使用RSA解密时出现BadPaddingException

Question

我在尝试解密某些加密数据时遇到BadPaddingException。当数据被加密时(在转换到base64之前(，字节数组是128字节，当从base64转换加密数据时，字节数组也是128字节，所以这部分看起来是正确的。

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 =
"MIICeAIBADANBgkqhkiG9w0BAQEFAASCAmIwggJeAgEAAoGBAPcPm8Jx3W7ZPulQn" +
"..." +
"g4Ba8WBhgQ7D/tCAww4l8VhyGJm5/88O+xq2Kr69RIHcWTvhck76n08CQQDSPVB6n" +
"+MhX/txtOjY8Y+FOFXOeb0EIMhaMQR02+3+wIbN/IMJUyz2Eq/mDX8oX8BwMGlahn" +
"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
}

以下是完整的异常日志：

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$1.invokeSuspend(AccountsServlet.kt:31)
at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
at kotlinx.coroutines.DispatchedTask.run(Dispatched.kt:241)
at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:594)
at kotlinx.coroutines.scheduling.CoroutineScheduler.access$runSafely(CoroutineScheduler.kt:60)
at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:740)

Answer 1

Encrpyt和Decrypt:中的填充参数不匹配

在encryptWithRSA()方法中，它是：

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

在decryptWithRSA()方法中，它是：

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

为加密和解密选择一种类型的填充，它应该可以工作。

注意：正如Dave所指出的，没有pad是一个严重的安全缺陷，所以最好将其包含在密码中。

Answer 2

我用它来处理这个：

fun encryptWithRSA(dataToEncrypt: String): String {
// See: https://stackoverflow.com/questions/5789685/rsa-encryption-with-given-public-key-in-java
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 =
"MIICeAIBADANBgkqhkiG9w0BAQEFAASCAmIwggJeAgEAAoGBAPcPm8Jx3W7ZPulQn" +
"..." +
"+MhX/txtOjY8Y+FOFXOeb0EIMhaMQR02+3+wIbN/IMJUyz2Eq/mDX8oX8BwMGlahn" +
"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，当加密/解密时，您必须使用相同的初始化：

val keyFactory = KeyFactory.getInstance("RSA")