OpenSSL对称加密算法中怎么样添加新算法

int cname_ofb_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out, const unsigned char *in, unsigned int inl);

二：四种加密模式的实现

四种加密模式与基本加解密算法之间的关系！

假设加密算法和解密算法的实现函数接口如下

void encrypt(const unsigned char *in, unsigned char *out, const KEY *key, int *length)

void decrypt(const unsigned char *in, unsigned char *out, const KEY *key, int *length)

void ecb_ encrypt(const unsigned char *in, unsigned char *out,

long length, const KEY *key, unsigned char *iv, int enc)

{/* 电子密码本: Electronic Code Book */

register int i;

int len = 8;

register long l = length;

unsigned char buf[8];

if(enc)/*encryption*/

{

for(i=0;i<=l;i+=8)

{

encrypt(&in[i], &out[i], key, &len);/*len == 8 will always be true here*/

}

else

{

for(i=0;i<=l;i+=8)

{

decrypt(&in[i], &out[i], key, &len);/*len == 8 will always be true here*/

}

}

}

void cbc_encrypt(const unsigned char *in, unsigned char *out,

long length, const KEY *key, unsigned char *iv, int enc)

{/* 密钥分组连接模式 */

register int i;

int len = 8;

register long l = length;

unsigned char buf[8];

if(enc)/*encryption*/

{

for(l-=8; l>=0; l-=8, in+=8, out+=8)

{

for(i=0; i<8;>

buf[i] = in[i] ^ iv[i];

encrypt(buf, iv, key, &len);/*len == 8 will always be true here*/

for(i=0; i<8;>

out[i] = iv[i];

}

/*final block*/

if(l != -8)

{

for(i=0; i

buf[i] = in[i] ^ iv[i];

for(; i<8;>

buf[i] = iv[i];

encrypt(buf, iv, key, &len);/*len == 8 here*/

for(i=0; i<8;>

out[i] = iv[i];

}

/* 加密输出为做下一次得iv ,iv与in异或运算的结果作为加密输入*/

}

else/*decryption*/

{

for(l-=8; l>=0; l-=8, in+=8, out +=8)

{

decrypt(in, buf, key, &len);

for(i=0; i<8;>

out[i] = buf[i] ^ iv[i];