def pbkdf2(password, salt=None, i=10000, keylen=64):
"""Key derivation function using SHA256"""
if salt is None:
salt = OpenSSL.rand(8)
p_password = OpenSSL.malloc(password, len(password))
p_salt = OpenSSL.malloc(salt, len(salt))
output = OpenSSL.malloc(0, keylen)
OpenSSL.PKCS5_PBKDF2_HMAC(p_password, len(password), p_salt, len(p_salt),
i, OpenSSL.EVP_sha256(), keylen, output)
return salt, output.raw
def hmac_sha256(k, m):
"""
Compute the key and the message with HMAC SHA5256
"""
key = OpenSSL.malloc(k, len(k))
d = OpenSSL.malloc(m, len(m))
md = OpenSSL.malloc(0, 32)
i = OpenSSL.pointer(OpenSSL.c_int(0))
OpenSSL.HMAC(OpenSSL.EVP_sha256(), key, len(k), d, len(m), md, i)
return md.raw
