CODEWITHSUNDEEP
java
tian-xiaocai
tian-xiaocai

Reputation: 31

How to use RSA_PKCS1_OAEP_PADDING encrypt in Java

In Java, how to use RSA_PKCS1_OAEP_PADDING to encrypt? When I use this below, it shows

javax.crypto.NoSuchPaddingException:RSA/ECB/OAEPPadding unavailable with RSA

cipher = Cipher.getInstance("RSA/ECB/OAEPPadding", provider);

Can you tell me the correct answer?

Upvotes: 1

Views: 2453

Answers (2)

Kebab Krabby
Kebab Krabby

Reputation: 1699

Bit late to the party but this could help:

private const val ALGORITHM = "RSA"
private const val CIPHER = "RSA/ECB/OAEPWithSHA-256AndMGF1Padding"
private const val SHA_256 = "SHA-256"
private const val MGF1 = "MGF1"
private const val PUBLIC_KEY_RSA_PKCS1_OAEP_PADDING = "FpMUwRxHsWFXlnAE1iSFC4q3d0bI...." // your public key

val keyBytes: ByteArray = Base64.decode(PUBLIC_KEY_RSA_PKCS1_OAEP_PADDING.replace("\n", "").replace("\r", ""), Base64.NO_WRAP)  
val keyFactory = KeyFactory.getInstance(ALGORITHM)
val publicKeySpec = X509EncodedKeySpec(keyBytes)
val publicKey = keyFactory.generatePublic(publicKeySpec)

val cipher = Cipher.getInstance(CIPHER)
val oaepParams = OAEPParameterSpec(SHA_256, MGF1, MGF1ParameterSpec.SHA256, PSource.PSpecified.DEFAULT)
cipher.init(Cipher.ENCRYPT_MODE, publicKey, oaepParams)

val encryptedData = cipher.doFinal(dataToEncrypt.toByteArray(Charsets.UTF_8))

val encryptedStringInUtf8 = Base64.encode(encryptedData, Base64.NO_WRAP).toUtf8String()

utf8 helper method:

fun ByteArray.toUtf8String() = toString(UTF_8)

Upvotes: 3

erickson
erickson

Reputation: 269627

Try without specifying a provider, that is:

cipher = Cipher.getInstance("RSA/ECB/OAEPPadding");

If you want to use a specific provider, provide more information about which provider you are using, and what evidence you have that the provider supports OAEP padding.

There is meta-data in the provider itself about the services it provides and their details. We can look into that further if needed, but I think the answer here is simply that this provider doesn't make any provision for OAEP.

Upvotes: 1

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