EVP_BytesToKey Key length of 56?

[Eric Nichols (DirWiz)]

I am working with a legacy app and need to use OpenSSL to decrypt
Blowfish-cbc.  The library in question
(http://search.cpan.org/~lds/Crypt-CBC-2.30/CBC.pm) uses a 56 byte key size
while OpenSSL defaults to a 16 byte key size.

I think part of my problem is that EVP_BytesToKey only returns a 16 byte key.

Is there any way to change the key size to 56 bytes?  I've included my 16 byte
code below.

char *decrypt_bf(unsigned char *coded,int coded_len,unsigned char *keystr,int
keystr_len)
{
   //Make sure to #include <openssl/evp.h>
   //compile with -lcrypto if using gcc

   char buffer[1024];
   unsigned char key[16];
   unsigned char iv[8];
   unsigned char salt[8];
   int i;
   int plainlen;
   int finallen;

   memcpy(salt,coded+8,8);

   fprintf(stderr,"salt=");
   for (i=0; i<8; i++)
      fprintf(stderr,"%02X",salt[i]);
   fprintf(stderr,"\n");

   EVP_BytesToKey(EVP_bf_cbc(),EVP_md5(),salt,keystr,keystr_len,1,key,iv);

   EVP_CIPHER_CTX ctx;
   EVP_CIPHER_CTX_init(&ctx);

   EVP_DecryptInit(&ctx,EVP_bf_cbc(),key,iv);
   EVP_CIPHER_CTX_set_key_length(&ctx,16);

   fprintf(stderr,"IV=");
   for (i=0; i<8; i++)
      fprintf(stderr,"%02X",iv[i]);
   fprintf(stderr,"\n");

   fprintf(stderr,"KEY=");
   for (i=0; i<16; i++)
      fprintf(stderr,"%02X",key[i]);
   fprintf(stderr,"\n");

   EVP_DecryptInit(&ctx,NULL,key,NULL);
   EVP_DecryptUpdate(&ctx,buffer,&plainlen,coded+16,coded_len-16);
   EVP_DecryptFinal(&ctx,buffer+plainlen,&finallen);

   char *retval=(char *)malloc(finallen+1);
   retval[finallen]='\0';
   memcpy(retval,buffer,finallen);

   EVP_CIPHER_CTX_cleanup(&ctx);
   return retval;
}



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