We need to take Modulus and exponent from RSA keys. I have created my pubilc key using following methodology. Please let me know how can we take modulus and exponent part from it. I have already read this post.
NSData* tag = [#"com.x.x.x" dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary* attributes =
#{ (id)kSecAttrKeyType: (id)kSecAttrKeyTypeRSA,
(id)kSecAttrKeySizeInBits: #1024,
(id)kSecPrivateKeyAttrs:
#{ (id)kSecAttrIsPermanent: #YES,
(id)kSecAttrApplicationTag: tag,
},
};
CFErrorRef error = NULL;
SecKeyRef privateKey = SecKeyCreateRandomKey((__bridge CFDictionaryRef)attributes,
&error);
if (!privateKey) {
NSError *err = CFBridgingRelease(error);
// Handle the error. . .
}
SecKeyRef publicKey = SecKeyCopyPublicKey(privateKey);
// Now I want modulus and exponent form this publicKey
EDITED :-
I have also send base64 string to server but there we are facing quite a issue to find public key ref from base64 string. if someone has done it in c#, you can also help us with this
c# code snippet
const string pKey = "-----key-----"
byte[] publicKeyBytes = Convert.FromBase64String(pKey);
var stream = new MemoryStream(publicKeyBytes);
Asn1Object asn1Object = Asn1Object.FromStream(stream);
Now we need public key component which we are unable to parse. Any help would be great
On C# you can achieve the encryption using this way,
const string publicKey = "MIGJAoGBAMIt95f4xaP7vYV/+Hdyb4DK0oKvw495PrRYG3nsYgVP7zlBE/rTN6Nmt69W9d0nGefuRlJFIr9TA8vlJmqTus6uXEasBuEjzH7vM7HQeAK6i8qEbVy0T+Uuq+16yy059NL7i/VWljVE6rqTntDUELmbIwNBwj6oBuL1z3SnFoMjAgMBAAE="; //generated on iOS
byte[] publicKeyBytes = Convert.FromBase64String(pKey);
var stream = new MemoryStream(publicKeyBytes);
Asn1Object asn1Object = Asn1Object.FromStream(stream);
Asn1Encodable asn1Sequence = asn1Object;
AlgorithmIdentifier algorithmIdentifier = new
AlgorithmIdentifier(PkcsObjectIdentifiers.IdRsaesOaep);
SubjectPublicKeyInfo subjectPublicKeyInfo = new
SubjectPublicKeyInfo(algorithmIdentifier, asn1Sequence);
AsymmetricKeyParameter asymmetricKeyParameter2 =
PublicKeyFactory.CreateKey(subjectPublicKeyInfo);
RsaKeyParameters rsaKeyParameters =
(RsaKeyParameters)asymmetricKeyParameter2;
RSAParameters rsaParameters = new RSAParameters();
rsaParameters.Modulus = rsaKeyParameters.Modulus.ToByteArrayUnsigned();
rsaParameters.Exponent = rsaKeyParameters.Exponent.ToByteArrayUnsigned();
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
rsa.ImportParameters(rsaParameters);
string test = "John snow is the true king";
byte[] encbyte = rsa.Encrypt(Encoding.UTF8.GetBytes(test), RSAEncryptionPadding.Pkcs1);
string encrt = Convert.ToBase64String(encbyte);
I have been struggling with decrypting some data that is being encrypted on a Unix machine via SSL, I keep getting padding errors, and am unsure what it is that I am missing.
The encrypted file is a simple text file just saying "Hello World".
