对称加密示例
示例 9–2 在 CBC（密码块链接）模式下使用 DES 算法为加密创建了密钥对象。此源代码执行以下步骤：
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声明密钥材料。
定义 DES 和初始化向量。以静态方式声明的初始化向量仅用于说明，初始化向量应始终以动态方式定义并且永远不会重用。
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定义密钥对象。
对于此任务，必须为密钥设置模板。
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查找适用于指定加密机制的插槽。
此示例使用 Sun 的便利函数 SUNW_C_GetMechSession()。SUNW_C_GetMechSession() 用于打开 cryptoki 库，该库用于存放 Solaris 加密框架中所使用的全部 PKCS #11 函数。SUNW_C_GetMechSession() 随后使用所需的机制来查找插槽。然后，将会启动会话。这个便利函数可有效地替换 C_Initialize() 调用、C_OpenSession() 调用以及查找支持指定机制的插槽所需的任何代码。
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在插槽中执行加密操作。
此任务中的加密可通过以下几个步骤执行：
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在插槽中执行解密操作。
此任务中的解密可通过以下两个步骤执行。提供解密的目的仅是为了进行测试。
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结束会话。
程序使用 C_CloseSession() 关闭会话，使用 C_Finalize() 关闭库。
以下示例中显示了对称加密示例的源代码。
注 –
此示例的源代码也可以通过 Sun 下载中心获取。请访问 http://www.sun.com/download/products.xml?id=41912db5
示例 9–2 使用 PKCS #11 函数创建加密密钥对象
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/types.h>
#include <security/cryptoki.h>
#include <security/pkcs11.h>
#define BUFFERSIZ 8192
/* Declare values for the key materials. DO NOT declare initialization
* vectors statically like this in real life!! */
uchar_t des_key[] = { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef};
uchar_t des_cbc_iv[] = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xab, 0xcd, 0xef};
/* Key template related definitions. */
static CK_BBOOL truevalue = TRUE;
static CK_BBOOL falsevalue = FALSE;
static CK_OBJECT_CLASS class = CKO_SECRET_KEY;
static CK_KEY_TYPE keyType = CKK_DES;
/* Example encrypts and decrypts a file provided by the user. */
void
main(int argc, char **argv)
{
CK_RV rv;
CK_MECHANISM mechanism;
CK_OBJECT_HANDLE hKey;
CK_SESSION_HANDLE hSession;
CK_ULONG ciphertext_len = 64, lastpart_len = 64,
ciphertext_space = BUFFERSIZ;
CK_ULONG decrypttext_len;
CK_ULONG total_encrypted = 0;
CK_ULONG ulDatalen = BUFFERSIZ;
CK_SLOT_ID SlotID;
int *pi, i, bytes_read = 0;
int error = 0;
char inbuf[BUFFERSIZ];
FILE *fs;
uchar_t *ciphertext, *pciphertext, *decrypttext;
/* Set the key object */
CK_ATTRIBUTE template[] = {
{CKA_CLASS, &class, sizeof (class) },
{CKA_KEY_TYPE, &keyType, sizeof (keyType) },
{CKA_TOKEN, &falsevalue, sizeof (falsevalue) },
{CKA_ENCRYPT, &truevalue, sizeof (truevalue) },
{CKA_VALUE, &des_key, sizeof (des_key) }
};
/* Set the encryption mechanism to CKM_DES_CBC_PAD */
mechanism.mechanism = CKM_DES_CBC_PAD;
mechanism.pParameter = des_cbc_iv;
mechanism.ulParameterLen = 8;
/* Use SUNW convenience function to initialize the cryptoki
* library, and open a session with a slot that supports
* the mechanism we plan on using. */
rv = SUNW_C_GetMechSession(mechanism.mechanism, &hSession);
if (rv != CKR_OK) {
fprintf(stderr, "SUNW_C_GetMechSession: rv = 0x%.8X\n", rv);
exit(1);
}
/* Open the input file */
if ((fs = fopen(argv[1], "r")) == NULL) {
