Split Sodium::Pwhash in to Sodium::Password::Hash and Sodium::Password::Key.

master
Didactic Drunk 2019-09-16 01:49:55 -07:00
parent fbb7e9434a
commit b4fe9ef1c3
10 changed files with 515 additions and 353 deletions

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require "../spec_helper"
require "../../src/sodium/password"
require "../../src/sodium/kdf"
require "json"
def test_vectors(filename, pwmode)
pwhash = Sodium::Password::Hash.new
pwkey = Sodium::Password::Key.new
buf = File.read Path[__DIR__].join("..", "data", filename)
vectors = Array(Hash(String, String | Int32)).from_json(buf).map do |h|
{
salt: h["salt"].to_s,
pass: h["passwd"].to_s,
mode: h["mode"].to_s,
ops: h["iters"].to_i,
mem: h["maxmem"].to_i * 1024,
dgst_len: h["dgst_len"].to_i,
hash: h["pwhash"].to_s,
# h: h,
}
end
vectors.each do |h|
case h[:mode]
when "argon2i"
pwhash.verify h[:hash], h[:pass]
when "argon2id"
pwhash.verify h[:hash], h[:pass]
when "raw"
pwkey.ops = h[:ops].to_u64
pwkey.mem = h[:mem].to_u64
pwkey.mode = pwmode
# p pwhash, h
key = pwkey.derive_key h[:pass], h[:dgst_len], salt: h[:salt].to_slice
key.should eq h[:hash].hexbytes
else
# p h
puts "unhandled mode #{h[:mode]}"
next
# raise "unhandled mode #{h[:mode]}"
end
end
end
private def pw_min
pwhash = Sodium::Password::Hash.new
# set to minimum to speed up tests
pwhash.mem = Sodium::Password::MEMLIMIT_MIN
pwhash.ops = Sodium::Password::OPSLIMIT_MIN
pwhash
end
private def pk_min
pwkey = Sodium::Password::Key.new
# set to minimum to speed up tests
pwkey.mem = Sodium::Password::MEMLIMIT_MIN
pwkey.ops = Sodium::Password::OPSLIMIT_MIN
pwkey
end
describe Sodium::Password::Hash do
it "hashes and verifies a password" do
pwhash = pw_min
pass = "1234"
hash = pwhash.create pass
pwhash.verify hash, pass
expect_raises(Sodium::Password::Error::Verify) do
pwhash.verify hash, "5678"
end
pwhash.needs_rehash?(hash).should be_false
p pwhash
pwhash.ops = Sodium::Password::OPSLIMIT_MAX
p pwhash
pwhash.needs_rehash?(hash).should be_true
end
it "PyNaCl key vectors" do
test_vectors "modular_crypt_argon2i_hashes.json", Sodium::Password::Mode::Argon2i13
test_vectors "modular_crypt_argon2id_hashes.json", Sodium::Password::Mode::Argon2id13
test_vectors "raw_argon2i_hashes.json", Sodium::Password::Mode::Argon2i13
test_vectors "raw_argon2id_hashes.json", Sodium::Password::Mode::Argon2id13
end
# from libsodium/test/default/pwhash_argon2id.c
it "RbNaCl key vectors" do
pwhash = Sodium::Password::Key.new
pwhash.mode = Sodium::Password::Mode::Argon2id13
pwhash.ops = 5_u64
pwhash.mem = 7_256_678_u64
key_len = 155
pass = "a347ae92bce9f80f6f595a4480fc9c2fe7e7d7148d371e9487d75f5c23008ffae0" \
"65577a928febd9b1973a5a95073acdbeb6a030cfc0d79caa2dc5cd011cef02c08d" \
"a232d76d52dfbca38ca8dcbd665b17d1665f7cf5fe59772ec909733b24de97d6f5" \
"8d220b20c60d7c07ec1fd93c52c31020300c6c1facd77937a597c7a6".hexbytes
salt = "5541fbc995d5c197ba290346d2c559de".hexbytes
expected = "18acec5d6507739f203d1f5d9f1d862f7c2cdac4f19d2bdff64487e60d969e3ced6" \
"15337b9eec6ac4461c6ca07f0939741e57c24d0005c7ea171a0ee1e7348249d135b" \
