openssl genrsa -out private.key 1024
openssl rsa -in private.key -pubout -out public.key
BIO
*
key
=
NULL;
RSA
*
r
=
NULL;
key
=
BIO_new(BIO_s_file());
BIO_read_filename(key,
"
c:\\private.key
"
);
r
=
PEM_read_bio_RSAPrivateKey(key, NULL, NULL, NULL);
BIO_free_all(key);
读取 private key 读取正常，r 并不返回空
使用同样方法读取 public key
BIO *key = NULL;
RSA *r = NULL;
key = BIO_new(BIO_s_file());
BIO_read_filename(key, "c:\\public.key");
r = PEM_read_bio_RSAPublicKey(key, NULL, NULL, NULL);
BIO_free_all(key);
不正常, r 总是返回 NULL，很不爽，将函数改一下 PEM_read_bio_RSA_PUBKEY
BIO *key1=NULL;
RSA *r1=NULL;
key1=BIO_new(BIO_s_file());
if(BIO_read_filename(key1,"c:\\public.key") <= 0 )
{
printf("error\n");
}
r1 = PEM_read_bio_RSA_PUBKEY(key1, NULL,NULL,NULL);
BIO_free_all(key1);
openssl_to_keys(r, 1024, priv, pub);
r1 读取成功
具体原因未知
作者: playmud 时间: 2009-08-24 11:53:00
让我们先来看一下pem.h头文件中的定义：
#define PEM_read_RSAPrivateKey(fp,x,cb,u) (RSA *)PEM_ASN1_read( \
(char *(*)())d2i_RSAPrivateKey,PEM_STRING_RSA,fp,(char **)x,cb,u)
#define PEM_read_RSAPublicKey(fp,x,cb,u) (RSA *)PEM_ASN1_read( \
(char *(*)())d2i_RSAPublicKey,PEM_STRING_RSA_PUBLIC,fp,(char **)x,cb,u)
#define PEM_read_bio_RSAPrivateKey(bp,x,cb,u) (RSA *)PEM_ASN1_read_bio( \
(char *(*)())d2i_RSAPrivateKey,PEM_STRING_RSA,bp,(char **)x,cb,u)
#define PEM_read_bio_RSAPublicKey(bp,x,cb,u) (RSA *)PEM_ASN1_read_bio( \
(char *(*)())d2i_RSAPublicKey,PEM_STRING_RSA_PUBLIC,bp,(char **)x,cb,u)
对应的很工整是不是，你生成一个私钥，然后用它生成一个公钥。
openssl genrsa -out private.pem 1024
openssl rsa -in priv.pem -pubout -out public.pem
用任何一种方法打开私钥，读取私钥信息，得到RSA，查看RSA，ok，没有问题，一切都还看起来比较正常。
然后用任何一种方法打开公钥，读取公钥信息，问题出现了:RSA对象为空，你失败了。
通过openssl的手册和帮助，你会发现两个函数：
PEM_read_bio_RSA_PUBKEY()
PEM_read_RSA_PUBKEY()
他们才是你要找的对应的，而上面两个函数是从任何.h里面找不到的，但是他们的确是真实存在的符号连接，在对应的.o文件中用objdump可以查看到他们的符号，很诡异！
现象描述完了，还未探其究竟。
附加读取 PEM file 的code
BIO *key = NULL;
RSA *r = NULL;
key = BIO_new(BIO_s_file());
BIO_read_filename(key, "c:\\private.key");
r = PEM_read_bio_RSAPrivateKey(key, NULL, NULL, NULL);
BIO_free_all(key);
R_RSA_PRIVATE_KEY priv;
R_RSA_PUBLIC_KEY pub;
openssl_to_keys(r, 1024, priv, pub);
BIO *key1=NULL;
RSA *r1=NULL;
key1=BIO_new(BIO_s_file());
if(BIO_read_filename(key1,"c:\\public.key") <= 0 )
{
printf("error\n");
}
r1 = PEM_read_bio_RSA_PUBKEY(key1, NULL,NULL,NULL);
BIO_free_all(key1);
openssl_to_keys(r, 1024, priv, pub);
static void bn_to_bin(BIGNUM* bn, unsigned char* bin, int n) {
memset(bin, 0, n);
int m = BN_num_bytes(bn);
BN_bn2bin(bn, bin+n-m);
}
void openssl_to_keys(
RSA* rp, int nbits, R_RSA_PRIVATE_KEY& priv, R_RSA_PUBLIC_KEY& pub
) {
pub.bits = nbits;
bn_to_bin(rp->n, pub.modulus, sizeof(pub.modulus));
bn_to_bin(rp->e, pub.exponent, sizeof(pub.exponent));
memset(&priv, 0, sizeof(priv));
priv.bits = nbits;
bn_to_bin(rp->n, priv.modulus, sizeof(priv.modulus));
bn_to_bin(rp->e, priv.publicExponent, sizeof(priv.publicExponent));
bn_to_bin(rp->d, priv.exponent, sizeof(priv.exponent));
bn_to_bin(rp->p, priv.prime[0], sizeof(priv.prime[0]));
bn_to_bin(rp->q, priv.prime[1], sizeof(priv.prime[1]));
bn_to_bin(rp->dmp1, priv.primeExponent[0], sizeof(priv.primeExponent[0]));
bn_to_bin(rp->dmq1, priv.primeExponent[1], sizeof(priv.primeExponent[1]));
bn_to_bin(rp->iqmp, priv.coefficient, sizeof(priv.coefficient));
}