perror("fopen");
fprintf(stderr, "\n\tusage: %s filename>\n", argv[0]);
error = 1;
goto exit_session;
}
/* Create an object handle for the key */
rv = C_CreateObject(hSession, template,
sizeof (template) / sizeof (CK_ATTRIBUTE),
&hKey);
if (rv != CKR_OK) {
fprintf(stderr, "C_CreateObject: rv = 0x%.8X\n", rv);
error = 1;
goto exit_session;
}
/* Initialize the encryption operation in the session */
rv = C_EncryptInit(hSession, &mechanism, hKey);
if (rv != CKR_OK) {
fprintf(stderr, "C_EncryptInit: rv = 0x%.8X\n", rv);
error = 1;
goto exit_session;
}
/* Read in the data and encrypt this portion */
pciphertext = &ciphertext[0];
while (!feof(fs) && (ciphertext_space > 0) &&
(ulDatalen = fread(inbuf, 1, ciphertext_space, fs)) > 0) {
ciphertext_len = ciphertext_space;
/* C_EncryptUpdate is only being sent one byte at a
* time, so we are not checking for CKR_BUFFER_TOO_SMALL.
* Also, we are checking to make sure we do not go
* over the alloted buffer size. A more robust program
* could incorporate realloc to enlarge the buffer
* dynamically. */
rv = C_EncryptUpdate(hSession, (CK_BYTE_PTR)inbuf, ulDatalen,
pciphertext, &ciphertext_len);
if (rv != CKR_OK) {
fprintf(stderr, "C_EncryptUpdate: rv = 0x%.8X\n", rv);
error = 1;
goto exit_encrypt;
}
pciphertext += ciphertext_len;
total_encrypted += ciphertext_len;
ciphertext_space -= ciphertext_len;
bytes_read += ulDatalen;
}
if (!feof(fs) || (ciphertext_space < 0)) {
fprintf(stderr, "Insufficient space for encrypting the file\n");
error = 1;
goto exit_encrypt;
}
/* Get the last portion of the encrypted data */
lastpart_len = ciphertext_space;
rv = C_EncryptFinal(hSession, pciphertext, &lastpart_len);
if (rv != CKR_OK) {
fprintf(stderr, "C_EncryptFinal: rv = 0x%.8X\n", rv);
error = 1;
goto exit_encrypt;
}
total_encrypted += lastpart_len;
fprintf(stdout, "%d bytes read and encrypted. Size of the "
"ciphertext: %d!\n\n", bytes_read, total_encrypted);
/* Print the encryption results */
fprintf(stdout, "The value of the encryption is:\n");
for (i = 0; i < ciphertext_len; i++) {
if (ciphertext[i] < 16)
fprintf(stdout, "0%x", ciphertext[i]);
else
fprintf(stdout, "%2x", ciphertext[i]);
}
/* Initialize the decryption operation in the session */
rv = C_DecryptInit(hSession, &mechanism, hKey);
/* Decrypt the entire ciphertext string */
decrypttext_len = sizeof (decrypttext);
rv = C_Decrypt(hSession, (CK_BYTE_PTR)ciphertext, total_encrypted,
decrypttext, &decrypttext_len);
if (rv != CKR_OK) {
fprintf(stderr, "C_Decrypt: rv = 0x%.8X\n", rv);
error = 1;
goto exit_encrypt;
}
fprintf(stdout, "\n\n%d bytes decrypted!!!\n\n", decrypttext_len);
/* Print the decryption results */
fprintf(stdout, "The value of the decryption is:\n%s", decrypttext);
fprintf(stdout, "\nDone!!!\n");
exit_encrypt:
fclose(fs);
exit_session:
(void) C_CloseSession(hSession);
exit_program:
(void) C_Finalize(NULL_PTR);
exit(error);
}
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