The encryption command used in unix is:
openssl enc -base64 -aes-256-cbc -k 12345678901234567890123456789012 -in test.txt -out cbc64.txt
I have 2 methods that I am using to decrypt:
private static CipherMode sCipherMode = CipherMode.CBC;
private static PaddingMode sPaddingMode = PaddingMode.PKCS7;
private const int HigKeyLen = 32;
private const int HigKeySiz = 256;
public static string decrypt(string text, //the text to be decrypt
int cipherindex// the strength of the original encryption
)
{
byte[] plainText = null;
try
{
string tempText = Regex.Replace(text, #"\n", "");
//get the cipher strength--from cipherindex
CipherKey Key = CipherKey.getCipherKey(cipherindex);
//build and init the Decryptor
RijndaelManaged rijndaelCipher = new RijndaelManaged();
rijndaelCipher.Mode = sCipherMode;
rijndaelCipher.Padding = sPaddingMode;
rijndaelCipher.KeySize = Key.Size;
rijndaelCipher.BlockSize = Key.Size;
byte[] encryptedData = Convert.FromBase64String(tempText);
byte[] pwdBytes = System.Text.Encoding.UTF8.GetBytes(pass);
byte[] keyBytes = new byte[Key.Len];
int len = pwdBytes.Length;
if (len > keyBytes.Length)
{
len = keyBytes.Length;
}
Array.Copy(pwdBytes, keyBytes, len);
rijndaelCipher.Key = keyBytes;
rijndaelCipher.IV = keyBytes;
ICryptoTransform transform = rijndaelCipher.CreateDecryptor();
plainText = transform.TransformFinalBlock(encryptedData, 0, encryptedData.Length);
}
catch (Exception e)
{
// test code, do nothing
}
return System.Text.Encoding.UTF8.GetString(plainText);
}
This returns the following error: Padding is invalid and cannot be removed.
The second method:
public static string Decryptor(string TextToDecrypt)
{
byte[] EncryptedBytes = Convert.FromBase64String(Regex.Replace(TextToDecrypt, #"\n", ""));
//Setup the AES provider for decrypting.
AesCryptoServiceProvider aesProvider = new AesCryptoServiceProvider();
//aesProvider.Key = System.Text.Encoding.ASCII.GetBytes(strKey);
//aesProvider.IV = System.Text.Encoding.ASCII.GetBytes(strIV);
aesProvider.BlockSize = 128;
aesProvider.KeySize = 256;
//My key and iv that i have used in openssl
aesProvider.Key = System.Text.Encoding.UTF8.GetBytes(pass);
aesProvider.IV = System.Text.Encoding.UTF8.GetBytes(pass);
aesProvider.Padding = PaddingMode.PKCS7;
aesProvider.Mode = CipherMode.CBC;
ICryptoTransform cryptoTransform = aesProvider.CreateDecryptor(aesProvider.Key, aesProvider.IV);
byte[] DecryptedBytes = cryptoTransform.TransformFinalBlock(EncryptedBytes, 0, EncryptedBytes.Length);
return System.Text.Encoding.ASCII.GetString(DecryptedBytes);
}
The second method gives an issue due to the password not being the right length for the blocksize.
What is it that I am doing wrong?
You openssl command is wrong, I assume it should be:
openssl enc -base64 -aes-256-cbc -k 12345678901234567890123456789012 -in test.txt -out cbc64.txt
reading your code I see you made a few wrong assumptions:
You are using the password as a key and as IV (where did you get that?)
Password is not key
you've assumed the output is pure ciphertext
try to add -p parameter to the openssl enc command and it will display as well salt and derived key and iv
So lets fix that:
OpenSSL generates random 8 bytes salt
OpenSSL uses its "magic" function EVP_BytesToKey to derive the key and IV from the passsword and salt, example impl in c#
OpenSSL output looks like: base64(Salted_{salt}{ciphertext})
Hi there i'm using this encryption method to encrypt my json value in .net side
public static string Encrypt256(string text)
{
AesCryptoServiceProvider aes = new AesCryptoServiceProvider();
aes.BlockSize = 128;
aes.KeySize = 256;
aes.IV = Encoding.UTF8.GetBytes(AesIV256);
aes.Key = Encoding.UTF8.GetBytes(AesKey256);
aes.Mode = CipherMode.CBC;
byte[] src = Encoding.Unicode.GetBytes(text);
using (ICryptoTransform encrypt = aes.CreateEncryptor())
{
byte[] dest = encrypt.TransformFinalBlock(src, 0, src.Length);
Debug.WriteLine(Convert.ToBase64String(dest));
return Convert.ToBase64String(dest);
}
}
And im trying to decrypt it in Node Js side
var crypto = require('crypto'),
algorithm = process.env.tombalaCryptoAlgorithm,
password = process.env.tombalaHmacPass,
iv = '!QAZ2WSX#EDC4RFV'
function encrypt(text) {
var cipher = crypto.createCipheriv(algorithm, password, iv)
var encrypted = cipher.update(text, 'utf8', 'base64')
encrypted += cipher.final('base64');
return encrypted;
You are converting your text to be encrypted to Unicode which means UTF-16.
