Added support for OAEP padding to RSA encryption/decryption. (#120)

Co-authored-by: Jason Law <[email protected]>
jeroen · Oct 5, 2023 · 5302c6f · 5302c6f
1 parent 634c885
commit 5302c6f
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Showing 3 changed files with 15 additions and 10 deletions.
diff --git a/R/rsa.R b/R/rsa.R
@@ -8,6 +8,7 @@
 #'
 #' @export
 #' @param data raw vector of max 245 bytes (for 2048 bit keys) with data to encrypt/decrypt
+#' @param oaep if TRUE, changes padding to EME-OAEP as defined in PKCS #1 v2.0
 #' @inheritParams signature_create
 #' @rdname rsa_encrypt
 #' @aliases rsa encrypt
@@ -28,19 +29,19 @@
 #' tempkey <- rsa_decrypt(ciphertext, key)
 #' message <- aes_cbc_decrypt(blob, tempkey, iv)
 #' out <- rawToChar(message)
-rsa_encrypt <- function(data, pubkey = my_pubkey()){
+rsa_encrypt <- function(data, pubkey = my_pubkey(), oaep = FALSE){
   pk <- read_pubkey(pubkey)
   stopifnot(inherits(pk, "rsa"))
   stopifnot(is.raw(data))
-  .Call(R_rsa_encrypt, data, pk)
+  .Call(R_rsa_encrypt, data, pk, oaep)
 }
 
 #' @useDynLib openssl R_rsa_decrypt
 #' @export
 #' @rdname rsa_encrypt
-rsa_decrypt <- function(data, key = my_key(), password = askpass){
+rsa_decrypt <- function(data, key = my_key(), password = askpass, oaep = FALSE){
   sk <- read_key(key, password)
   stopifnot(inherits(sk, "rsa"))
   stopifnot(is.raw(data))
-  .Call(R_rsa_decrypt, data, sk)
+  .Call(R_rsa_decrypt, data, sk, oaep)
 }
diff --git a/man/rsa_encrypt.Rd b/man/rsa_encrypt.Rd
diff --git a/src/rsa.c b/src/rsa.c
@@ -5,13 +5,14 @@
 #include <openssl/pem.h>
 #include "utils.h"
 
-SEXP R_rsa_encrypt(SEXP data, SEXP keydata) {
+SEXP R_rsa_encrypt(SEXP data, SEXP keydata, SEXP oaep) {
   const unsigned char *ptr = RAW(keydata);
   RSA *rsa = d2i_RSA_PUBKEY(NULL, &ptr, LENGTH(keydata));
+  int pad = asLogical(oaep) ? RSA_PKCS1_OAEP_PADDING : RSA_PKCS1_PADDING;
   bail(!!rsa);
   int keysize = RSA_size(rsa);
   unsigned char* buf = OPENSSL_malloc(keysize);
-  int len = RSA_public_encrypt(LENGTH(data), RAW(data), buf, rsa, RSA_PKCS1_PADDING);
+  int len = RSA_public_encrypt(LENGTH(data), RAW(data), buf, rsa, pad);
   bail(len > 0);
   RSA_free(rsa);
   SEXP res = allocVector(RAWSXP, len);
@@ -20,13 +21,14 @@ SEXP R_rsa_encrypt(SEXP data, SEXP keydata) {
   return res;
 }
 
-SEXP R_rsa_decrypt(SEXP data, SEXP keydata){
+SEXP R_rsa_decrypt(SEXP data, SEXP keydata, SEXP oaep){
   const unsigned char *ptr = RAW(keydata);
   RSA *rsa = d2i_RSAPrivateKey(NULL, &ptr, LENGTH(keydata));
+  int pad = asLogical(oaep) ? RSA_PKCS1_OAEP_PADDING : RSA_PKCS1_PADDING;
   bail(!!rsa);
   int keysize = RSA_size(rsa);
   unsigned char* buf = OPENSSL_malloc(keysize);
-  int len = RSA_private_decrypt(LENGTH(data), RAW(data), buf, rsa, RSA_PKCS1_PADDING);
+  int len = RSA_private_decrypt(LENGTH(data), RAW(data), buf, rsa, pad);
   bail(len > 0);
   RSA_free(rsa);
   SEXP res = allocVector(RAWSXP, len);