CODEWITHSUNDEEP
iphoneobjective-ciosaes
khurram shahzad
khurram shahzad

Reputation: 23

AES algorithm implementation in iOS

Hi all I am struggling in converting AES algorithm .net code to objective c. I go through different API's but results are always different .net code provided by client I am not a .net developer so i am struggling. Any suggestions or code snippet is appreciated .net code is as under.

 Public Function AES_Encrypt(ByVal input As String, ByVal pass As String) As String
            Dim AES As New System.Security.Cryptography.RijndaelManaged
            Dim Hash_AES As New System.Security.Cryptography.MD5CryptoServiceProvider
            Dim encrypted As String = ""
            Try
                Dim hash(31) As Byte
                Dim temp As Byte() =     Hash_AES.ComputeHash(System.Text.ASCIIEncoding.ASCII.GetBytes(pass))
                Array.Copy(temp, 0, hash, 0, 16)
                Array.Copy(temp, 0, hash, 15, 16)
                AES.Key = hash
                AES.Mode = Security.Cryptography.CipherMode.ECB
              Dim DESEncrypter As System.Security.Cryptography.ICryptoTransform = AES.CreateEncryptor
            Dim Buffer As Byte() = System.Text.ASCIIEncoding.ASCII.GetBytes(input)
            encrypted = Convert.ToBase64String(DESEncrypter.TransformFinalBlock(Buffer, 0, Buffer.Length))
        Catch ex As Exception
        End Try
        Return encrypted
    End Function
 
 
 
    Public Function AES_Decrypt(ByVal input As String, ByVal pass As String) As String
        Dim AES As New System.Security.Cryptography.RijndaelManaged
        Dim Hash_AES As New System.Security.Cryptography.MD5CryptoServiceProvider
        Dim decrypted As String = ""
        Try
            Dim hash(31) As Byte
            Dim temp As Byte() = Hash_AES.ComputeHash(System.Text.ASCIIEncoding.ASCII.GetBytes(pass))
            Array.Copy(temp, 0, hash, 0, 16)
            Array.Copy(temp, 0, hash, 15, 16)
            AES.Key = hash
            AES.Mode = Security.Cryptography.CipherMode.ECB
            Dim DESDecrypter As System.Security.Cryptography.ICryptoTransform = AES.CreateDecryptor
            Dim Buffer As Byte() = Convert.FromBase64String(input)
            decrypted = System.Text.ASCIIEncoding.ASCII.GetString(DESDecrypter.TransformFinalBlock(Buffer, 0, Buffer.Length))
 
        Catch ex As Exception
        End Try
        Return decrypted
    End Function*

Upvotes: 0

Views: 1196

Answers (1)

ıɾuǝʞ
ıɾuǝʞ

Reputation: 2849

In iOS, you can the CommonCrypto API :

size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,
                                      keyPtr, keySize,
                                      NULL /* initialization vector (optional) */,
                                      [someData bytes], dataLength, /* input */
                                      buffer, bufferSize, /* output */
                                      &numBytesEncrypted);
if (cryptStatus == kCCSuccess) {
    //the returned NSData takes ownership of the buffer and will free it on deallocation
    return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
}

And to decrypt :

size_t numBytesDecrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,
                                      keyPtr, keySize,
                                      NULL /* initialization vector (optional) */,
                                      [self bytes], dataLength, /* input */
                                      buffer, bufferSize, /* output */
                                      &numBytesDecrypted);

if (cryptStatus == kCCSuccess) {
    //the returned NSData takes ownership of the buffer and will free it on deallocation
    return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
}

Upvotes: 3

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