In UTF-16 every character consists of two bytes. If the second byte is not used it is null as you have observed.
I assume you want UTF-8 encoding. Therefore replace the line
byte[] src = Encoding.Unicode.GetBytes(text);
with
byte[] src = Encoding.UTF8.GetBytes(text);
The System.Security.Cryptography does include a DES Decode method, but the Windows.Security.Cryptography Namespace for Windows Phone 8.1 programming doesn't include any method for decoding DES.
I just found a Class, Windows.Security.Cryptography.Core.SymmetricAlgorithmNames.DesCbc,
but I don't have any idea how to decrypt my DES encrypted String. I would appreciate every idea you have in your mind.
I think I've got it.
Code Snippet:
strAsymmetricAlgName = SymmetricAlgorithmNames.DesCbc;
SymmetricKeyAlgorithmProvider objAlgProv = SymmetricKeyAlgorithmProvider.OpenAlgorithm(strAsymmetricAlgName);
CryptographicKey keyPair = objAlgProv.CreateSymmetricKey(CryptographicBuffer.ConvertStringToBinary("xxx", BinaryStringEncoding.Utf8));
IBuffer val = CryptographicEngine.Decrypt(keyPair, CryptographicBuffer.ConvertStringToBinary(encodedData, BinaryStringEncoding.Utf8), null);
byte[] arr = val.ToArray();
string returnValue = System.Text.Encoding.UTF8.GetString(arr, 0, arr.Length);
I currently don't know the initialization vector that's why it is null.
I am still not 100 % sure if that is right.
The DES string is encrypted by a Java programm:
Cipher c = Cipher.getInstance( "DES" );
Key k = new SecretKeySpec( pass.getBytes(), "DES" );
c.init( Cipher.ENCRYPT_MODE, k );
OutputStream cos = new CipherOutputStream( out, c );
cos.write( bytes );
cos.close()
I can't find any Information about the initialization vector.
I just solved my Problem.
String strAsymmetricAlgName = SymmetricAlgorithmNames.DesEcbPkcs7;
SymmetricKeyAlgorithmProvider objAlgProv = SymmetricKeyAlgorithmProvider.OpenAlgorithm(strAsymmetricAlgName);
CryptographicKey keyPair = objAlgProv.CreateSymmetricKey(CryptographicBuffer.ConvertStringToBinary("key", BinaryStringEncoding.Utf8));
IBuffer str = CryptographicBuffer.CreateFromByteArray(encodedDataAsBytes);
IBuffer buf = CryptographicEngine.Decrypt(keyPair, str, null);
byte[] arr = buf.ToArray();
string returnValue = System.Text.Encoding.UTF8.GetString(arr, 0, arr.Length);
I am trying to encrypt strings in .NET by using a RSA algorithm and decrypt the result in Java. At the moment, I have been able to do the opposite (Encrypt in Java, Decrypt in .NET).
