KyberKotlin v0.4.5

* Zero fill sensitive data to improve security.
ronhombre · Feb 10, 2024 · 5356baf · 5356baf
1 parent 04bdb8e
commit 5356baf
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Showing 6 changed files with 33 additions and 9 deletions.
diff --git a/README.md b/README.md
@@ -34,9 +34,9 @@ At the 1.0.0 release, developers should be able to use this dependency if they w
 
 | Variant | Generation              | Encapsulation           | Decapsulation           |
 |---------|-------------------------|-------------------------|-------------------------|
-| 512     | 5975.0     (39% Faster) | 5643.5625  (58% Faster) | 5705.3125  (74% Faster) |
-| 768     | 10271.125  (32% Faster) | 10455.9375 (44% Faster) | 10681.1875 (58% Faster) |
-| 1024    | 16849.625  (26% Faster) | 17178.4375 (35% Faster) | 17501.5    (49% Faster) |
+| 512     | 6218.25    (34% Faster) | 5757.8125  (55% Faster) | 5736.4375  (73% Faster) |
+| 768     | 10220.375  (33% Faster) | 10442.75   (44% Faster) | 10603.75   (59% Faster) |
+| 1024    | 16700.1875 (27% Faster) | 17075.6875 (36% Faster) | 17346.6875 (50% Faster) |
 | ML-KEM  | (in ms)                 | (in ms)                 | (in ms)                 |
 
 JVM: Coretto 1.8, Count: 10000, Iterations: 5 (Average), Relative to 'standard' branch.
@@ -59,7 +59,7 @@ This master branch is faster than the standard branch due to optimizations.
 
 ```Kotlin
 dependencies {
-    implementation("asia.hombre:kyber:0.4.4")
+    implementation("asia.hombre:kyber:0.4.5")
 }
 ```
 

diff --git a/build.gradle.kts b/build.gradle.kts
@@ -12,7 +12,7 @@ plugins {
 }
 
 group = "asia.hombre.kyber" //The value after the last '.' is considered the maven name i.e. asia.hombre:kyber:+
-version = "0.4.4"
+version = "0.4.5"
 
 val projectName = project.group.toString().split(".").last() //Grab maven name
 val baseProjectName = projectName.plus("-").plus(project.version)

diff --git a/pom.xml b/pom.xml
@@ -39,11 +39,11 @@
 
     <groupId>asia.hombre</groupId>
     <artifactId>kyber</artifactId>
-    <version>0.4.4</version>
+    <version>0.4.5</version>
     <packaging>jar</packaging>
 
     <scm>
-        <tag>v0.4.4</tag>
+        <tag>v0.4.5</tag>
         <connection>scm:git:https://github.com/ronhombre/KyberKotlin.git</connection>
         <url>https://github.com/ronhombre/KyberKotlin.git</url>
     </scm>

diff --git a/src/commonMain/kotlin/asia/hombre/kyber/KyberAgreement.kt b/src/commonMain/kotlin/asia/hombre/kyber/KyberAgreement.kt
@@ -98,12 +98,21 @@ class KyberAgreement(kemKeyPair: KyberKEMKeyPair) {
             coefficients[i] = KyberMath.vectorToVectorAdd(coefficients[i], noiseVector[i])
 
             constantTerm = KyberMath.vectorToVectorAdd(constantTerm, KyberMath.multiplyNTTs(nttKeyVector[i], randomnessVector[i]))
+
+            //Security Features
+            for(j in 0..<parameter.K) matrix[i][j].fill(0, 0, matrix[i][j].lastIndex)
+            noiseVector[i].fill(0, 0, noiseVector[i].lastIndex)
+            nttKeyVector[i].fill(0, 0, nttKeyVector[i].lastIndex)
+            randomnessVector[i].fill(0, 0, randomnessVector[i].lastIndex)
         }
 
         constantTerm = KyberMath.invNTT(constantTerm)
         constantTerm = KyberMath.vectorToVectorAdd(constantTerm, noiseTerm)
         constantTerm = KyberMath.vectorToVectorAdd(constantTerm, muse)
 
