topic Re: Variable-value encryption in SAS in SAS Programming

Variable-value encryption in SAS

AlexBennasar — Wed, 06 Jul 2022 17:49:51 GMT

Hi all!

I've been programming with SAS in my job for 6 years. One thing I miss in Base SAS is the functionality of encrypting a single value or a collection of them, like a variable in a dataset. I'm not talking about hashing a variable, nor encrypting the entire dataset...I want to genuinely encrypt and decrypt values, with AES, PKCS, etc.

I have initiated a project to develop code (100% SAS code) to implement this functionality. For now, the basic AES algorithm for encrypting and decrypting basic 128 bits-lengh blocks is done. You can encrypt them with a single macro call:

/* Message to be encrypted */
%let message=00112233445566778899aabbccddeeff;
%put NOTE: Original message: &message;

/* Encryption with a 128-bit key */
%let key128=000102030405060708090a0b0c0d0e0f;
%let cryptogram128=%cipherAES(&message, &key128);
%put NOTE: Message encrypted with 128-bit key: &cryptogram128;

and then decrypt with another call:

/* Decryption with a 128-bit key */
%let messageDecrypted128=%invCipherAES(&cryptogram128, &key128);
%put NOTE: Message decrypted with 128-bit key: &messageDecrypted128;

The encryption key can have 3 lengths: 128, 192 and 256 bit, according to the AES:

/* Encryption with a 192-bit key */
%let key192=000102030405060708090a0b0c0d0e0f1011121314151617;
%let cryptogram192=%cipherAES(&message, &key192);
%put NOTE: Message encrypted with 192-bit key: &cryptogram192;

/* Encryption with a 256-bit key */
%let key256=000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f;
%let cryptogram256=%cipherAES(&message, &key256);
%put NOTE: Message encrypted with 256-bit key: &cryptogram256;

These macros are, in fact, macrofunctions, but they can encrypt the N values of a dataset variable too:

/* Compute cryptograms and store them in macrovar */
proc sql noprint;
	select '%cipherAES('||m||','||k||')' into :cryptograms separated by ' ' from testMessages;
quit;

The project is a work in progress. To be fully functional, it will be needed at least:

a key derivation function
a block cypher mode of operation
a padding scheme

For now, the AES protocol implementation is all I have done. The project can be found here:

https://github.com/AlexBennasar/Crypto-SAS

Maybe this project will be interesting/useful for somebody!

Re: Variable-value encryption in SAS

SASKiwi — Wed, 06 Jul 2022 19:55:01 GMT

@AlexBennasar - This is great, but I think you should post this in the Community Library as an article to get better visibility. You can do that here: SAS Support Communities

Re: Variable-value encryption in SAS

AlexBennasar — Wed, 06 Jul 2022 20:01:48 GMT

Sure, unfortunately I still can't create an article there 😞 but thanks for that feedback! I'll do it in near future, I hope

Re: Variable-value encryption in SAS

SASKiwi — Wed, 06 Jul 2022 20:49:50 GMT

@AlexBennasar - Maybe someone can sort that out for you. Calling @ShelleySessoms ...

Re: Variable-value encryption in SAS

AlexBennasar — Thu, 07 Jul 2022 04:54:33 GMT

Thanks for your help!

Re: Variable-value encryption in SAS

Ksharp — Thu, 07 Jul 2022 11:53:00 GMT

It is awesome. As SASKiwi said it would be better to post this in the Community Library.

Re: Variable-value encryption in SAS

AlexBennasar — Thu, 07 Jul 2022 15:34:39 GMT

Thanks for the feedback! I'll post it there whenever I can

Re: Variable-value encryption in SAS

ShelleySessoms — Mon, 11 Jul 2022 11:41:01 GMT

The article is live now: https://communities.sas.com/t5/SAS-Communities-Library/Variable-value-encryption-in-SAS/ta-p/822231