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Are they encrypted in disk? How? Are they safe, for example, in the event of someone booting from a Live CD and mounting the hard disk?

How is the encryption key generated? Is it different in Windows and Linux?

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Note that Google refused to implement a master password (as Firefox has) because it would create a false sense of security, and there are tools like Chromepass that can decrypt the passwords database, provided the user is logged in. –  Dan Dascalescu Dec 3 '12 at 13:54

5 Answers 5

The passwords are encrypted and stored in a SQLite database:

The important piece here is CryptProtectData, which is a Windows API function for encrypting data. Data encrypted with this function is pretty solid. It can only be decrypted on the same machine and by the same user that encrypted it in the first place.

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But how is the encryption key generated? Depending on this I would consider the scheme more or less secure. And what about Linux? –  Óscar May 29 '10 at 18:39
    
@Óscar: On Windows, CryptProtectData uses your Windows credentials (not the password, but some other data) as the key. AFAIK, it's the same function used to protect your certificates, network credentials and all that stuff. –  grawity May 29 '10 at 19:23
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@Óscar: On Linux, Encryptor::EncryptString does not do anything. There seems to be code for using GNOME Keyring and KDE Wallet. –  grawity May 29 '10 at 19:38
    
Correct. On Linux, KDE Wallet, GNOME Keyring, or one other supported native password store (which I forget offhand) is used instead. –  Michael Hampton Oct 7 '12 at 23:47
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so...it seems it is possible to have another separate app that basically snoops your chrome passwords, given that you're already logged in and it's running as you? –  rogerdpack Nov 26 '12 at 20:35

They are "encrypted" but it's a reversable encryption. Chrome has to send the raw password to the site it was stored for, so if Chrome can decrypt and use it, so can other people. Storing passwords is never 100% safe.

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But which is the encryption key? –  Óscar May 29 '10 at 18:38
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Check the answer of sblair. Note that there is a possibility of decryption, no matter how it is stored. With the proper software, anyone could decrypt it. When you have logged into your Windows account until the moment you log out, your passwords are completely usable and completely viewable. Just indicating that there is not a 100% safe solution of storing browser passwords. –  BloodPhilia May 29 '10 at 18:39
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No but if your computer is hijacked/infected, browser passwords could easily be recovered without you noticing. Once again, all I'm pointing out is that there's no 100% failproof password storage for browsers... Just answering your question about their safety. –  BloodPhilia May 29 '10 at 18:48
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There is no "master password". CryptProtectData is a Windows API, Windows actually does all the encryption and retrieval, the encryption key is dependent on your user account and system. –  BloodPhilia May 29 '10 at 18:52
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This should provide you with an explanation of its workings: msdn.microsoft.com/en-us/library/ms995355.aspx –  BloodPhilia May 29 '10 at 19:02

You seem to be curious specifically about the key used to encrypt the passwords in Chrome.

The answer is:

Every password is encrypted with a different random key.

And then the encrypted password is stored in the SQLite database file:

%LocalAppData%\Google\Chrome\User Data\Default\Login Data

You can use something like SQLite Database Browser or SQLite Maestro to view it. Here's a snippet from my Login Data file:

origin_url                                username_value               password_value
========================================  ==============               ========================
http://thepiratebay.org/register          JolineBlomqvist@example.com  01000000D08C9DDF0115D1118C7A00C04FC297EB01000000BB0E1F4548ADC84A82EC0873552BCB460000000002000000000003660000C0000000100000006811169334524F33D880DE0C842B9BBB0000000004800000A00000001000000043C8E23979F5CC5499D73610B969A92A08000000EE07953DEC9F7CA01400000098B5F0F01E35B0DC6BBAFC53A9B1254AC999F4FA

You'll notice the password is an encrypted blob of data. The approximate algorithm to encrypt a new password is:

  • generate a new random session key
  • encrypt the password with the session key
  • encrypt the session key with the user's RSA public key
  • generate a Message Authentication Code (HMAC) for the encrypted data
  • concatenate the encrypted session key, the encrypted password, and the MAC

And Chrome saves that blob to its SQLite database.

But to answer your question: Where does the encryption key come from?

Each password is encrypted with a different randomly generated key

The Technical Details

Of course i left out the technical details. Chrome does not encrypt your passwords itself. Chrome does not have a master key used to encrypt anything. Chrome does not do the encryption. Windows does.

There is a Windows function, CryptProtectData, which is used to encrypt any arbitrary data you like. The details of calling it is less important. But if i invent a pseudo-language that somewhat can be decipherable as any programming languge, Chrome calls:

CryptProtectData(
      { cbData: 28, pbData: "correct battery horse staple" },
      "The password for superuser.com and all the glee therein",
      null, //optional entropy
      null, //reserved
      null, //prompt options
      0, //flags
      { cbData:   pbData:  }); //where the encrypted data will go

So the password:

  • Plaintext: correct battery horse staple
  • Encrypted: 01000000D08C9DDF0115D1118C7A00C04FC297EB01000000BB0E1F4548ADC84A82EC0873552BCB460000000002000000000003660000C0000000100000006811169334524F33D880DE0C842B9BBB0000000004800000A00000001000000043C8E23979F5CC5499D73610B969A92A08000000EE07953DEC9F7CA01400000098B5F0F01E35B0DC6BBAFC53A9B1254AC999F4FA

You'll notice that i never needed to supply a password. That is because Windows takes care of all of that. In the end:

  • a random password is generated to encrypt the password
  • that password is encrypted with a random password
  • that password is encrypted with your Windows password

So the only way for someone to know your password is if they know your password.

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How does chrome know the key to be able to use it to decript the stored password, then? –  brunoais Oct 18 '13 at 8:31
    
@brunoais Chrome does not know the key used to encrypt passwords. Chrome does not decrypt them - Windows does. –  Ian Boyd Oct 19 '13 at 16:28
    
Ah, ok. So if a malicious program gets into the computer the passwords are completely available to that program, right? –  brunoais Oct 19 '13 at 18:26
    
@brunoais Only if you've typed in your password. Unfortunately this is a fundamental limitation of encryption: once data is decrypted it is decrypted. –  Ian Boyd Oct 19 '13 at 19:26

Google Chrome encrypts passwords and stores them in SQLite DB but they could be easily viewed with the special password recovery applications such as ChromePass (http://www.nirsoft.net/utils/chromepass.html) or SecurePassword Kit (http://www.getsecurepassword.com/)

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I wonder if Chrome really stores passwords locally. I installed Chrome in a brand new computer and I am surprised it "remembers" my login credentials to several websites meaning, the data must be online on the Google cloud...

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