Here I have my code that actually works (JAVA encryption):
byte[] modulusBytes = Base64.decode("2rRVVVFJRbH/wAPDtnwZwu+nxU+AZ6uXxh/sW+AMCBogg7vndZsnRiHoLttYYPqOyOhfgaBOQogrIfrKL4lipK4m52SBzw/FfcM9DsKs/rYR83tBLiIAfgdnVjF27tZID+HJMFTiI30mALjr7+tfp+2lIACXA1RIKTk7S9pDmX8=");
byte[] exponentBytes = Base64.decode("AQAB");
BigInteger modulus = new BigInteger(1, modulusBytes );
BigInteger exponent = new BigInteger(1, exponentBytes);
RSAPublicKeySpec rsaPubKey = new RSAPublicKeySpec(modulus, exponent);
KeyFactory fact = KeyFactory.getInstance("RSA");
PublicKey pubKey = fact.generatePublic(rsaPubKey);
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
cipher.init(Cipher.ENCRYPT_MODE, pubKey);
byte[] plainBytes = new String("big kitty dancing").getBytes("UTF-8");
byte[] cipherData = cipher.doFinal( plainBytes );
String encryptedString = Base64.encode(cipherData);
return encryptedString;
And (.NET decryption)
const int PROVIDER_RSA_FULL = 1;
const string CONTAINER_NAME = "Tracker";
CspParameters cspParams;
cspParams = new CspParameters(PROVIDER_RSA_FULL);
cspParams.KeyContainerName = CONTAINER_NAME;
RSACryptoServiceProvider rsa1 = new RSACryptoServiceProvider(cspParams);
rsa1.FromXmlString("<RSAKeyValue><Modulus>2rRVVVFJRbH/wAPDtnwZwu+nxU+AZ6uXxh/sW+AMCBogg7vndZsnRiHoLttYYPqOyOhfgaBOQogrIfrKL4lipK4m52SBzw/FfcM9DsKs/rYR83tBLiIAfgdnVjF27tZID+HJMFTiI30mALjr7+tfp+2lIACXA1RIKTk7S9pDmX8=</Modulus><Exponent>AQAB</Exponent><P>+lXMCEwIN/7+eMpBrq87kQppxu3jJBTwztGTfXNaPUTx+A6uqRwug5oHBbSpYXKNDNCBzVm/0VxB3bo4FJx+ZQ==</P><Q>yasOGaJaE9xlF9T2xRuKeG9ZxCiyjhYaYB/mbtL+SIbtkRLi/AxaU4g2Il/UxhxhSXArKxIzV28zktispPJx1Q==</Q><DP>ueRgQIEFUV+fY979a1RgrVHIPpqEI1URhOMH3Q59oiXCcOumM5njyIHmWQxRAzXnG+7xlKXi1PrnRll0L4oOKQ==</DP><DQ>dfEMNgG1HJhwpxdtmqkYuoakwQvsIRzcIAuIAJh1DoWaupWJGk8/JEstHb1d+t7uJrzrAi2KyT/HscH2diE0YQ==</DQ><InverseQ>YoYF9PF6FiC0YngVeaC/eqt/ea8wMYNN3YO1LuzWpcy2exPRj2U0ZbWMvHXMUb4ea2qmhZGx1QlK4ULAuWKpXQ==</InverseQ><D>g1WAWI4pEK9TA7CA2Yyy/2FzzNiu0uQCuE2TZYRNiomo96KQXpxwqAzZLw+VDXfJMypwDMAVZe/SqzSJnFEtZxjdxaEo3VLcZ1mnbIL0vS7D6iFeYutF9kF231165qGd3k2tgymNMMpY7oYKjS11Y6JqWDU0WE5hjS2X35iG6mE=</D></RSAKeyValue>");
string data2Decrypt = "BaB21vY+RD/jiY3AAsb269fIWTEH38s0xLUfJ7CoVUgaQ6vYzB0tiJ1Ag9HNEdCcuZdGchhqnms8jpsqsHC1iKrz6QCLsgUU7VNWDfQqZYR6Rl/GwR0biK2STnOL+g06f/JUdixHOHOgROify1m8qppYo5plpOVMqYFzEMREMkM=";
byte[] encyrptedBytes = Convert.FromBase64String(data2Decrypt);
byte[] plain = rsa1.Decrypt(encyrptedBytes, false);
string decryptedString = System.Text.Encoding.UTF8.GetString(plain);
Console.WriteLine("SALIDA: " + decryptedString);
Now I want to do the opposite... But I get some errors like (the size of the key should be 128 bytes... etc) How should I do it?
