> From: owner-openssl-us...@openssl.org On Behalf Of Damir Musulin > Sent: Wednesday, 22 June, 2011 08:46
> I'm brand new to programming against OpenSSL (EVP) > so if i make any stupid mistake I'm sorry in advance. > This is really a C programming issue, not OpenSSL (or EVP). > I use the blowfish algorithm from the OpenSSL page to encrypt > a string in C. > to code is from: > http://www.openssl.org/docs/crypto/EVP_EncryptInit.html > > I have created a decrypt function and it fails (how wonderful) > > The problem lies in the EVP_DecryptFinal_ex. It is *reported* there but actually occurred earlier. > I have made use of the ERR_print_errors_fp(stderr); option to see what > is wrong but it is quite > a cryptic message: > 2621:error:0606506D:lib(6):func(101):reason(109):evp_enc.c:323: > As already answered or equivalently http://www.openssl.org/support/faq.html#PROG7 > What i can find on the internet is that it is a wrong lenght > block or i > need extra padding. For decrypt it's wrong length, period. Padding is added on the *encrypt* side. If you use the lower level routines you may need to do this yourself (depending on your mode and data) but EVP normally handles it automatically. <snip> > EVP_EncryptInit_ex(&ctx, EVP_bf_cbc(), NULL, key, iv); > > if(!EVP_EncryptUpdate(&ctx, outbuf, &outlen, intext, <snip> > if(!EVP_EncryptFinal_ex(&ctx, outbuf + outlen, &tmplen)) <snip> > EVP_CIPHER_CTX_cleanup(&ctx); > /* Need binary mode for fopen because encrypted data is > * binary data. Also cannot use strlen() on it because > * it wont be null terminated and may contain embedded > * nulls. > */ You copied this comment correctly but apparently ignored it. Ciphertext (for modern ciphers) is NOT a C string, and cannot safely be manipulated as a C string, as your code tries to. Use the actual length of the ciphertext, not strlen(). ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager majord...@openssl.org
