Use Integer List Key with Apex Crypto

Question

SO if i am given a private key as follow:

[242, 2, 56, 23, 15, 5, 12, 105, 19, 47, 116, 89, 25, 152, 200, 215]

and an initialization vector:

[194, 125, 123, 26, 93, 136, 191, 35, 20, 86, 167, 197, 12, 138, 135, 92, 233, 39, 121, 166, 8, 2, 103, 44, 239, 115, 50, 155, 200, 238, 33, 99]

How would I go about using Crypto.encrypt in Apex? The example I found all use Strings for the iV and use an auto generatedKey as shown below:

Blob exampleIv = Blob.valueOf('Example of IV123');
Blob key = Crypto.generateAesKey(128);
Blob data = Blob.valueOf('Data to be encrypted');
Blob encrypted = Crypto.encrypt('AES128', key, exampleIv, data);

Do I just do this?

String encodedString = String.fromCharArray(ivKey);

Somehow something does not feel right here, my private key as 16 numbers and my iv has 32, these are provided from a third party so I HAVE to use keys like the one I posted (the two keys I posted I generated at random for obvious security purpose). I am just trying to understand how to make this work in Apex if at all possible

Any help would be appreciated!

UPDATE:

Using the code below:

List<Integer> key = new List<Integer>{242, 2, 56, 23, 15, 5, 12, 105, 19, 47, 116, 89, 25, 152, 200, 215};
List<Integer> iv = new List<Integer>{194, 125, 123, 26, 93, 136, 191, 35, 20, 86, 167, 197, 12, 138, 135, 92, 233, 39, 121, 166, 8, 2, 103, 44, 239, 115, 50, 155, 200, 238, 33, 99};

String charkey = Base64.encode(key);
String chariV = Base64.encode(iv);
String password ='passwd9999';

Blob Blobkey =  EncodingUtil.base64Decode(charkey);
Blob BlobiV =  EncodingUtil.base64Decode(chariV);
Blob BlobPassword = Blob.valueOf(password);

Blob encrypted = Crypto.encrypt('AES128', Blobkey, BlobiV, BlobPassword);
String encryptedDataStr = EncodingUtil.base64Encode(encrypted);
System.Debug(encryptedDataStr);

with this class:

public class Base64 {
    static String[] codes = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='.split('');

    // Encodes integers 0-255 into base 64 string
    public static String encode(Integer[] source) {
        // Preallocate memory for speed
        String[] result = new String[(source.size()+2)/3];
        // Every three bytes input becomes four bytes output
        for(Integer index = 0, size = source.size()/3; index < size; index++) {
            // Combine three bytes in to one single integer
            Integer temp = (source[index]<<16|source[index+1]<<8)|source[index+2];
            // Extract four values from 0-63, and use the code from the base 64 index
            result[index]=codes[temp>>18]+(codes[(temp>>12)&63])+(codes[(temp>>6)&63])+codes[temp&63];
        }
        if(Math.mod(source.size(),3)==1) {
            // One byte left over, need two bytes padding
            Integer temp = (source[source.size()-1]<<16);
            result[result.size()-1] = codes[temp>>18]+(codes[(temp>>12)&63])+codes[64]+codes[64];
        } else if(Math.mod(source.size(),3)==2) {
            // Two bytes left over, need one byte padding
            Integer temp = (source[source.size()-2]<<16)|(source[source.size()-1]<<8);
            result[result.size()-1] = codes[temp>>18]+(codes[(temp>>12)&63])+(codes[(temp>>6)&63])+codes[64];
        }
        // Join into a single string
        return String.join(result, '');
    }
}

I get the following error:

System.InvalidParameterValueException: Invalid private key. Must be 16 bytes.

I wish I did not have to use an Integer Array but I do not have much choice in the matter!

Answer 1

We do not use a String for encryption, we use a Blob. The easiest way to get where you're trying to go is to use EncodingUtil's base64Decode function to the the format you need:

Blob exampleIv = EncodingUtil.base64Decode('yourBase64EncodedIvHere');
Blob key = EncodingUtil.base64Decode('yourBase64EncodedKeyHere');

As we discussed in your previous question, if you absolutely insist on using an Integer array, you can use the code I put in my previous answer to convert it to a base64 string, but you'll still need to use this decode method to get to the correct Blob data values.