Here I add the current non working code:
.NET
public string Encrypt(string text)
{
const int PROVIDER_RSA_FULL = 1;
const string CONTAINER_NAME = "Tracker";
CspParameters cspParams;
cspParams = new CspParameters(PROVIDER_RSA_FULL);
cspParams.KeyContainerName = CONTAINER_NAME;
RSACryptoServiceProvider rsa1 = new RSACryptoServiceProvider(cspParams);
rsa1.FromXmlString("<RSAKeyValue><Modulus>2rRVVVFJRbH/wAPDtnwZwu+nxU+AZ6uXxh/sW+AMCBogg7vndZsnRiHoLttYYPqOyOhfgaBOQogrIfrKL4lipK4m52SBzw/FfcM9DsKs/rYR83tBLiIAfgdnVjF27tZID+HJMFTiI30mALjr7+tfp+2lIACXA1RIKTk7S9pDmX8=</Modulus><Exponent>AQAB</Exponent><P>92jJJyzFBSx6gL4Y1YpALmc5CNjoE/wETjqb3ci2v0+3rZWvJKmKy1ZEdlXpyuvXVksJ6cMdUpNAkMknUk9pTQ==</P><Q>4kxkABZOXyDLryYGCGY0b8N0FIdu5BTCFDYEdcatxl/f7ZGDS1NgHJpUWxkVXFfHy2Y/GuDOIbpcwlsO739H+w==</Q><DP>5bNFvrdUHF+VRN45VFjNCcgQLeSkY5mBrdfASoNFGA29LM5iE5nNIMfxPCS7sQiRnq6Af6YFHVtVgJchiMvtqQ==</DP><DQ>j+ng1qVY5epnXlWiFIla45C7K6sNfIMvAcdwgq39KWEjeWPGyYqWXtpOtzh2eylf6Bx4GVHKBW0NPJTIJMsfLQ==</DQ><InverseQ>8uu0dfPVDqB2qFM1Vdi8hl+2uZtN7gjT2co1cEWy29HVYBZD0k9KKCf2PbkeuSfpgFpE70wW5Hrp8V7l/SwSOw==</InverseQ><D>MM/c18zroJ2Iqi9s5/asvUBF3pjO3NSEbFjFpP/NT6WdKimvECWPz2xT6NlV0Vc6tQaAAmtn7Bt+HPhfVdrA4/ysYVe3/6TWkPjW+bvAhMWu/ZqISx11/jPYSGD9g3ZXgUiqcQM8UbOjlswoq4fpheEXTB0xdVutDLpO3qgHN6k=</D></RSAKeyValue>");
System.Text.UTF8Encoding encoding = new System.Text.UTF8Encoding();
byte[] textBytes = encoding.GetBytes(text);
byte[] encryptedOutput = rsa1.Encrypt(textBytes, false);
string outputB64 = Convert.ToBase64String(encryptedOutput);
Console.WriteLine(outputB64);
return outputB64;
}
Java
public static String Decrypt(String encodedString) throws IllegalBlockSizeException, UnsupportedEncodingException, InvalidKeyException, NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, BadPaddingException
{
byte[] modulusBytes = Base64.decode("2rRVVVFJRbH/wAPDtnwZwu+nxU+AZ6uXxh/sW+AMCBogg7vndZsnRiHoLttYYPqOyOhfgaBOQogrIfrKL4lipK4m52SBzw/FfcM9DsKs/rYR83tBLiIAfgdnVjF27tZID+HJMFTiI30mALjr7+tfp+2lIACXA1RIKTk7S9pDmX8=");
byte[] exponentBytes = Base64.decode("AQAB");
BigInteger modulus = new BigInteger(1, modulusBytes );
BigInteger exponent = new BigInteger(1, exponentBytes);
RSAPrivateKeySpec rsaPrivKey = new RSAPrivateKeySpec(modulus, exponent);
KeyFactory fact = KeyFactory.getInstance("RSA");
PrivateKey privKey = fact.generatePrivate(rsaPrivKey);
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
cipher.init(Cipher.DECRYPT_MODE, privKey);
byte[] base64String = Base64.decode(encodedString);
byte[] plainBytes = new String(base64String).getBytes("UTF-8");
byte[] cipherData = cipher.doFinal(plainBytes);
System.out.println(cipherData);
return cipherData.toString();
}
The last few lines of your Java decrypt code do not make sense. These lines are:
byte[] base64String = Base64.decode(encodedString);
byte[] plainBytes = new String(base64String).getBytes("UTF-8");
byte[] cipherData = cipher.doFinal(plainBytes);
System.out.println(cipherData);
return cipherData.toString();
You have to reverse the order of the steps you used to encrypt in .NET. First, you should Base64 decode the encoded string to get the cipher bytes. You did that, but you mislabeled the result as base64String. You probably should call this result cipherData. Second, you need to decrypt cipherData to get plain text. Third, you should create a string from plainbytes using the two-arg String constructor with the Charset for the second argument. Here is what the code should look like, or close to it.