"38f222e4dad7b9a033ed83f5ca27277393e316582033c74affe2566a2bea47f91f0" \
"fd9fe49ece7e1f79f3ad6e9b23e0277c8ecc4b313225748dd2a80f5679534a0700e" \
"246a79a49b3f74eb89ec6205fe1eeb941c73b1fcf1".hexbytes
key = pwhash.derive_key pass, key_len, salt: salt
key.should eq expected
end
end
describe Sodium::Password::Key::Create do
pending "derive_key fails without a mode" do
pwkey = pk_min
expect_raises(ArgumentError, /^missing mode$/) do
pwkey.derive_key "foo", 16
end
end
it "derive_key fails without a salt" do
pwkey = pk_min
expect_raises(ArgumentError, /^missing salt$/) do
pwkey.derive_key "foo", 16
end
end
it "derives a key from a password" do
pwkey = pk_min
pwkey.mode = Sodium::Password::Mode::Argon2id13
salt = pwkey.random_salt
key1 = pwkey.derive_key "foo", 16, salt: salt
key2 = pwkey.derive_key "foo", 16, salt: salt
key3 = pwkey.derive_key "bar", 16, salt: salt
key4 = pwkey.derive_key "foo", 16, salt: pwkey.random_salt
key1.bytesize.should eq 16
key1.should eq key2
key1.should_not eq key3
key1.should_not eq key4
end
it "derives a kdf from a password" do
pwkey = pk_min
pwkey.mode = Sodium::Password::Mode::Argon2id13
salt = pwkey.random_salt
kdf = pwkey.derive_kdf "foo", salt: salt
end
it "creates and derives a key from a passord based on time" do
pass = "1234"
context = "8bytesss"
ck = Sodium::Password::Key::Create.new
ck.tcost = 0.2
ck.mem_max = Sodium::Password::MEMLIMIT_MIN * 2
kdf1, params = ck.create_kdf pass
pw = Sodium::Password::Key.from_params params.not_nil!.to_h
kdf2 = nil
ts = Time.measure do
kdf2 = pw.derive_kdf pass
end
kdf2 = kdf2.not_nil!
# Check #create_kdf and #derive_kdf create the same subkeys
subkey1 = kdf1.derive context, 0, 16
subkey2 = kdf2.derive context, 0, 16
subkey1.should eq subkey2
# ts should be within +|- 10%. allow up to 20%
(ts.to_f - ck.tcost).abs.should be < (ck.tcost * 0.2)
end
pending "implement auth" do
end
end

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require "../spec_helper"
require "../../src/sodium/pwhash"
require "../../src/sodium/kdf"
require "json"
def test_vectors(filename, pwmode)
pwhash = Sodium::Pwhash.new
buf = File.read Path[__DIR__].join("..", "data", filename)
vectors = Array(Hash(String, String | Int32)).from_json(buf).map do |h|
{
salt: h["salt"].to_s,
pass: h["passwd"].to_s,
mode: h["mode"].to_s,
ops: h["iters"].to_i,
mem: h["maxmem"].to_i * 1024,
dgst_len: h["dgst_len"].to_i,
hash: h["pwhash"].to_s,
# h: h,
}
end
vectors.each do |h|
case h[:mode]
when "argon2i"
pwhash.mode = Sodium::Pwhash::Mode::Argon2i13
pwhash.verify h[:hash], h[:pass]
when "argon2id"
pwhash.mode = Sodium::Pwhash::Mode::Argon2id13
pwhash.verify h[:hash], h[:pass]
when "raw"
pwhash.opslimit = h[:ops].to_u64
pwhash.memlimit = h[:mem].to_u64
pwhash.mode = pwmode
# p pwhash, h
key = pwhash.derive_key salt: h[:salt].to_slice, pass: h[:pass], key_bytes: h[:dgst_len]
key.should eq h[:hash].hexbytes
else
# p h
puts "unhandled mode #{h[:mode]}"
next
# raise "unhandled mode #{h[:mode]}"
end
end
end
private def pw_min
pwhash = Sodium::Pwhash.new
# set to minimum to speed up tests
pwhash.memlimit = Sodium::Pwhash::MEMLIMIT_MIN
