/*
* Decrypt a feeCipherFile obtained via feeCFileNewFromDataRep().
* recvPrivKey is required in all cases. If sendPubKey is present,
* sendPubKey - rather than the embedded sender's public key - will be
* used for signature validation.
*/
feeReturn decryptCipherFile(feeCipherFile cipherFile,
feePubKey recvPrivKey, // required
feePubKey sendPubKey, // optional, for signature
unsigned char **plainText, // malloc'd & RETURNED
unsigned *plainTextLen, // RETURNED
feeSigStatus *sigStatus) // RETURNED
{
cipherFileEncrType encrType = feeCFileEncrType(cipherFile);
feeReturn frtn;
*plainText = NULL;
*plainTextLen = 0;
/*
* Dispatch to encrType-specific code.
*/
switch(encrType) {
case CFE_RandDES:
frtn = decryptRandDES(cipherFile,
recvPrivKey,
sendPubKey,
plainText,
plainTextLen,
sigStatus);
break;
case CFE_PublicDES:
frtn = decryptPubDES(cipherFile,
recvPrivKey,
sendPubKey,
plainText,
plainTextLen,
sigStatus);
break;
case CFE_FEED:
frtn = decryptFEED(cipherFile,
recvPrivKey,
sendPubKey,
plainText,
plainTextLen,
sigStatus);
break;
case CFE_FEEDExp:
frtn = decryptFEEDExp(cipherFile,
recvPrivKey,
sendPubKey,
plainText,
plainTextLen,
sigStatus);
break;
default:
frtn = FR_Unimplemented;
break;
}
return frtn;
}
/*
* Parse a cipherfile.
*
* sendPubKey only needed for cipherFileEncrType CFE_RandDES if signature
* is present. If sendPubKey is present, it will be used for signature
* validation rather than the embedded sender's public key.
*/
feeReturn parseCipherFile(feePubKey recvPrivKey,
feePubKey sendPubKey,
const unsigned char *cipherFileData,
unsigned cipherFileDataLen,
int doDec64, // 1 ==> perform dec64
cipherFileEncrType *encrType, // RETURNED
unsigned char **plainText, // RETURNED
unsigned *plainTextLen, // RETURNED
feeSigStatus *sigStatus, // RETURNED
unsigned *userData) // RETURNED
{
feeReturn frtn;
unsigned char *cipherData = NULL;
unsigned cipherDataLen;
int freeCipherData = 0;
feeCipherFile cipherFile = NULL;
*plainText = NULL;
*plainTextLen = 0;
if(recvPrivKey == NULL) { // always required
frtn = FR_BadPubKey;
goto out;
}
/*
* First, optional dec64()
*/
if(doDec64) {
cipherData = dec64(cipherFileData,
cipherFileDataLen,
&cipherDataLen);
if(cipherData == NULL) {
frtn = FR_BadEnc64;
goto out;
}
else {
freeCipherData = 1;
}
}
else {
cipherData = (unsigned char *)cipherFileData;
cipherDataLen = cipherFileDataLen;
}
/*
* Cons up a feeCipherFile object.
*/
frtn = feeCFileNewFromDataRep(cipherData,
cipherDataLen,
&cipherFile);
if(frtn) {
goto out;
}
*encrType = feeCFileEncrType(cipherFile);
*userData = feeCFileUserData(cipherFile);
frtn = decryptCipherFile(cipherFile,
recvPrivKey,
sendPubKey,
plainText,
plainTextLen,
sigStatus);
out:
/* free stuff */
if(cipherData && freeCipherData) {
ffree(cipherData);
}
if(cipherFile) {
feeCFileFree(cipherFile);
}
return frtn;
}
feeReturn decryptFEEDExp(feeCipherFile cipherFile,
feePubKey recvPrivKey,
feePubKey sendPubKey, // optional
unsigned char **plainText, // RETURNED
unsigned *plainTextLen, // RETURNED
feeSigStatus *sigStatus) // RETURNED
{
feeReturn frtn = FR_Success;
unsigned char *cipherText = NULL;
unsigned cipherTextLen;
feeFEEDExp feed = NULL;
unsigned char *sigData = NULL;
unsigned sigDataLen;
unsigned char *sendPubKeyStr = NULL;
unsigned sendPubKeyStrLen = 0;
feePubKey parsedSendPubKey = NULL;
if(feeCFileEncrType(cipherFile) != CFE_FEEDExp) {
frtn = FR_Internal;
goto out;
}
/*
* Get ciphertext from cipherFile
*/
cipherText = feeCFileCipherText(cipherFile, &cipherTextLen);
if(cipherText == NULL) {
frtn = FR_BadCipherFile;
goto out;
}
/*
* FEEDExp decrypt
*/
feed = feeFEEDExpNewWithPubKey(recvPrivKey, NULL, NULL);
if(feed == NULL) {
frtn = FR_BadPubKey;
goto out;
}
frtn = feeFEEDExpDecrypt(feed,
cipherText,
cipherTextLen,
plainText,
plainTextLen);
if(frtn) {
goto out;
}
sigData = feeCFileSigData(cipherFile, &sigDataLen);
if(sigData) {
feeReturn sigFrtn;
if(sendPubKey == NULL) {
/*
* use embedded sender's public key
*/
sendPubKeyStr = feeCFileSendPubKeyData(cipherFile,
&sendPubKeyStrLen);
if(sendPubKeyStr == NULL) {
frtn = FR_BadCipherFile;
goto out;
}
parsedSendPubKey = feePubKeyAlloc();
frtn = feePubKeyInitFromKeyString(parsedSendPubKey,
(char *)sendPubKeyStr, sendPubKeyStrLen);
if(frtn) {
frtn = FR_BadCipherFile;
goto out;
}
sendPubKey = parsedSendPubKey;
}
sigFrtn = feePubKeyVerifySignature(sendPubKey,
cipherText,
cipherTextLen,
sigData,
sigDataLen);
switch(sigFrtn) {
case FR_Success:
*sigStatus = SS_PresentValid;
break;
default:
*sigStatus = SS_PresentInvalid;
break;
}
}
else {
*sigStatus = SS_NotPresent;
}
out:
if(cipherText) {
ffree(cipherText);
}
if(feed) {
feeFEEDExpFree(feed);
}
if(sigData) {
ffree(sigData);
}
if(parsedSendPubKey) {
feePubKeyFree(parsedSendPubKey);
}
if(sendPubKeyStr) {
ffree(sendPubKeyStr);
}
return frtn;
}
