> I think part of my problem is that EVP_BytesToKey only returns a 16 byte key. You will probably need to duplicate Crypt-CBC-2.30's algorithm for creating or deriving the key. Blowfish uses a variable length key (some hand waiving) [1], so there should be no algorithm to duplicate. Use the 56 bytes directly.
If I'm wrong about Blowfish or the way Crypt-CBC-2.30 works, then my apologies. I don't use either of them. Jeff [1] http://www.schneier.com/blowfish.html On Thu, Sep 16, 2010 at 5:35 PM, Eric Nichols (DirWiz) <e...@dirwiz.com> wrote: > 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; > } > ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager majord...@openssl.org