pwhash.opslimit = Sodium::Pwhash::OPSLIMIT_MIN
pwhash
end
describe Sodium::Pwhash do
it "hashes and verifies a password" do
pwhash = pw_min
pass = "1234"
hash = pwhash.create pass
pwhash.verify hash, pass
expect_raises(Sodium::Pwhash::PasswordVerifyError) do
pwhash.verify hash, "5678"
end
pwhash.needs_rehash?(hash).should be_false
pwhash.opslimit = Sodium::Pwhash::OPSLIMIT_MAX
pwhash.needs_rehash?(hash).should be_true
end
it "derive_key fails without a mode" do
pwhash = pw_min
expect_raises(ArgumentError) do
pwhash.derive_key pwhash.random_salt, "foo", 16
end
end
it "derives a key from a password" do
pwhash = pw_min
pwhash.mode = Sodium::Pwhash::Mode::Argon2id13
salt = pwhash.random_salt
key1 = pwhash.derive_key salt, "foo", 16
key2 = pwhash.derive_key salt, "foo", 16
key3 = pwhash.derive_key salt, "bar", 16
key4 = pwhash.derive_key pwhash.random_salt, "foo", 16
key1.bytesize.should eq 16
key1.should eq key2
key1.should_not eq key3
key1.should_not eq key4
end
it "derives a kdf from a password" do
pwhash = pw_min
pwhash.mode = Sodium::Pwhash::Mode::Argon2id13
salt = pwhash.random_salt
kdf = pwhash.derive_kdf salt, "foo", 32
end
it "creates a key and sets parameters by time" do
pwhash = pw_min
tcost = 0.2
pwhash.tcost = tcost
salt = pwhash.random_salt
key, pwcreate = pwhash.create_key salt, "foo", 32
pwcreate.memlimit.should be > pwhash.memlimit
pwcreate.opslimit.should be > pwhash.opslimit
ts = Time.measure do
key.should eq pwcreate.derive_key(salt, "foo", 32)
end
# ts should be within +|- 10%. allow up to 20%
(ts.to_f - tcost).abs.should be < (tcost * 0.2)
end
it "PyNaCl key vectors" do
test_vectors "modular_crypt_argon2i_hashes.json", Sodium::Pwhash::Mode::Argon2i13
test_vectors "modular_crypt_argon2id_hashes.json", Sodium::Pwhash::Mode::Argon2id13
test_vectors "raw_argon2i_hashes.json", Sodium::Pwhash::Mode::Argon2i13
test_vectors "raw_argon2id_hashes.json", Sodium::Pwhash::Mode::Argon2id13
end
# from libsodium/test/default/pwhash_argon2id.c
it "RbNaCl key vectors" do
pwhash = Sodium::Pwhash.new
pwhash.mode = Sodium::Pwhash::Mode::Argon2id13
pwhash.opslimit = 5_u64
pwhash.memlimit = 7_256_678_u64
key_len = 155
pass = "a347ae92bce9f80f6f595a4480fc9c2fe7e7d7148d371e9487d75f5c23008ffae0" \
"65577a928febd9b1973a5a95073acdbeb6a030cfc0d79caa2dc5cd011cef02c08d" \
"a232d76d52dfbca38ca8dcbd665b17d1665f7cf5fe59772ec909733b24de97d6f5" \
"8d220b20c60d7c07ec1fd93c52c31020300c6c1facd77937a597c7a6".hexbytes
salt = "5541fbc995d5c197ba290346d2c559de".hexbytes
expected = "18acec5d6507739f203d1f5d9f1d862f7c2cdac4f19d2bdff64487e60d969e3ced6" \
"15337b9eec6ac4461c6ca07f0939741e57c24d0005c7ea171a0ee1e7348249d135b" \
"38f222e4dad7b9a033ed83f5ca27277393e316582033c74affe2566a2bea47f91f0" \
"fd9fe49ece7e1f79f3ad6e9b23e0277c8ecc4b313225748dd2a80f5679534a0700e" \
"246a79a49b3f74eb89ec6205fe1eeb941c73b1fcf1".hexbytes
key = pwhash.derive_key salt, pass, key_len
key.should eq expected
end
end

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src/sodium/password.cr Normal file
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require "./lib_sodium"
require "./secure_buffer"
