def raw_bcrypt(password, ident, salt, log_rounds):
"""perform central password hashing step in bcrypt scheme.
:param password: the password to hash
:param ident: identifier w/ minor version (e.g. 2, 2a)
:param salt: the binary salt to use (encoded in bcrypt-base64)
:param log_rounds: the log2 of the number of rounds (as int)
:returns: bcrypt-base64 encoded checksum
"""
# ===================================================================
# parse inputs
# ===================================================================
# parse ident
assert isinstance(ident, native_string_types)
add_null_padding = True
if ident == u('2a') or ident == u('2y') or ident == u('2b'):
pass
elif ident == u('2'):
add_null_padding = False
elif ident == u('2x'):
raise ValueError("crypt_blowfish's buggy '2x' hashes are not "
"currently supported")
else:
raise ValueError("unknown ident: %r" % (ident, ))
# decode & validate salt
assert isinstance(salt, bytes)
salt = bcrypt64.decode_bytes(salt)
if len(salt) < 16:
raise ValueError("Missing salt bytes")
elif len(salt) > 16:
salt = salt[:16]
# prepare password
assert isinstance(password, bytes)
if add_null_padding:
password += BNULL
# validate rounds
if log_rounds < 4 or log_rounds > 31:
raise ValueError("Bad number of rounds")
# ===================================================================
#
# run EKS-Blowfish algorithm
#
# This uses the "enhanced key schedule" step described by
# Provos and Mazieres in "A Future-Adaptable Password Scheme"
# http://www.openbsd.org/papers/bcrypt-paper.ps
#
# ===================================================================
engine = BlowfishEngine()
# convert password & salt into list of 18 32-bit integers (72 bytes total).
pass_words = engine.key_to_words(password)
salt_words = engine.key_to_words(salt)
# truncate salt_words to original 16 byte salt, or loop won't wrap
# correctly when passed to .eks_salted_expand()
salt_words16 = salt_words[:4]
# do EKS key schedule setup
engine.eks_salted_expand(pass_words, salt_words16)
# apply password & salt keys to key schedule a bunch more times.
rounds = 1 << log_rounds
engine.eks_repeated_expand(pass_words, salt_words, rounds)
# encipher constant data, and encode to bytes as digest.
data = list(BCRYPT_CDATA)
i = 0
while i < 6:
data[i], data[i + 1] = engine.repeat_encipher(data[i], data[i + 1], 64)
i += 2
raw = digest_struct.pack(*data)[:-1]
return bcrypt64.encode_bytes(raw)
def raw_bcrypt(password, ident, salt, log_rounds):
"""perform central password hashing step in bcrypt scheme.
:param password: the password to hash
:param ident: identifier w/ minor version (e.g. 2, 2a)
:param salt: the binary salt to use (encoded in bcrypt-base64)
:param log_rounds: the log2 of the number of rounds (as int)
:returns: bcrypt-base64 encoded checksum
"""
#===================================================================
# parse inputs
#===================================================================
# parse ident
assert isinstance(ident, native_string_types)
add_null_padding = True
if ident == u('2a') or ident == u('2y') or ident == u('2b'):
pass
elif ident == u('2'):
add_null_padding = False
elif ident == u('2x'):
raise ValueError("crypt_blowfish's buggy '2x' hashes are not "
"currently supported")
else:
raise ValueError("unknown ident: %r" % (ident,))
# decode & validate salt
assert isinstance(salt, bytes)
salt = bcrypt64.decode_bytes(salt)
if len(salt) < 16:
raise ValueError("Missing salt bytes")
elif len(salt) > 16:
salt = salt[:16]
# prepare password
assert isinstance(password, bytes)
if add_null_padding:
password += BNULL
# validate rounds
if log_rounds < 4 or log_rounds > 31:
raise ValueError("Bad number of rounds")
#===================================================================
#
# run EKS-Blowfish algorithm
#
# This uses the "enhanced key schedule" step described by
# Provos and Mazieres in "A Future-Adaptable Password Scheme"
# http://www.openbsd.org/papers/bcrypt-paper.ps
#
#===================================================================
engine = BlowfishEngine()
# convert password & salt into list of 18 32-bit integers (72 bytes total).
pass_words = engine.key_to_words(password)
salt_words = engine.key_to_words(salt)
# truncate salt_words to original 16 byte salt, or loop won't wrap
# correctly when passed to .eks_salted_expand()
salt_words16 = salt_words[:4]
# do EKS key schedule setup
engine.eks_salted_expand(pass_words, salt_words16)
# apply password & salt keys to key schedule a bunch more times.
rounds = 1<<log_rounds
engine.eks_repeated_expand(pass_words, salt_words, rounds)
# encipher constant data, and encode to bytes as digest.
data = list(BCRYPT_CDATA)
i = 0
while i < 6:
data[i], data[i+1] = engine.repeat_encipher(data[i], data[i+1], 64)
i += 2
raw = digest_struct.pack(*data)[:-1]
return bcrypt64.encode_bytes(raw)