text: /*******************************************************************************
  * Copyright 2016-2020 Intel Corporation
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *******************************************************************************/
  
  /*
  //  Purpose:
  //     Cryptography Primitive.
  //     RSAES-OAEP Encryption/Decription Functions
  //
  //  Contents:
  //        ippsRSAEncrypt_OAEP_rmf()
  //
  */
  
  #include "owndefs.h"
  #include "owncp.h"
  #include "pcptool.h"
  #include "pcpngrsa.h"
  #include "pcphash_rmf.h"
  
  /*F*
  // Name: ippsRSAEncrypt_OAEP_rmf
  //
  // Purpose: Performs RSAES-OAEP encryprion scheme
  //
  // Returns:                   Reason:
  //    ippStsNullPtrErr           NULL == pKey
  //                               NULL == pSrc
  //                               NULL == pDst
  //                               NULL == pLabel
  //                               NULL == pSeed
  //                               NULL == pMethod
  //                               NULL == pBuffer
  //
  //    ippStsLengthErr            srcLen <0
  //                               labLen <0
  //                               srcLen > RSAsize -2*hashLen -2
  //                               RSAsize < 2*hashLen +2
  //
  //    ippStsContextMatchErr      !RSA_PUB_KEY_VALID_ID()
  //
  //    ippStsIncompleteContextErr public key is not set up
  //
  //    ippStsNoErr                no error
  //
  // Parameters:
  //    pSrc        pointer to the plaintext
  //    srcLen      plaintext length (bytes)
  //    pLabel      (optional) pointer to the label associated with plaintext
  //    labLen      label length (bytes)
  //    pSeed       seed string of hashLen size
  //    pDst        pointer to the ciphertext (length of pdst is not less then size of RSA modulus)
  //    pKey        pointer to the RSA public key context
  //    pMethod     hash methods
  //    pBuffer     pointer to scratch buffer
  *F*/
  IPPFUN(IppStatus, ippsRSAEncrypt_OAEP_rmf,(const Ipp8u* pSrc, int srcLen,
                                             const Ipp8u* pLabel, int labLen, 
                                             const Ipp8u* pSeed,
                                                   Ipp8u* pDst,
                                             const IppsRSAPublicKeyState* pKey,
                                             const IppsHashMethod* pMethod,
                                                   Ipp8u* pScratchBuffer))
  {
     int hashLen;
  
     /* test data pointer */
     IPP_BAD_PTR4_RET(pSrc, pDst, pSeed, pMethod);
  
     IPP_BADARG_RET(!pLabel && labLen, ippStsNullPtrErr);
  
     /* test public key context */
     IPP_BAD_PTR2_RET(pKey, pScratchBuffer);
     IPP_BADARG_RET(!RSA_PUB_KEY_VALID_ID(pKey), ippStsContextMatchErr);
     IPP_BADARG_RET(!RSA_PUB_KEY_IS_SET(pKey), ippStsIncompleteContextErr);
  
     /* test length */
     IPP_BADARG_RET(srcLen<0||labLen<0, ippStsLengthErr);
  
      hashLen = pMethod->hashLen;
     /* test compatibility of RSA and hash length */
     IPP_BADARG_RET(BITS2WORD8_SIZE(RSA_PRV_KEY_BITSIZE_N(pKey)) < (2*hashLen +2), ippStsLengthErr);
     /* test compatibility of msg length and other (RSA and hash) lengths */
     IPP_BADARG_RET(BITS2WORD8_SIZE(RSA_PRV_KEY_BITSIZE_N(pKey))-(2*hashLen +2) < srcLen, ippStsLengthErr);
  
     {
        /* size of RSA modulus in bytes and chunks */
        int k = BITS2WORD8_SIZE(RSA_PUB_KEY_BITSIZE_N(pKey));
        cpSize nsN = BITS_BNU_CHUNK(RSA_PUB_KEY_BITSIZE_N(pKey));
  
        /*
        // EME-OAEP encoding
        */
        {
           Ipp8u  seedMask[BITS2WORD8_SIZE(IPP_SHA512_DIGEST_BITSIZE)];
  
           Ipp8u* pMaskedSeed = pDst+1;
           Ipp8u* pMaskedDB = pDst +hashLen +1;
  
           pDst[0] = 0;
  
           /* maskedDB = MGF(seed, k-1-hashLen)*/
           ippsMGF1_rmf(pSeed, hashLen, pMaskedDB, k-1-hashLen, pMethod);
  
           /* seedMask = HASH(pLab) */
           ippsHashMessage_rmf(pLabel, labLen, seedMask, pMethod);
  
           /* maskedDB ^= concat(HASH(pLab),PS,0x01,pSc) */
           XorBlock(pMaskedDB, seedMask, pMaskedDB, hashLen);
           pMaskedDB[k-srcLen-hashLen-2] ^= 0x01;
           XorBlock(pMaskedDB+k-srcLen-hashLen-2+1, pSrc, pMaskedDB+k-srcLen-hashLen-2+1, srcLen);
  
           /* seedMask = MGF(maskedDB, hashLen) */
           ippsMGF1_rmf(pMaskedDB, k-1-hashLen, seedMask, hashLen, pMethod);
           /* maskedSeed = seed ^ seedMask */
           XorBlock(pSeed, seedMask, pMaskedSeed, hashLen);
        }
  
        /* RSA encryption */
        {
           /* align buffer */
           BNU_CHUNK_T* pBuffer = (BNU_CHUNK_T*)(IPP_ALIGNED_PTR(pScratchBuffer, (int)sizeof(BNU_CHUNK_T)) );
  
           /* temporary BN */
           __ALIGN8 IppsBigNumState tmpBN;
           BN_Make(pBuffer, pBuffer+nsN+1, nsN, &tmpBN);
  
           /* updtae buffer pointer */
           pBuffer += (nsN+1)*2;
  
           ippsSetOctString_BN(pDst, k, &tmpBN);
  
           gsRSApub_cipher(&tmpBN, &tmpBN, pKey, pBuffer);
  
           ippsGetOctString_BN(pDst, k, &tmpBN);
        }
  
        return ippStsNoErr;
     }
  }
  