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The "MasterPassphrase" page has been changed by GregStein: http://wiki.apache.org/subversion/MasterPassphrase?action=diff&rev1=24&rev2=25 Comment: detail the master password validation approach The encryption algorithm requires a 16 byte key (technically, it can also be 24 or 32 bytes), and a 16 byte [[http://en.wikipedia.org/wiki/Initialization_vector|initialization vector]]. The crypt key will be constructed as a derivation of the master password (see [[http://en.wikipedia.org/wiki/PBKDF2|PBKDF2]]). PBKDF2 requires a 64 bit salt. The IV is a random 16 byte value. The salt and IV will be stored within the block of data encrypted by the master password. The master password decrypts that data block, uses the salt to generate the (de)crypt key, then pairs it with the IV to decrypt the target password. - To provide master passphrase validation (for the purposes of changing passwords, for example), we'll store the master passphrase -- encrypted using itself. Verification of the master passphrase being tested then simply involves using it to decrypt the stored encrypted version of the real master passphrase and checking that the resulting plaintext matches the tested input. + To provide master passphrase validation (for the purposes of changing passwords, for example), we'll do the following: + {{{ + stuff = generate_random(len=32) + IV = generate_random(len=16) + salt = generate_random(len=8) + check_value = sha1(stuff) + encrypted = aes256cbc_encrypt(stuff, IV, PBKDF2(master, salt)) + save(encrypted, IV, salt, check_value) + + ... + + encrypted, IV, salt, check_value = load() + stuff = aes256cbc_decrypt(encrypted, IV, PBKDF2(master, salt)) + valid = sha1(stuff) == check_value + }}} + + Note that the above algorithm is similar to how we actually store target passwords (substitute the password for `stuff` with appropriate prefixing and padding). == Benefits == * Centralization: Rather than spread repository credentials cross a variety of stores (on-disk, keystores, etc.), we return to a single, easy-to-manage storage solution: the on-disk store in {{{~/.subversion/auth/}}}
