在C中为RSA解密的OpenSSL EVP api的EVP_OpenInit()中出错。

I am facing a problem in RSA decryption using OpenSSL Library (EVP api). Here is my code for key generation

我使用OpenSSL库(EVP api)面对RSA解密的问题。这是我的密钥生成代码。

#include <stdio.h>
#include <openssl/evp.h>
#include <openssl/rsa.h>
#include <openssl/bio.h>
#include <openssl/pem.h>

#define SECFILE "sec.pem"
#define PUBFILE "pub.pem"

int main()
{

    EVP_PKEY_CTX *ctx;
    EVP_PKEY *pkey = NULL;
    ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_RSA, NULL);
    FILE *fp;

    if (!ctx)
    {
        /* Error occurred */
        perror("Error in CTX \n");

    }
    if (EVP_PKEY_keygen_init(ctx) <= 0)
    {
        /* Error */
        perror("Error in EVP_PKEY_keygen_init \n");
    }
    if (EVP_PKEY_CTX_set_rsa_keygen_bits(ctx, 2048) <= 0)
    {
        /* Error */
        perror("Error in EVP_PKEY_CTX_set_rsa_keygen_bits \n");
    }
    /* Generate key */
    if (EVP_PKEY_keygen(ctx, &pkey) <= 0)
    {   
        /* Error */
        perror("Error in EVP_PKEY_keygen \n");

    }


    fp = fopen(SECFILE, "w");
    PEM_write_PrivateKey(fp, pkey, NULL,NULL, 0,0, NULL);
    fclose(fp);

    fp = fopen(PUBFILE, "w");
    PEM_write_PUBKEY(fp,pkey);
    fclose(fp);


    return 0;
}

For encryption :

加密:

I used this link

我使用这个链接

For decryption :

解密:

   int do_evp_open(FILE *rsa_pkey_file, FILE *in_file, FILE *out_file) 
{ 
    int retval = 0; 
    RSA *rsa_pkey = NULL; 
    EVP_PKEY *pkey = EVP_PKEY_new(); 
    EVP_CIPHER_CTX ctx; 
    unsigned char buffer[4096]; 
    unsigned char buffer_out[4096 + EVP_MAX_IV_LENGTH]; 
    size_t len; 
    int len_out; 
    unsigned char *ek; 
    int eklen ; 
    uint32_t eklen_n; 
    unsigned char iv[EVP_MAX_IV_LENGTH] = {122,205,106,192,4,183,69,176,84,28,214,226,220,140,86,174}; 


    /// Read RSA Private Key 
    if (PEM_read_RSAPrivateKey(rsa_pkey_file, &rsa_pkey, NULL, NULL) == NULL) 
    { 
        fprintf(stderr, "Error loading RSA Private Key File.\n"); 
        ERR_print_errors_fp(stderr); 
        retval = -2; 
        goto out; 
    } 


    /// Assign RSA key to EVP key
    if (!EVP_PKEY_assign_RSA(pkey, rsa_pkey)) 
    { 
        fprintf(stderr, "EVP_PKEY_assign_RSA: failed.\n"); 
        retval = -3; 
        goto out; 
    }

    EVP_CIPHER_CTX_init(&ctx); 

    ek = malloc( EVP_PKEY_size(pkey)); 



    if (!EVP_OpenInit(&ctx, EVP_aes_128_cbc(), ek, eklen, iv,pkey)) 
    { 
        fprintf(stderr, "EVP_OpenInit: failed.\n"); 
       ERR_print_errors_fp(stderr); /// Prints error of occured in Openssl  
        retval = -3; 
        goto out_free; 
    } 




    while ((len = fread(buffer, 1, sizeof buffer, in_file)) > 0) 
    { 
        if (!EVP_OpenUpdate(&ctx, buffer_out, &len_out, buffer, len)) 
        { 
            fprintf(stderr, "EVP_OpenUpdate: failed.\n"); 
            retval = 3; 
            goto out_free; 
        } 