# [Argon2 Password Hashing](https://libsodium.gitbook.io/doc/password_hashing/the_argon2i_function)
# * #store #verify #needs_rehash? are used together for password verification.
# * #derive_key is used on it's own to generate password based keys.
#
# **See `examples/pwhash_selector.cr` for help on selecting parameters.**
#
# ## Creating a key for encryption with auto set parameters based on time.
#
module Sodium::Password
OPSLIMIT_MIN = LibSodium.crypto_pwhash_opslimit_min
OPSLIMIT_INTERACTIVE = LibSodium.crypto_pwhash_opslimit_interactive
OPSLIMIT_MODERATE = LibSodium.crypto_pwhash_opslimit_moderate
OPSLIMIT_SENSITIVE = LibSodium.crypto_pwhash_opslimit_sensitive
OPSLIMIT_MAX = LibSodium.crypto_pwhash_opslimit_max
MEMLIMIT_MIN = LibSodium.crypto_pwhash_memlimit_min
MEMLIMIT_INTERACTIVE = LibSodium.crypto_pwhash_memlimit_interactive
# Don't use this. Maximum of the library which is more ram than any computer.
MEMLIMIT_MAX = LibSodium.crypto_pwhash_memlimit_max
SALT_SIZE = LibSodium.crypto_pwhash_saltbytes
STR_SIZE = LibSodium.crypto_pwhash_strbytes
class Error < Exception
class Verify < Error
end
end
end
require "./password/**"

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require "../lib_sodium"
require "../secure_buffer"
abstract class Sodium::Password::Abstract
property ops = OPSLIMIT_INTERACTIVE
# Specified in bytes.
property mem = MEMLIMIT_INTERACTIVE
# Returns a random salt for use with #derive_key
def random_salt
Random::Secure.random_bytes SALT_SIZE
end
def self.from_params(hash)
pw = self.new
pw.ops = hash["ops"].as(UInt64)
pw.mem = hash["mem"].as(UInt64)
if pw.responds_to?(:mode=) && (mode = hash["mode"]?)
pw.mode = Mode.parse mode.as(String)
end
if pw.responds_to?(:salt=) && (salt = hash["salt"]?)
pw.salt = salt.as(Bytes)
end
if pw.responds_to?(:key_size=) && (key_size = hash["key_size"]?)
pw.key_size = key_size.as(Int32)
end
if pw.responds_to?(:tcost=) && (tcost = hash["tcost"]?)
pw.tcost = tcost.as(Float64)
end
if pw.responds_to?(:auth=) && (auth = hash["auth"]?)
pw.auth = auth.as(Bytes)
end
pw
end
end

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require "./key"
