使用 RSA 解密时出现 BadPaddingException

Question

我在尝试解密某些加密数据时收到 BadPaddingException。数据加密时字节数组是128字节（在转换为base64之前），并且从base64转换加密数据时也是128字节，所以这部分似乎是正确的。

fun encryptWithRSA(dataToEncrypt: String): String {

    val modulus = BigInteger("F70F9BC271DD6ED93EE9...F29901", 16)
    val pubExp = BigInteger("010001", 16)

    val keyFactory = KeyFactory.getInstance("RSA")
    val pubKeySpec = RSAPublicKeySpec(modulus, pubExp)
    val key: RSAPublicKey = keyFactory.generatePublic(pubKeySpec) as RSAPublicKey

    val cipher = Cipher.getInstance("RSA/ECB/NoPadding")
    cipher.init(Cipher.ENCRYPT_MODE, key)

    val encryptedBytes = cipher.doFinal(dataToEncrypt.toByteArray())
    val encryptedData  = Base64.getEncoder().encodeToString(encryptedBytes)

    return encryptedData
}

fun decryptWithRSA(dataToDecrypt: String): String {

    val PRIVATE_RSA_KEY_PKCS8 =
            "MIICeAIBADANBgkqhkiG9w0BAQEFAASCAmIwggJeAgEAAoGBAPcPm8Jx3W7ZPulQ\n" +
            "..." +
            "g4Ba8WBhgQ7D/tCAww4l8VhyGJm5/88O+xq2Kr69RIHcWTvhck76n08CQQDSPVB6\n" +
            "+MhX/txtOjY8Y+FOFXOeb0EIMhaMQR02+3+wIbN/IMJUyz2Eq/mDX8oX8BwMGlah\n" +
            "WSWouLwHaZFcDn7Q"


    val keySpec = PKCS8EncodedKeySpec(parseBase64Binary(PRIVATE_RSA_KEY_PKCS8))

    val keyFactory = KeyFactory.getInstance("RSA")
    val privateKey = keyFactory.generatePrivate(keySpec)
    val cipher = Cipher.getInstance("RSA/ECB/OAEPWithSHA1AndMGF1Padding")
    cipher.init(Cipher.DECRYPT_MODE, privateKey)
    val bytes = Base64.getDecoder().decode(dataToDecrypt)
    val decryptedBytes = cipher.doFinal(bytes)
    val decryptedData  = Base64.getEncoder().encodeToString(decryptedBytes)

    return decryptedData
}

这是完整的异常日志：

javax.crypto.BadPaddingException: Decryption error
    at sun.security.rsa.RSAPadding.unpadOAEP(RSAPadding.java:502)
    at sun.security.rsa.RSAPadding.unpad(RSAPadding.java:296)
    at com.sun.crypto.provider.RSACipher.doFinal(RSACipher.java:363)
    at com.sun.crypto.provider.RSACipher.engineDoFinal(RSACipher.java:389)
    at javax.crypto.Cipher.doFinal(Cipher.java:2164)
    at dev.wirespec.security.Encryption.decryptWithRSA(Encryption.kt:162)
    at dev.wirespec.services.accounts.AccountsServlet$doGet.invokeSuspend(AccountsServlet.kt:31)
    at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
    at kotlinx.coroutines.DispatchedTask.run(Dispatched.kt:241)
    at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:594)
    at kotlinx.coroutines.scheduling.CoroutineScheduler.access$runSafely(CoroutineScheduler.kt:60)
    at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:740)

Answer 1

加密和解密中的填充参数不匹配：

在encryptWithRSA()方法中是：

val cipher = Cipher.getInstance("RSA/ECB/NoPadding")

在decryptWithRSA()方法中是：

val cipher = Cipher.getInstance("RSA/ECB/OAEPWithSHA1AndMGF1Padding")

选择一种padding进行加解密，应该可以。

注意：正如 Dave 所指出的，没有 pad 是一个严重的安全漏洞，因此最好将它包含在您的密码中。

Answer 2

我得到它来处理这个：

fun encryptWithRSA(dataToEncrypt: String): String {
    // See: 

    val modulus = BigInteger("F70F9B...0F29901", 16)
    val pubExp = BigInteger("010001", 16)

    val keyFactory = KeyFactory.getInstance("RSA")
    val pubKeySpec = RSAPublicKeySpec(modulus, pubExp)
    val key: RSAPublicKey = keyFactory.generatePublic(pubKeySpec) as RSAPublicKey

    val cipher = Cipher.getInstance("RSA")
    cipher.init(Cipher.ENCRYPT_MODE, key)

    val encryptedBytes = cipher.doFinal(dataToEncrypt.toByteArray())
    val encryptedData  = Base64.getEncoder().encodeToString(encryptedBytes)

    return encryptedData
}


fun decryptWithRSA(dataToDecrypt: String): String {

    val PRIVATE_RSA_KEY_PKCS8 =
            "MIICeAIBADANBgkqhkiG9w0BAQEFAASCAmIwggJeAgEAAoGBAPcPm8Jx3W7ZPulQ\n" +
            "..." +
            "+MhX/txtOjY8Y+FOFXOeb0EIMhaMQR02+3+wIbN/IMJUyz2Eq/mDX8oX8BwMGlah\n" +
            "WSWouLwHaZFcDn7Q"

    val keySpec = PKCS8EncodedKeySpec(parseBase64Binary(PRIVATE_RSA_KEY_PKCS8))

    val keyFactory = KeyFactory.getInstance("RSA")
    val privateKey = keyFactory.generatePrivate(keySpec)
    val cipher = Cipher.getInstance("RSA")
    cipher.init(Cipher.DECRYPT_MODE, privateKey)
    val bytes = Base64.getDecoder().decode(dataToDecrypt)
    val decryptedBytes = cipher.doFinal(bytes)
    val d = decryptedBytes.toString(Charsets.UTF_8)
    val decryptedData  = Base64.getEncoder().encodeToString(decryptedBytes)

    return decryptedData
}

这里最重要的是，当encrypting/decrypting时，你必须使用相同的初始化：

val keyFactory = KeyFactory.getInstance("RSA")

使用 RSA 解密时出现 BadPaddingException

BadPaddingException when decrypting using RSA

encryption

cryptography

rsa

kotlin