+        //Security Feature
+        muse.fill(0, 0, muse.lastIndex)
+
         val encodedCoefficients = ByteArray(KyberConstants.N_BYTES * (parameter.DU * parameter.K))
         val encodedTerms = ByteArray(KyberConstants.N_BYTES * parameter.DV)
 

diff --git a/src/commonMain/kotlin/asia/hombre/kyber/KyberKeyGenerator.kt b/src/commonMain/kotlin/asia/hombre/kyber/KyberKeyGenerator.kt
@@ -61,17 +61,22 @@ class KyberKeyGenerator {
 
                     val seeds = sha3512.digest(byteArray)
 
+                    //Security Features
+                    sha3512.reset()
+                    byteArray.fill(Byte.MIN_VALUE, 0, byteArray.lastIndex)
+
                     val nttSeed = seeds.copyOfRange(0, 32)
                     val cbdSeed = seeds.copyOfRange(32, 64)
 
+                    seeds.fill(0, 0, seeds.lastIndex) //Security Feature
+
                     val matrix = Array(parameter.K) { Array(parameter.K) { ShortArray(KyberConstants.N) } }
                     val secretVector = Array(parameter.K) { ShortArray(KyberConstants.N) }
                     val noiseVector = Array(parameter.K) { ShortArray(KyberConstants.N) }
 
                     for((nonce, i) in (0..<parameter.K).withIndex()) {
-                        for(j in 0..<parameter.K) {
+                        for(j in 0..<parameter.K)
                             matrix[i][j] = KyberMath.sampleNTT(KyberMath.xof(nttSeed, i.toByte(), j.toByte()))
-                        }
 
                         secretVector[i] = KyberMath.samplePolyCBD(
                             parameter.ETA1,
@@ -86,6 +91,8 @@ class KyberKeyGenerator {
                         noiseVector[i] = KyberMath.NTT(noiseVector[i])
                     }
 
+                    cbdSeed.fill(Byte.MIN_VALUE, 0, cbdSeed.lastIndex) //Security Feature
+
                     //Transposed ? Old Kyber v3
                     val systemVector = KyberMath.vectorAddition(
                         KyberMath.nttMatrixToVectorDot(matrix, secretVector, true),
@@ -96,6 +103,10 @@ class KyberKeyGenerator {
                     val decryptionKeyBytes = ByteArray(parameter.DECRYPTION_KEY_LENGTH)
 
                     for(i in 0..<parameter.K) {
+                        //Security Features
+                        for(j in 0..<parameter.K) matrix[i][j].fill(0, 0, matrix[i][j].lastIndex)
+                        noiseVector[i].fill(0, 0, noiseVector[i].lastIndex)
+
                         KyberMath.byteEncode(KyberMath.montVectorToVector(systemVector[i]), 12)
                             .copyInto(encryptionKeyBytes, i * KyberConstants.ENCODE_SIZE)
                         KyberMath.byteEncode(KyberMath.montVectorToVector(secretVector[i]), 12)

diff --git a/src/commonMain/kotlin/asia/hombre/kyber/internal/KyberMath.kt b/src/commonMain/kotlin/asia/hombre/kyber/internal/KyberMath.kt
@@ -149,6 +149,8 @@ internal class KyberMath {
                 i += 3
             }
 
+            bytes.fill(0, 0, bytes.lastIndex) //Security Feature
+
             return nttCoefficients
         }
 
@@ -157,6 +159,8 @@ internal class KyberMath {
             val f = ShortArray(KyberConstants.N)
             val bits = bytesToBits(bytes)
 
+            bytes.fill(0, 0, bytes.lastIndex) //Security Feature
+
             for(i in 0..<KyberConstants.N) {
                 var x = 0
                 var y = 0