# [Argon2 Password Hashing](https://libsodium.gitbook.io/doc/password_hashing/the_argon2i_function)
#
# ## Create a key for encryption with auto set parameters based on time.
#
# Usage:
# ```
# pwkc = Sodium::Password::Key::Create.new
#
# # Take approximately 1 second to generate a key.
# pwkc.tcost = 1.0
#
# # Memory use will end up between `mem_min` and `mem_max`
# pwkc.mem_min = 128 * 1024 * 1024 # 128M
# pwkc.mem_max = 256 * 1024 * 1024 # 256M
#
# kdf, params = pwkc.create_kdf pass
# # Or
# key, params = pwkc.create_key pass, 32
#
# # Save params.[mode, ops, mem, salt, key_size] to derive the same key later.
# ```
#
# ## Deriving a previously created key.
#
# Usage:
# ```
# pwkey = Sodium::Password::Key.new
# pwkey.mode = Mode.parse serialized[:mode]
# pwkey.ops = serialized[:ops]
# pwkey.mem = serialized[:mem]
# pwkey.salt = serialized[:salt]
# key_size = serialized[:key_size]
#
# kdf = pwhash.derive_kdf pass
# # Or
# key = pwkey.derive_key pass, key_size
# ```
class Sodium::Password::Key::Create
# Specified in seconds.
property tcost = 0.1
# Specified in bytes.
# Currently the libsodium default. May increase between version.
property mem_min = MEMLIMIT_MIN
# Specified in bytes.
# Currently defaults to 256M. May increase between version.
property mem_max : UInt64 = 256_u64 * 1024 * 1024
property mode : Mode = Mode.default
# * the result of a memory-hard, CPU-intensive hash function applied to the password
# * the automatically generated salt used for the previous computation
# * the other parameters required to verify the password, including the algorithm identifier, its version, ops and mem.
# Returns a consistent key based on [salt, pass, key_size, mode] in a SecureBuffer **and** Params.
#
# Params are set to run in approximately `tcost` seconds.
#
# Make sure you store `Params` for later use with #derive_key.
def create_key(pass : Bytes | String, key_size, *, salt : Bytes | String | Nil = nil) : {SecureBuffer, Params}
pw = Key.new
salt ||= pw.random_salt
pw.salt = salt.to_slice
key = create_key! pw, pass.to_slice, key_size
{key, pw.to_params(salt: pw.salt, key_size: key_size, tcost: @tcost)}
end
def create_kdf(pass, *, salt : Bytes | String | Nil = nil) : {Kdf, Params}
key, params = create_key pass, Kdf::KEY_SIZE, salt: salt
{Kdf.new(key), params}
end
protected def create_key!(pw, pass : Bytes, key_size : Int32) : SecureBuffer
pw.ops = OPSLIMIT_MIN
mem = MEMLIMIT_MIN
key = SecureBuffer.new key_size
nsamples = 10
samples = nsamples.times.map do
ts = time_derive_key key, pw, pass
end.to_a
mean = samples.sum / nsamples
return key.readonly if mean.to_f >= @tcost
# initial sample to avoid overshooting on busy systems
# round to nearest pow2 / 3
mult = Math.pw2ceil ((@tcost / 3.0 / mean.to_f).ceil.to_i)
pw.mem = (pw.mem * mult).clamp(@mem_min, @mem_max)
last_mem = pw.mem
while pw.mem != @mem_max
ts = time_derive_key key, pw, pass
# tcost exceeded by mem_min
return key.readonly if ts.to_f >= @tcost * 0.9
# / 3 to keep rounds > 1 mitigating attacks against argon with a low number of rounds
break if ts.to_f >= (@tcost / 3.0) * 0.9
last_mem = pw.mem
# increments of 1K for compatibility with other libraries.
pw.mem = (((pw.mem / 1024).to_f * Math.max(1.1, (@tcost / ts.to_f / 3.0))).ceil.to_u64 * 1024).clamp(@mem_min, @mem_max)
# stopped making progress
break if pw.mem == last_mem
end
last_ops = pw.ops
loop do
ts = time_derive_key key, pw, pass
# 90% is close enough
break if ts.to_f >= @tcost * 0.90
last_ops = pw.ops
pw.ops = (pw.ops.to_f * Math.max(1.1, (@tcost / ts.to_f))).ceil.to_u64
# stopped making progress
break if pw.ops == last_ops
end
key.readonly
end
private def time_derive_key(key : SecureBuffer, pw, pass)
# TODO: switch to CPU time
ts = Time.measure do
pw.derive_key key, pass
end
ts.to_f
end
end

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require "./abstract"
