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[Crypto] Randomness improvements

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Specifically:

  - Now use blocking `getInstanceStrong` when available (Java 8+)
  - Now auto reseed prng after every ~10k calls (slower but safer)
  - [BREAKING] Support arbitrary random-bytes fn
  - Added new `rand-x` fns (double, long, bool, gauss)
This commit is contained in:
Peter Taoussanis 2018-09-15 10:37:39 +02:00
parent 7fa1d3686c
commit 82bb2f0104
2 changed files with 41 additions and 16 deletions
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43
src/taoensso/nippy/crypto.clj
View file

@ -10,9 +10,23 @@
;;;; Randomness
(do
(def ^:private prng* (enc/thread-local-proxy (java.security.SecureRandom/getInstance "SHA1PRNG")))
(defn prng ^java.security.SecureRandom [] (.get ^ThreadLocal prng*))
(defn rand-bytes [size] (let [ba (byte-array size)] (.nextBytes (prng) ba) ba)))
(enc/compile-if (fn [] (java.security.SecureRandom/getInstanceStrong)) ; Java 8+, blocking
(def ^:private prng* (enc/thread-local-proxy (java.security.SecureRandom/getInstanceStrong)))
(def ^:private prng* (enc/thread-local-proxy (java.security.SecureRandom/getInstance "SHA1PRNG"))))
(defn prng
"Favours security over performance. May block while waiting on system entropy!"
^java.security.SecureRandom []
(let [rng ^java.security.SecureRandom (.get ^ThreadLocal prng*)]
;; For additional security, occasionally supplement current seed, Ref. https://goo.gl/MPM91w:
(when (< (.nextDouble rng) 1.0E-4) (.setSeed rng (.generateSeed rng 8)))
rng))
(defn rand-bytes "Uses `prng`" ^bytes [size] (let [ba (byte-array size)] (.nextBytes (prng) ba) ba))
(defn rand-double "Uses `prng`" ^double [] (.nextDouble (prng)))
(defn rand-long "Uses `prng`" ^long [] (.nextLong (prng)))
(defn rand-gauss "Uses `prng`" ^double [] (.nextGaussian (prng)))
(defn rand-bool "Uses `prng`" [] (.nextBoolean (prng))))
(comment (seq (rand-bytes 16)))
@ -76,9 +90,12 @@
;; Output bytes: [ <iv> <?salt> <encrypted>]
;; Could also do: [<iv-len> <iv> <salt-len> <?salt> <encrypted>]
(defn encrypt [cipher-kit ?salt-ba key-ba ba]
(defn encrypt
[{:keys [cipher-kit ?salt-ba key-ba ba rand-bytes-fn]
:or {cipher-kit cipher-kit-aes-gcm
rand-bytes-fn rand-bytes}}]
(let [iv-size (long (get-iv-size cipher-kit))
iv-ba (rand-bytes iv-size)
iv-ba (rand-bytes-fn iv-size)
prefix-ba (if ?salt-ba (enc/ba-concat iv-ba ?salt-ba) iv-ba)
key-spec (get-key-spec cipher-kit key-ba)
param-spec (get-param-spec cipher-kit iv-ba)
@ -87,9 +104,11 @@
(.init cipher javax.crypto.Cipher/ENCRYPT_MODE key-spec param-spec)
(enc/ba-concat prefix-ba (.doFinal cipher ba))))
(comment (encrypt cipher-kit-aes-gcm nil (take-ba 16 (sha512-ba nil "pwd")) (utf8->ba "data")))
(comment (encrypt {:?salt-ba nil :key-ba (take-ba 16 (sha512-ba nil "pwd")) :ba (utf8->ba "data")}))
(defn decrypt [cipher-kit salt-size salt->key-fn ba]
(defn decrypt
[{:keys [cipher-kit salt-size salt->key-fn ba]
:or {cipher-kit cipher-kit-aes-gcm}}]
(let [salt-size (long salt-size)
iv-size (long (get-iv-size cipher-kit))
prefix-size (+ iv-size salt-size)
@ -111,8 +130,8 @@
(defn sha512-16 [?salt-ba pwd] (take-ba 16 (sha512-ba ?salt-ba pwd)))
(defn roundtrip [kit ?salt-ba key-ba key-fn]
(let [salt-size (count ?salt-ba)
encr (encrypt kit ?salt-ba key-ba (utf8->ba "data"))
decr (decrypt kit salt-size key-fn encr)]
encr (encrypt {:cipher-kit kit :?salt-ba ?salt-ba :key-ba key-ba :ba (utf8->ba "data")})
decr (decrypt {:cipher-kit kit :salt-size salt-size :salt->key-fn key-fn :ba encr})]
(String. ^bytes decr "UTF-8")))
[(let [s (rand-bytes 16)] (roundtrip cipher-kit-aes-gcm s (sha512-16 s "pwd") #(sha512-16 % "pwd")))
@ -121,7 +140,7 @@
(let [s nil] (roundtrip cipher-kit-aes-cbc s (sha512-16 s "pwd") #(sha512-16 % "pwd")))])
(enc/qb 10
(roundtrip "foo" {})
(roundtrip "foo" {:cipher-kit cipher-kit-aes-cbc}))
;; [2348.05 2332.25]
(let [s (rand-bytes 16)]
(roundtrip cipher-kit-aes-gcm s (sha512-16 s "pwd") #(sha512-16 % "pwd"))))
;; 2394.89
)

14
src/taoensso/nippy/encryption.clj
View file

@ -41,8 +41,11 @@
(salted-key-fn salt-ba pwd)
(cached-key-fn nil pwd)))]
(crypto/encrypt crypto/cipher-kit-aes-cbc
?salt-ba key-ba ba)))
(crypto/encrypt
{:cipher-kit crypto/cipher-kit-aes-cbc
:?salt-ba ?salt-ba
:key-ba key-ba
:ba ba})))
(decrypt [_ typed-pwd ba]
(let [[type pwd] (destructure-typed-pwd typed-pwd)
@ -52,8 +55,11 @@
#(salted-key-fn % pwd)
#(cached-key-fn % pwd))]
(crypto/decrypt crypto/cipher-kit-aes-cbc
(if salt? 16 0) salt->key-fn ba))))
(crypto/decrypt
{:cipher-kit crypto/cipher-kit-aes-cbc
:salt-size (if salt? 16 0)
:salt->key-fn salt->key-fn
:ba ba}))))
(def aes128-encryptor
"Default 128bit AES encryptor with many-round SHA-512 key-gen.