byte[] cipherData = Base64.decode(encodedString);
byte[] plainBytes = cipher.doFinal(cipherData);
return new String(plainBytes, "UTF-8");
Finally, in Java every object has a toString() method but it doesn't always do what you want. For arrays the toString() method simply returns a representation of object id for that array, sort of the JVM equivalent of a memory address.
EDIT:
I missed that you are also using the wrong key in your decrypt code. Your are using the RSA public key, but you must instead use the RSA private key.
Here is the answer I couldn't post yesterday, related to the first answer to my post.
Well, I have tested the code and I have some problems. I have tried not to change anything unless it was completely necessary.
First I get an error here:
Cipher rsaCipher = Cipher.getInstance(RSA_ALGORITHM, CRYPTO_PROVIDER);
The "Entrust" crypto provider is not recognized... So I left just the first parameter. Then I get this error:
javax.crypto.BadPaddingException: Data must start with zero
I have tried through a WebService written in .NET which returns always byte arrays. Maybe there is some kind of problem in the translation. I know that I have to use Base64 numbers and (if I don't use AES) I have to break my Strings into pieces with the size of 128 bytes (limited by the RSA key).
I am still working on the problem to realize why I could encrypt in Java and decrypt in .NET but not the opposite.
Thanks again for your help!!
As you requested are hare some code snippets. RSA keys are from x509 certs.
Java RSA/AES:
// symmetric algorithm for data encryption
final String ALGORITHM = "AES";
// Padding for symmetric algorithm
final String PADDING_MODE = "/CBC/PKCS5Padding";
// character encoding
final String CHAR_ENCODING = "UTF-8";
// provider for the crypto
final String CRYPTO_PROVIDER = "Entrust";
// RSA algorithm used to encrypt symmetric key
final String RSA_ALGORITHM = "RSA/ECB/PKCS1Padding";
// symmetric key size (128, 192, 256) if using 192+ you must have the Java
// Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files
// installed
int AES_KEY_SIZE = 256;
private byte[] encryptWithRSA(byte[] aesKey, X509Certificate cert)
throws NoSuchAlgorithmException, NoSuchPaddingException,
InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
// get the public key from the encryption certificate to encrypt with
PublicKey pubKey = cert.getPublicKey();
// get an instance of the RSA Cipher
Cipher rsaCipher = Cipher.getInstance(RSA_ALGORITHM);
// set the cipher to use the public key
rsaCipher.init(Cipher.ENCRYPT_MODE, pubKey);
// encrypt the aesKey
return rsaCipher.doFinal(aesKey);
}
private AESEncryptedContents encryptWithAes(byte[] dataToEncrypt)
throws NoSuchAlgorithmException, NoSuchPaddingException,
InvalidKeyException, IllegalBlockSizeException,
BadPaddingException, NoSuchProviderException {
// get the symmetric key generator
KeyGenerator keyGen = KeyGenerator.getInstance(ALGORITHM);
keyGen.init(AES_KEY_SIZE); // set the key size
// generate the key
SecretKey skey = keyGen.generateKey();
// convert to binary
byte[] rawAesKey = skey.getEncoded();
// initialize the secret key with the appropriate algorithm
SecretKeySpec skeySpec = new SecretKeySpec(rawAesKey, ALGORITHM);
// get an instance of the symmetric cipher
Cipher aesCipher = Cipher.getInstance(ALGORITHM + PADDING_MODE,
CRYPTO_PROVIDER);
// set it to encrypt mode, with the generated key
aesCipher.init(Cipher.ENCRYPT_MODE, skeySpec);
// get the initialization vector being used (to be returned)