module Sodium::Password
class Hash < Abstract
# Apply the most recent password hashing algorithm against a password.
# Returns a opaque String which includes:
# * the result of a memory-hard, CPU-intensive hash function applied to the password
# * the automatically generated salt used for the previous computation
# * the other parameters required to verify the password, including the algorithm identifier, its version, ops and mem.
def create(pass)
outstr = Bytes.new STR_SIZE
if LibSodium.crypto_pwhash_str(outstr, pass, pass.bytesize, @ops, @mem) != 0
raise Sodium::Error.new("crypto_pwhash_str")
end
outstr
end
# Verify a password against a stored String.
# raises PasswordVerifyError on failure.
def verify(str, pass)
# BUG: verify str length
r = LibSodium.crypto_pwhash_str_verify(str, pass, pass.bytesize)
raise Error::Verify.new if r != 0
self
end
# Check if a password verification string str matches the parameters ops and mem, and the current default algorithm.
def needs_rehash?(str) : Bool
# BUG: verify str length
case LibSodium.crypto_pwhash_str_needs_rehash(str, @ops, @mem)
when 0
false
when 1
true
else
raise Sodium::Error.new("crypto_pwhash_str_needs_rehash")
end
end
end
end

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require "./abstract"
require "./mode"
require "../kdf"
module Sodium::Password
# See `Sodium::Password::Key::Create`
#
# TODO: Usage example using the same params with multiple passwords.
class Key < Abstract
# Used by and must be set before calling #derive_key
property mode : Mode = Mode.default
property salt : Bytes?
# Must set a mode before calling.
def derive_key(pass : Bytes | String, key_bytes : Int32, *, salt : String | Bytes | Nil = nil) : SecureBuffer
key = SecureBuffer.new key_bytes
derive_key key, pass, salt: salt
key.readonly
end
def derive_kdf(pass, *, salt = nil) : Kdf
key = derive_key pass, Kdf::KEY_SIZE, salt: salt
Kdf.new key
end
# :nodoc:
def derive_key(key : SecureBuffer, pass : Bytes | String, *, salt : Bytes? = nil) : Nil
m = mode || raise ArgumentError.new("mode not set")
salt ||= @salt
raise ArgumentError.new("missing salt") unless salt
salt = salt.not_nil!
raise "salt expected #{SALT_SIZE} bytes, got #{salt.bytesize} " if salt.bytesize != SALT_SIZE
if LibSodium.crypto_pwhash(key.to_slice, key.bytesize, pass.to_slice, pass.bytesize, salt.to_slice, @ops, @mem, m) != 0
raise Sodium::Error.new("crypto_pwhash")
end
end
def to_params(*, salt = nil, key_size = nil, tcost : Float64? = nil)
Params.new @mode, @ops, @mem, salt: salt, key_size: key_size, tcost: tcost
end
end
end

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require "../lib_sodium"
enum Sodium::Password::Mode
# Use the most recent algorithm Argon2id13 for new applications.
Argon2i13 = 1
Argon2id13 = 2
# The currently recommended algorithm, which can change from one version of libsodium to another.
def self.default
self.new LibSodium.crypto_pwhash_alg_default
end
end

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# Contains the params necessary for #derive_key.
class Sodium::Password::Params
property mode : Mode
property ops : UInt64
property mem : UInt64
property salt : Bytes?
property key_size : Int32?
property tcost : Float64?
property auth : Bytes?
def initialize(@mode, @ops, @mem, @salt = nil, @key_size = nil, @tcost = nil, @auth = nil)
end
def to_h
hash = ::Hash(String, Int32 | UInt64 | String | Bytes | Float64).new initial_capacity: 5
hash["ops"] = @ops
hash["mem"] = @mem
if m = @mode
hash["mode"] = m.to_s
end
if s = @salt
hash["salt"] = s
end
if tc = @tcost
hash["tcost"] = tc
end
if ks = @key_size
hash["key_size"] = ks
end
if au = @auth
hash["auth"] = au
end
hash
end
def self.from_h(hash)
self.new Pwhash::Mode.parse(hash["mode"]), hash["ops"], hash["mem"], hash["tcost"]?, hash["salt"]?
