It has exploded in a bunch of git-repos:

• libsphinx: low-level c library
• ed448goldilocks: cross-compile with mingw for windows
• pwdsphinx: python-wrapper around libsphinx, including client/server
• websphinx-chrom: webextension for chrom/opera
• websphinx-firefox: webextension for firefox
• winsphinx: build a package on linux for compiling a windows installer on windows

libdecaf-based sphinx password storage implementation

sphinx: a password Store that Perfectly Hides from Itself (No Xaggeration)

pitchforked sphinx is a cryptographic password storage as described in https://eprint.iacr.org/2015/1099

and as presented by the Levchin Prize winner 2018 Hugo Krawczyk on Real World Crypto https://www.youtube.com/watch?v=px8hiyf81iM

pitchforked sphinx comes with variety of interfaces: a library, a python wrapper around that library, a network server/client written in python and simple command-line binaries.

It allows you to have only a few (at least one) passwords that you need to remember, while at the same time provides unique 40 (ASCII) character long very random passwords (256 bit entropy). Your master password is encrypted (blinded) and sent to the password storage server which (without decrypting) combines your encrypted password with a big random number and sends this (still encrypted) back to you, where you can decrypt it (it's a kind of end-to-end encryption of passwords) and use the resulting unique, strong and very random password to register/login to various services. The resulting strong passwords make offline password cracking attempts infeasible. If say you use this with google and their password database is leaked your password will still be safe.

How is this different from my password storage which stores the passwords in an encrypted database? Most importantly using an encrypted database is not "end-to-end" encrypted. Your master password is used to decrypt the database read out the password and send it back to you. This means whoever has your database can try to crack your master password on it, or can capture your master password while you type or send it over the network. Then all your passwords are compromised. If some attacker compromises your traditional password store it's mostly game over for you. Using sphinx the attacker controlling your password store learns nothing about your master nor your individual passwords. Also even if your strong password leaks, it's unique and cannot be used to login to other sites or services.

Install libsodium using your operating system provided package management. And if you use any of the python goodies you need to install also pysodium using either your OS package manager or pip.

Building everything should be quite simple afterwards:

git submodule init
make

Pitchforked sphinx builds a library, which you can use to build your own password manager either in C/C++ or any other language that can bind to this library. The library also contains an experimental version of the PKI-free PAKE protocol from page 18 of the paper.

The Library exposes the following 3 functions for the FK-PTR protocol (the password storage):

void challenge(const uint8_t *pwd, const size_t p_len, uint8_t *bfac, uint8_t *chal);

• pwd, p_len: are input params, containing the master password and its length
• bfac: is an output param, it's a pointer to an array of DECAF_255_SCALAR_BYTES (32) bytes - the blinding factor
• chal: is an output param, it's a pointer to an array of DECAF_255_SER_BYTES (32) bytes - the challenge

int respond(const uint8_t *chal, const uint8_t *secret, uint8_t *resp);

• chal: is an input param, it is the challenge from the challenge() function, it has to be a DECAF_255_SER_BYTES (32) bytes big array
• secret: is an input param, it is the "secret" contribution from the device, it is a DECAF_255_SCALAR_BYTES (32) bytes long array
• resp: is an output parameter, it is the result of this step, it must be a DECAF_255_SER_BYTES (32) byte sized array
• the function returns 1 on error, 0 on success

int finish(const uint8_t *bfac, const uint8_t *resp, uint8_t *rwd);

• bfac: is an input param, it is the bfac output from challenge(), it is array of DECAF_255_SCALAR_BYTES (32) bytes
• resp: is an input parameter, it's the response from respond(), it is a DECAF_255_SER_BYTES (32) byte sized array
• rwd: is an output param, the derived (binary) password, it is a DECAF_255_SER_BYTES (32) byte array
• this function returns 1 on error, 0 on success

The following functions implement the PKI-free PAKE protocol, (for the explanation of the various parameters please see the original paper and the pake-test.c example file):

void server_init(uint8_t *p_s, uint8_t *P_s);

This function is called when setting up a new server. It creates a long-term identity keypair. The public key needs to be shared with all clients, the secret key needs to be well protected and persisted for later usage.

void client_init(const uint8_t *rwd, const size_t rwd_len,
                 const uint8_t *P_s,
                 uint8_t k_s[32], uint8_t c[32],
                 uint8_t C[32], uint8_t P_u[32], uint8_t m_u[32]);

This function needs to be run on the client when registering at a server. The output parameters need to be sent to the server.

void start_pake(const uint8_t *rwd, const size_t rwd_len,
                uint8_t alpha[32], uint8_t x_u[32],
                uint8_t X_u[32], uint8_t sp[32]);

The client initiates a "login" to the server with this function.

int server_pake(const uint8_t alpha[32], const uint8_t X_u[32],  // input params
                const uint8_t k_s[32], const uint8_t P_u[32],
                const uint8_t p_s[32],
                uint8_t beta[32], uint8_t X_s[32],               // output params
                uint8_t SK[DECAF_X25519_PUBLIC_BYTES]);

This function implements the "login" on the server, it reuses the data received when registering the user, and some other parameters that came out of start_pake() when the client initiated the "login". At successful completion SK should be a shared secret with the client. On error the function return 1, otherwise 0.

int user_pake(const uint8_t *rwd, const size_t rwd_len, const uint8_t sp[32],
              const uint8_t x_u[32], const uint8_t beta[32], const uint8_t c[32],
              const uint8_t C[32], const uint8_t P_u[32], const uint8_t m_u[32],
              const uint8_t P_s[32], const uint8_t X_s[32],
              uint8_t SK[DECAF_X25519_PUBLIC_BYTES]);

This function finalizes the "login" on the client side. At successful completion SK should be a shared secret with the server. On error the function return 1, otherwise 0.

pitchforked sphinx comes with very simple binaries, so you can build your own password storage even from shell scripts. Each step in the protocol is handled by one binary:

The following creates a challenge for a device:

echo -n "shitty master password" | ./challenge >c 2>b

The master password is passed in through standard input.

The challenge is sent to standard output.

A blinding factor is stored in a tempfile, the name of this file is output to stderr. This tempfile is needed in the last step again.

Pass the challenge from step 1 on standard input like:

./respond secret <c >r0

The response is sent to standard output.

To derive a (currently hex) password, pass the response from step 2 on standard input and the filename of the tempfile from step 1 like:

fname=$(cat b)
./derive $fname <r0 >pwd0

The derived password is sent to standard output and currently is a 32 byte binary string.

The output from step 3 is a 32 byte binary string, most passwords have some limitations to accept only printable - ASCII - chars. bin2pass.py is a python script which takes a binary input on standard input and transforms it into an ASCII password. It can have max two parameters the classes of characters allowed ([u]pper-, [l]ower-case letters, [d]igits and [s]ymbols) and the size of the password. The following examples should make this clear:

Full ASCII, max size:

./bin2pass.py <pwd0

no symbols, max size:

./bin2pass.py uld <pwd0

no symbols, 8 chars:

./bin2pass.py uld 8 <pwd0

only digits, 4 chars:

./bin2pass.py d 4 <pwd0

only letters, 16 chars:

./bin2pass.py ul 16 <pwd0