Linux scrypt shared library.
Full credit to algorithm designer and example code from Colin Percival here: http://www.tarsnap.com/scrypt.html
Utilises BSD licensed BASE64 encoder here: http://code.google.com/p/stringencoders/
Official project page, including stable tarballs found here: http://www.lolware.net/libscrypt.html
Simple hashing interface
A hash can be generated using the following function:
int libscrypt_scrypt(char *dst, char *passphrase, uint32_t N, uint8_t r, uint8_t p)
Sane constants have been created for N, r and p so you can create a has like this:
libscrypt_scrypt(outbuf, "My cats's breath smells like cat food", SCRYPT_N, SCRYPT_r, SCRYPT_p);
Output stored in "outbuf" is stored in a standardised MCF form, which means includes the randomly created, 128 bit salt, all N, r and p values, and a BASE64 encoded version of the hash. The entire MCF can be stored in a database, and compared for use as below:
retval = scrypt_check(mcf, "pleasefailme");
retval < 0 error
retval = 0 password incorrect
retval > 0 pass
mcf should be defined as at least SCRYPT_MCF_LEN in size.
A number of internal functions are exposed, and users wishing to create more complex use cases should consult the header file, which is aimed at documenting the API fully.
make
make check
Check the Makefile for advice on linking against your application.
SCRYPT_* constants are probably a little high for something like a Raspberry pi. Using '1' as SCRYPT_p is acceptable from a security and performance standpoint if needed.
Code is now declared "stable", the master branch will always be "stable" and development will be done on branches. The reference machines are Fedora, CentOS, FreeBSD and Raspbian, and the code is expected to compile and run on all of these before being moved to stable branch. Testing has also confirmed that libscrypt does compile and run on MacOS with minor Makefile edits. Full transparancy on the regular application of thorough testing can be found by reviewing recent test harness results here: http://www.lolware.net/libscrypttesting.txt
v1.1a: Single Makefile line change. I wouldn't ordinarily tag this as a new "release", but the purpose here is to assist with packaging in distributions.
v1.12: The static library is built, but no longer installed by default. You can install it with "make install-static". This is because static libraries are not typically bundled in packages.
v1.13: Minor packaging related update