end
end

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require "./lib_sodium"
require "./secure_buffer"
module Sodium
# [Argon2 Password Hashing](https://libsodium.gitbook.io/doc/password_hashing/the_argon2i_function)
# * #store #verify #needs_rehash? are used together for password verification.
# * #derive_key is used on it's own to generate password based keys.
#
# **See `examples/pwhash_selector.cr` for help on selecting parameters.**
class Pwhash
class PasswordVerifyError < Sodium::Error
end
OPSLIMIT_MIN = LibSodium.crypto_pwhash_opslimit_min
OPSLIMIT_INTERACTIVE = LibSodium.crypto_pwhash_opslimit_interactive
OPSLIMIT_MODERATE = LibSodium.crypto_pwhash_opslimit_moderate
OPSLIMIT_SENSITIVE = LibSodium.crypto_pwhash_opslimit_sensitive
OPSLIMIT_MAX = LibSodium.crypto_pwhash_opslimit_max
MEMLIMIT_MIN = LibSodium.crypto_pwhash_memlimit_min
MEMLIMIT_INTERACTIVE = LibSodium.crypto_pwhash_memlimit_interactive
# Don't use this. Maximum of the library which is more ram than any computer.
MEMLIMIT_MAX = LibSodium.crypto_pwhash_memlimit_max
SALT_SIZE = LibSodium.crypto_pwhash_saltbytes
STR_SIZE = LibSodium.crypto_pwhash_strbytes
# Use the most recent algorithm Argon2id13 for new applications.
enum Mode
Argon2i13 = 1
Argon2id13 = 2
# The currently recommended algorithm, which can change from one version of libsodium to another.
def self.default
Mode.new LibSodium.crypto_pwhash_alg_default
end
end
property opslimit = OPSLIMIT_INTERACTIVE
# Specified in bytes.
property memlimit = MEMLIMIT_INTERACTIVE
# Only used by create_key.
# Specified in seconds.
property tcost = 0.1
# Only used by create_key.
property memlimit_min = MEMLIMIT_MIN
# Only used by create_key.
# Specified in bytes.
# defaults to 256M.
# TODO: defaults to 1/4 RAM (not swap).
property memlimit_max : UInt64 = 256_u64 * 1024 * 1024
# Used by and must be set before calling #derive_key
property mode : Mode?
# Apply the most recent password hashing algorithm against a password.
# Returns a opaque String which includes:
# * the result of a memory-hard, CPU-intensive hash function applied to the password
# * the automatically generated salt used for the previous computation
# * the other parameters required to verify the password, including the algorithm identifier, its version, opslimit and memlimit.
def create(pass)
outstr = Bytes.new STR_SIZE
if LibSodium.crypto_pwhash_str(outstr, pass, pass.bytesize, @opslimit, @memlimit) != 0
raise Sodium::Error.new("crypto_pwhash_str")
end
outstr
end
# Verify a password against a stored String.
# raises PasswordVerifyError on failure.
def verify(str, pass)
# BUG: verify str length
case LibSodium.crypto_pwhash_str_verify(str, pass, pass.bytesize)
when 0
# Passed
else
raise PasswordVerifyError.new
end
self
end
# Check if a password verification string str matches the parameters opslimit and memlimit, and the current default algorithm.
def needs_rehash?(str) : Bool
# BUG: verify str length
case LibSodium.crypto_pwhash_str_needs_rehash(str, @opslimit, @memlimit)
when 0
false
when 1
true
else
raise Sodium::Error.new("crypto_pwhash_str_needs_rehash")
end
end
# def set_params(secs, *, min_mem = MEMLIMIT_MIN, max_mem = 256*1024*1024)
# end
def derive_key(salt, pass, key_bytes)
