关于Kotlin中的椭圆曲线加密(Elliptic Curve Encryption)是否有相关信息?
用于生成密钥对和加密、解密消息。
这个主题的信息非常少或没有。
我想要实现ECC P-521椭圆曲线,例如。
也许可以在Kotlin中使用Java版本吗?
我们如何实现呢?
关于Kotlin中的椭圆曲线加密(Elliptic Curve Encryption)是否有相关信息?
用于生成密钥对和加密、解密消息。
这个主题的信息非常少或没有。
我想要实现ECC P-521椭圆曲线,例如。
也许可以在Kotlin中使用Java版本吗?
我们如何实现呢?
implementation 'org.bouncycastle:bcprov-jdk15to18:1.67'
// Add BouncyCastle
Security.removeProvider("BC")
Security.addProvider(BouncyCastleProvider())
// Key Pair Generation
val keyPairGenerator = KeyPairGenerator.getInstance("ECDH")
keyPairGenerator.initialize(ECGenParameterSpec("secp521r1"))
val keyPair = keyPairGenerator.generateKeyPair()
// Encryption
val plaintext = "The quick brown fox jumps over the lazy dog".toByteArray(StandardCharsets.UTF_8)
val cipherEnc = Cipher.getInstance("ECIES")
cipherEnc.init(Cipher.ENCRYPT_MODE, keyPair.public) // In practice, the public key of the recipient side is used
val ciphertext = cipherEnc.doFinal(plaintext)
// Decryption
val cipherDec = Cipher.getInstance("ECIES")
cipherDec.init(Cipher.DECRYPT_MODE, keyPair.private)
val decrypted = cipherDec.doFinal(ciphertext)
println(String(decrypted, StandardCharsets.UTF_8))
已使用API级别28 / Android 9 Pie进行测试。
// Generate Keys
val keyPairA = generateKeyPair()
val keyPairB = generateKeyPair()
// Generate shared secrets
val sharedSecretA = getSharedSecret(keyPairA.private, keyPairB.public)
val sharedSecretB = getSharedSecret(keyPairB.private, keyPairA.public)
// Generate AES-keys
val aesKeyA = getAESKey(sharedSecretA)
val aesKeyB = getAESKey(sharedSecretB)
// Encryption (WLOG by A)
val plaintextA = "The quick brown fox jumps over the lazy dog".toByteArray(StandardCharsets.UTF_8)
val ciphertextA = encrypt(aesKeyA, plaintextA)
// Decryption (WLOG by B)
val plaintextB = decrypt(aesKeyB, ciphertextA)
println(String(plaintextB, StandardCharsets.UTF_8))
使用:
private fun generateKeyPair(): KeyPair {
val keyPairGenerator = KeyPairGenerator.getInstance("EC")
keyPairGenerator.initialize(ECGenParameterSpec("secp521r1"))
return keyPairGenerator.generateKeyPair()
}
private fun getSharedSecret(privateKey: PrivateKey, publicKey: PublicKey): ByteArray {
val keyAgreement = KeyAgreement.getInstance("ECDH")
keyAgreement.init(privateKey)
keyAgreement.doPhase(publicKey, true)
return keyAgreement.generateSecret()
}
private fun getAESKey(sharedSecret: ByteArray): ByteArray {
val digest = MessageDigest.getInstance("SHA-512")
return digest.digest(sharedSecret).copyOfRange(0, 32)
}
private fun encrypt(aesKey: ByteArray, plaintext: ByteArray): ByteArray {
val secretKeySpec = SecretKeySpec(aesKey, "AES")
val iv = ByteArray(12) // Create random IV, 12 bytes for GCM
SecureRandom().nextBytes(iv)
val gCMParameterSpec = GCMParameterSpec(128, iv)
val cipher = Cipher.getInstance("AES/GCM/NoPadding")
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, gCMParameterSpec)
val ciphertext = cipher.doFinal(plaintext)
val ivCiphertext = ByteArray(iv.size + ciphertext.size) // Concatenate IV and ciphertext (the MAC is implicitly appended to the ciphertext)
System.arraycopy(iv, 0, ivCiphertext, 0, iv.size)
System.arraycopy(ciphertext, 0, ivCiphertext, iv.size, ciphertext.size)
return ivCiphertext
}
private fun decrypt(aesKey: ByteArray, ivCiphertext: ByteArray): ByteArray {
val secretKeySpec = SecretKeySpec(aesKey, "AES")
val iv = ivCiphertext.copyOfRange(0, 12) // Separate IV
val ciphertext = ivCiphertext.copyOfRange(12, ivCiphertext.size) // Separate ciphertext (the MAC is implicitly separated from the ciphertext)
val gCMParameterSpec = GCMParameterSpec(128, iv)
val cipher = Cipher.getInstance("AES/GCM/NoPadding")
cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, gCMParameterSpec)
return cipher.doFinal(ciphertext)
}
再次使用 API Level 28 / Android 9 Pie 进行测试。