        if (fwrite(buffer_out, len_out, 1, out_file) != 1) 
        { 
            perror("output file"); 
            retval = -5; 
            goto out_free; 
        } 
    } 

    if (ferror(in_file)) 
    { 
        perror("input file"); 
        retval = -4; 
        goto out_free; 
    } 

    if (!EVP_OpenFinal(&ctx, buffer_out, &len_out)) 
    { 
        fprintf(stderr, "EVP_OpenFinal: failed.\n"); 
        retval = - 3; 
        goto out_free; 
    } 

    if (fwrite(buffer_out, len_out, 1, out_file) != 1) 
    { 
        perror("output file"); 
        retval = -5; 
        goto out_free; 
    } 

    out_free: 
    EVP_PKEY_free(pkey); 
    free(ek); 

    out: 
    return retval; 
}

My Private and public keys are :

我的私钥和公钥是:

The error I am getting While EVP_OpenInit is :

EVP_OpenInit的错误是:

140004942804648:error:0407106B:lib(4):func(113):reason(107):rsa_pk1.c:190: 140004942804648:error:04065072:lib(4):func(101):reason(114):rsa_eay.c:594

140004942804648:错误:140004942804648 b:*(4):func(113):原因(107):rsa_pk1。c:190:190:错误:190:*(4):func(101):原因(114):rsa_eay.c:594

Any help would be appreciated. Thanks, Pawan

如有任何帮助，我们将不胜感激。谢谢你,一生

2 个解决方案

#1

Are you absolutely sure, that you have initialized variable eklen?

你确定你已经初始化了变量eklen吗?

#2

I see you have used EVP_OpenInit(), EVP_OpenUpdate() and EVP_OpenFinal() for decryption. So I'm going to assume that you've used EVP_SealInit(), EVP_SealUpdate() and EVP_SealFinal() functions for encryption.

我看到您使用了EVP_OpenInit()、EVP_OpenUpdate()和EVP_OpenFinal()来进行解密。因此，我将假设您使用了EVP_SealInit()、EVP_SealUpdate()和EVP_SealFinal()函数来进行加密。

So if you have used EVP_SealInit(), you must have passed the address (pointer) to eklen (please check man EVP_SealInit) where the variable gets a value assigned. In analogous to that the eklen variable that you are passing to EVP_OpenInit() must contain a valid key length.

因此，如果您使用EVP_SealInit()，那么您必须将地址(指针)传递给eklen(请检查man EVP_SealInit)，其中变量将获得指定的值。在类似的情况下，您传递给EVP_OpenInit()的eklen变量必须包含一个有效的密钥长度。

The following is the description from man EVP_OpenInit.

下面是man EVP_OpenInit的描述。

EVP_OpenInit() initializes a cipher context ctx for decryption with cipher type. It decrypts the encrypted symmetric key of length ekl bytes passed in the ek parameter using the private key priv. The IV is supplied in the iv parameter.

EVP_OpenInit()初始化一个cipher上下文ctx，以使用cipher类型进行解密。它使用私钥priv来解密在ek参数中传递的长度ekl字节的加密的对称密钥。IV是在IV参数中提供的。

I'm not sure here, but I guess you need to use EVP_PKEY_size() function in this case to get the length of the key.

这里我不确定，但是我猜您需要在这个例子中使用EVP_PKEY_size()函数来获得密钥的长度。

For example (in your decryption code):

例如(在您的解密代码中):

....
..
. 
EVP_CIPHER_CTX_init(&ctx); 
ek = malloc( EVP_PKEY_size(pkey)); 

/* Add the following line */
eklen = EVP_PKEY_size(pkey);

if (!EVP_OpenInit(&ctx, EVP_aes_128_cbc(), ek, eklen, iv,pkey)) 
{ 
    fprintf(stderr, "EVP_OpenInit: failed.\n"); 
...
..
.

#1