derive_key salt.to_slice, pass.to_slice, key_bytes
end
# Returns a consistent key based on [salt, pass, key_bytes, mode, ops_limit, mem_limit] in a SecureBuffer
#
# Must set a mode before calling.
def derive_key(salt : Bytes | String, pass : Bytes | String, key_bytes) : SecureBuffer
raise "salt expected #{SALT_SIZE} bytes, got #{salt.bytesize} " if salt.bytesize != SALT_SIZE
m = mode || raise ArgumentError.new("mode not set")
key = SecureBuffer.new key_bytes
derive_key key, m, salt, pass
key.readonly
end
private def derive_key(key : SecureBuffer, m : Mode, salt : Bytes | String, pass : Bytes | String) : Nil
if LibSodium.crypto_pwhash(key.to_slice, key.bytesize, pass.to_slice, pass.bytesize, salt.to_slice, @opslimit, @memlimit, m) != 0
raise Sodium::Error.new("crypto_pwhash")
end
end
private def time_derive_key(key, m, salt, pass)
# TODO: switch to CPU time
ts = Time.measure do
derive_key key, m, salt, pass
end
ts
end
# Returns a consistent key based on [salt, pass, key_bytes, mode] in a SecureBuffer **and** a new `Pwhash` with new params.
# Params on the new `Pwhash` are set to run in approximately `tcost` seconds.
# Make sure you store `mode`, `opslimit` and `memlimit` for later use with #derive_key.
# `Mode` has #to_s and #from_s for use with configuration files or databases.
def create_key(salt : Bytes | String, pass : Bytes | String, key_bytes) : {SecureBuffer, self}
pw = dup
key = pw.create_key! salt, pass, key_bytes
{key, pw}
end
# :nodoc:
def create_key!(salt : Bytes | String, pass : Bytes | String, key_bytes) : SecureBuffer
m = self.mode ||= Mode.default
@opslimit = OPSLIMIT_MIN
@memlimit = MEMLIMIT_MIN
key = SecureBuffer.new key_bytes
nsamples = 10
samples = nsamples.times.map do
ts = time_derive_key key, m, salt, pass
end.to_a
mean = samples.sum / nsamples
return key.readonly if mean.to_f >= @tcost
# initial sample to avoid overshooting on busy systems
# round to nearest pow2 / 3
mult = Math.pw2ceil ((@tcost / 3.0 / mean.to_f).ceil.to_i)
@memlimit = (@memlimit * mult).clamp(@memlimit_min, @memlimit_max)
last_memlimit = @memlimit
while @memlimit != @memlimit_max
ts = time_derive_key key, m, salt, pass
# tcost exceeded by memlimit_min
return key.readonly if ts.to_f >= @tcost * 0.9
# / 3 to keep rounds > 1 mitigating attacks against argon with a low number of rounds
break if ts.to_f >= (@tcost / 3.0) * 0.9
last_memlimit = @memlimit
# increments of 1K for compatibility with other libraries.
@memlimit = (((@memlimit / 1024).to_f * Math.max(1.1, (@tcost / ts.to_f / 3.0))).ceil.to_u64 * 1024).clamp(@memlimit_min, @memlimit_max)
# stopped making progress
break if @memlimit == last_memlimit
end
last_opslimit = @opslimit
loop do
ts = time_derive_key key, m, salt, pass
# 90% is close enough
break if ts.to_f >= @tcost * 0.90
last_opslimit = @opslimit
@opslimit = (@opslimit.to_f * Math.max(1.1, (@tcost / ts.to_f))).ceil.to_u64
# stopped making progress
break if @opslimit == last_opslimit
end
key.readonly
end
# Creates a key using create_key and returns `{ KDF.new(key), Pwhash }`
# See #create_key for more details.
def create_kdf(salt, pass, key_bytes) : {Kdf, self}
key, pwhash = create_key salt.to_slice, pass.to_slice, key_bytes
{Kdf.new(key), pwhash}
end
# Derives a key using derive_key and returns `KDF.new(key)`
def derive_kdf(salt, pass, key_bytes)
key = derive_key salt.to_slice, pass.to_slice, key_bytes
Kdf.new key
end
# Returns a random salt for use with #derive_key
def random_salt
Random::Secure.random_bytes SALT_SIZE
end
end
end