byte[] aesIV = aesCipher.getIV();
// encrypt the data
byte[] encryptedData = aesCipher.doFinal(dataToEncrypt);
// package the aes key, IV, and encrypted data and return them
return new AESEncryptedContents(rawAesKey, aesIV, encryptedData);
}
private byte[] decryptWithAES(byte[] aesKey, byte[] aesIV,
byte[] encryptedData) throws NoSuchAlgorithmException,
NoSuchPaddingException, InvalidKeyException,
InvalidAlgorithmParameterException, IllegalBlockSizeException,
BadPaddingException, UnsupportedEncodingException,
NoSuchProviderException {
// initialize the secret key with the appropriate algorithm
SecretKeySpec skeySpec = new SecretKeySpec(aesKey, ALGORITHM);
// get an instance of the symmetric cipher
Cipher aesCipher = Cipher.getInstance(ALGORITHM + PADDING_MODE,
CRYPTO_PROVIDER);
// set it to decrypt mode with the AES key, and IV
aesCipher.init(Cipher.DECRYPT_MODE, skeySpec,
new IvParameterSpec(aesIV));
// decrypt and return the data
byte[] decryptedData = aesCipher.doFinal(encryptedData);
return decryptedData;
}
private byte[] decryptWithRSA(byte[] encryptedAesKey, PrivateKey privKey)
throws IllegalBlockSizeException, BadPaddingException,
InvalidKeyException, NoSuchAlgorithmException,
NoSuchPaddingException, NoSuchProviderException {
// get an instance of the RSA Cipher
Cipher rsaCipher = Cipher.getInstance(RSA_ALGORITHM, CRYPTO_PROVIDER);
// set the cipher to use the public key
rsaCipher.init(Cipher.DECRYPT_MODE, privKey);
// encrypt the aesKey
return rsaCipher.doFinal(encryptedAesKey);
}
C# .Net:
public byte[] encryptData(byte[] data, out byte[] encryptedAesKey, out byte[] aesIV) {
if (data == null)
throw new ArgumentNullException("data");
byte[] encryptedData; // data to return
// begin AES key generation
RijndaelManaged aesAlg = new RijndaelManaged();
aesAlg.KeySize = AES_KEY_SIZE;
aesAlg.GenerateKey();
aesAlg.GenerateIV();
aesAlg.Mode = CipherMode.CBC;
aesAlg.Padding = PaddingMode.PKCS7;
// aes Key to be encrypted
byte[] aesKey = aesAlg.Key;
// aes IV that is passed back by reference
aesIV = aesAlg.IV;
//get a new RSA crypto service provider to encrypt the AES key with the certificates public key
using (RSACryptoServiceProvider rsaCSP = new RSACryptoServiceProvider())
{
//add the certificates public key to the RSA crypto provider
rsaCSP.FromXmlString(encryptionCertificate.PublicKey.Key.ToXmlString(false));
//encrypt AES key with RSA Public key
//passed back by reference
encryptedAesKey = rsaCSP.Encrypt(aesKey, false);
//get an aes encryptor instance
ICryptoTransform aesEncryptor = aesAlg.CreateEncryptor();
encryptedData = encryptWithAes(aesEncryptor, data);
}
if (encryptedData == null)
throw new CryptographicException(
"Fatal error while encrypting with AES");
return encryptedData;
}
private byte[] encryptWithAes(ICryptoTransform aesEncryptor, byte[] data) {
MemoryStream memStream = null; // stream to write encrypted data to
CryptoStream cryptoStream = null; // crypto stream to encrypted data
try {
memStream = new MemoryStream();
// initiate crypto stream telling it to write the encrypted data to
// the memory stream
cryptoStream = new CryptoStream(memStream, aesEncryptor,
CryptoStreamMode.Write);
// write the data to the memory stream
cryptoStream.Write(data, 0, data.Length);
} catch (Exception ee) {
// rethrow
throw new Exception("Error while encrypting with AES: ", ee);
} finally {
// close 'em
if (cryptoStream != null)
cryptoStream.Close();
if (memStream != null)
memStream.Close();
}
// return the encrypted data
return memStream.ToArray();
}