥。

暂时我正在使用大小为16字节的随机IV值。
但是我仍然无法正确解密该值。
任何人都可以帮忙，因为我很久以来一直呆在这里？

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以下是给了我。

  salt = EW0h0yUcDX72WU9UiKiCwDpXsJg =，迭代= 128，Keylenght = 16。 
 MasterKeyName = Passphrase1，MACMethod ALGO = HMAC-SHA1，麦基= JQ / NdikC7AZf0Z + HEL5NrCICV8XW + ttzl / 8687hVGHceoyJAaFws + 111plQH 6Mlg 加密KAE = pM7VB / KomPjq2cKaxPr5cKT1tUZN5tGMI + u1XKJTG1la + ThraPpLKlL2plKk6vQE 和valuemac =LBU + 9OcLArnj6mS7KYOKDa4zRU0 =。 
秘密密钥=xxxxxxxxxxx。 
  

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下面是我用来解密的代码。

  SecretKeyFactory factory = SecretKeyFactory.getInstance（PBKDF2WithHmacSHA1）; 
 KeySpec spec = new PBEKeySpec（secretkey.toCharArray（），salt，iterationCount，keyStrength）; 
 SecretKey tmp = factory.generateSecret（spec）; 
 key = new SecretKeySpec（tmp.getEncoded（），AES）; 
 dcipher = Cipher.getInstance（AES / CBC / PKCS5Padding）; 
 AlgorithmParameters params = dcipher.getParameters（）; 
 iv =0000000000000000.getBytes（）; 
 System.out.println（IV+ new sun.misc.BASE64Encoder（）。encodeBuffer（iv））; 
 dcipher.init（Cipher.DECRYPT_MODE，key，new IvParameterSpec（iv））; 
 byte [] decryptptedData = new sun.misc.BASE64Decoder（）。decodeBuffer（base64EncryptedData）; 
 byte [] utf8 = dcipher.doFinal（decryptptedData）; 
  

解决方案

您无法解密第一个 CBC加密密文块，如果你不知道IV。

然而，您不太可能可以检索IV值：

• 通常，从PBKDF生成的关键字节之后，IV值是16字节检索;


• 通常将IV置于密文之前，导致一个解密前的全部明文之前的垃圾;


• 不安全，但IV也被省略或设置为常数值，全零IV是最常见的（这是相同的CBC模式不使用任何IV。）

I am trying to decrypt an encrypted text. I have the salt value, iteration count and key length. But i don't have the initialization vector (IV) value, how can i go about and decrypt this. I also have secret key.

For time being I am using some random IV value whose size is 16 bytes. But still i am not able to decrypt the value properly. Can anyone please help as i am stuck with this for a long time?

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Below are the values which were given to me.

salt= EW0h0yUcDX72WU9UiKiCwDpXsJg=, Iteration=128,Keylenght=16.
MasterKeyName="Passphrase1", MACMethod algo = hmac-sha1,    MACKey="jq/NdikC7AZf0Z+HEL5NrCICV8XW+ttzl/8687hVGHceoyJAaFws+111plQH 6Mlg" encrypted kae =   "pM7VB/KomPjq2cKaxPr5cKT1tUZN5tGMI+u1XKJTG1la+ThraPpLKlL2plKk6vQE"   and valuemac="lbu+9OcLArnj6mS7KYOKDa4zRU0=".
Secret key = "xxxxxxxxxxx".

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Below is the code which I am using to decrypt.

SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
KeySpec spec = new PBEKeySpec(secretkey.toCharArray(), salt, iterationCount, keyStrength);    
SecretKey tmp = factory.generateSecret(spec);
key = new SecretKeySpec(tmp.getEncoded(), "AES");
dcipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
AlgorithmParameters params = dcipher.getParameters();
iv = "0000000000000000".getBytes();
System.out.println("IV " + new sun.misc.BASE64Encoder().encodeBuffer(iv));
dcipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(iv));      
byte[] decryptedData = new sun.misc.BASE64Decoder().decodeBuffer(base64EncryptedData);
byte[] utf8 = dcipher.doFinal(decryptedData);

解决方案

You cannot decrypt the first block of CBC encrypted ciphertext if you don't know the IV.

It is however not unlikely that you can retrieve the IV value:

• often the IV value is 16 bytes retrieved after the key bytes) generated from the PBKDF;
• the IV is often prepended to the ciphertext, resulting in one block of garbage before the full plaintext during decryption;
• not secure but the IV is also left out or set to a constant value, with an all-zero IV being the most common (this is identical in CBC mode to not using any IV.)

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