私钥解密代码使用公共接口说明符到 BSAFE 库 v6.0?

Question

我最近被赋予了升级一段非常旧的加密代码的责任，该代码将不再在Windows 10下运行。 我升级到Visual Studio 2013，并稍微修改了代码以使用更好的错误报告。 并且代码工作正常。 它使用私钥来解密加密数据。 一切都很好。

除了当我注意到代码中的注释指示某些 PUBLIC 说明符必须用作 BSAFE v6.0 库例程的输入，而不是它们的 PRIVATE 对应项时。 实际上，当使用私有说明符时，我收到以下错误消息：

RSA 错误：密钥信息格式无效

注意：我的私钥未加密。

我很困惑为什么私有说明符不起作用，因为我正在做私钥解密。

在下面的代码中，BSAFE v6.0 库函数B_SetKeyInfo、B_GetKeyInfo和B_SetAlgorithmInfo使用公钥说明符。

int Decrypt(unsigned char* cypherData, const string privKeyFilePathAndName, unsigned char*& plainData) {
enum { 
IN_BUF_LEN                  = 1000, // input buffer length
NUM_DIGITAL_SIGNATURE_BYTES = 128   // number of digital signature bytes
}; 
static unsigned char decryptedDigest[NUM_DIGITAL_SIGNATURE_BYTES]; // decrypted digest (returned)
const string delimiters = " n"; // strtok delimeters
A_RSA_KEY       privKey;                             // private key
B_ALGORITHM_OBJ rsaAlgorithmObj;                     // rsa algorithm object
B_KEY_OBJ       privKeyObject;                       // private key object
char            inBuf[IN_BUF_LEN];                   // input buffer
char*           token;                               // strtok token
FILE*           ifp;                                 // input (private key) file pointer
int             i;                                   // index
int             stat;                                // status
unsigned char   privModulusData[NUM_MODULUS_BYTES];  // modulus data
unsigned char   privExponentData[NUM_MODULUS_BYTES]; // exponent data
unsigned int    digestLen;                           // digest length
unsigned int    partOutLen;                          // part out length
// open private key file
if ((ifp = fopen(privKeyFilePathAndName.c_str(), "r")) == NULL) {
DisplayErrorMsg("Can't open private key file");
return FAIL;
}
// get modulus length and exponent length
if ((fgets(inBuf, IN_BUF_LEN, ifp)) == NULL) {
DisplayErrorMsg("Private key file error - can't read number of modulus bytes (modulus length)");
return FAIL;
}
privKey.modulus.len = privKey.exponent.len = stoi(inBuf);
// get modulus data
if ((fgets(inBuf, IN_BUF_LEN, ifp)) == NULL) {
DisplayErrorMsg("Private key file error - can't read modulus data");
return FAIL;
}
token = strtok(inBuf, delimiters.c_str());
for (i = 0; token; i++) {
privModulusData[i] = (unsigned char) stoi(token);
token = strtok(NULL, delimiters.c_str());
}
if (i != sizeof(privModulusData)) {
DisplayErrorMsg("Private key file error - wrong amount of modulus data");
return FAIL;
}
// get exponent data
if ((fgets(inBuf, IN_BUF_LEN, ifp)) == NULL) {
DisplayErrorMsg("Private key file error - can't read exponent data");
return FAIL;
}
token = strtok(inBuf, delimiters.c_str());
for (i = 0; token; i++) {
privExponentData[i] = (unsigned char) stoi(token);
token = strtok(NULL, delimiters.c_str());
}
if (i != sizeof(privExponentData)) {
DisplayErrorMsg("Private key file error - wrong amount of exponent data");
return FAIL;
}
// close private key file and finish creating private key variable
fclose(ifp);
privKey.modulus.data = privModulusData;
privKey.exponent.data = privExponentData;
// create private key object and set to key read in from file
if ((stat = B_CreateKeyObject(&privKeyObject)) != 0) {
DisplayRsaErrorMsg(stat);
return FAIL;
}
// the private key is set to an Infotype of KI_RSAPublic because an error is 
// generated during decryption if we use the Infotype KI_RSAPrivate; not sure 
// why it works this way
if ((stat = B_SetKeyInfo(privKeyObject, KI_RSAPublic, (POINTER)&privKey)) != 0) {
DisplayRsaErrorMsg(stat);
return FAIL;
}
if ((stat = B_GetKeyInfo((POINTER *)&privKey, privKeyObject, KI_RSAPublic)) != 0) {
DisplayRsaErrorMsg(stat);
return FAIL;
}
// create an rsa algorithm object and set algorithm infoType to RSAPublic
if ((stat = B_CreateAlgorithmObject(&rsaAlgorithmObj)) != 0) {
DisplayRsaErrorMsg(stat);
return FAIL;
}
if ((stat = B_SetAlgorithmInfo(rsaAlgorithmObj, AI_RSAPublic, NULL_PTR)) != 0) {
DisplayRsaErrorMsg(stat);
return FAIL;
}
// perform the decryption, in stages (initial, update, and final)
if ((stat = B_DecryptInit(rsaAlgorithmObj, privKeyObject, DEMO_ALGORITHM_CHOOSER, ((A_SURRENDER_CTX*)NULL_PTR))) != 0) {
DisplayRsaErrorMsg(stat);
return FAIL;
}
if ((stat = B_DecryptUpdate(rsaAlgorithmObj, decryptedDigest, &digestLen, sizeof(decryptedDigest), cypherData, NUM_DIGITAL_SIGNATURE_BYTES, (B_ALGORITHM_OBJ)NULL_PTR, ((A_SURRENDER_CTX*)NULL_PTR))) != 0) {
DisplayRsaErrorMsg(stat);
return FAIL;
}
if ((stat = B_DecryptFinal(rsaAlgorithmObj, decryptedDigest, &partOutLen, sizeof(decryptedDigest), (B_ALGORITHM_OBJ)NULL_PTR, ((A_SURRENDER_CTX*)NULL_PTR))) != 0) {
DisplayRsaErrorMsg(stat);
return FAIL;
}
// set returned pointer and return pass code
plainData = decryptedDigest;
return PASS;

}

Answer 1

RSA BSAFE Crypto-C 5.2 库参考手册指出不建议使用 KI_RSAPrivate。与 RSA 私钥一起使用的正确 KI 是KI_PKCS_RSAPrivate和KI_PKCS_RSAPrivateBER。看这里。