[openssl-users] BIO_seek() on bio_f_cipher with EVP_aes_256_ctr

[Dr. Stephen Henson]

On Thu, Aug 11, 2016, William King wrote:

> 
> 
> Does the BIO_seek() not handle incrementing or decrementing the IV
> counter? is there a callback that needs to be set to calculate what the
> IV counter value should be for a given file position for the cipher?
> 

Calling BIO_seek() on a chain of BIOs can have unpredictable results
especially if any buffer data or have internal state.

I'd suggest you use the cipher directly instead of through a cipher BIO.

Steve.
--
Dr Stephen N. Henson. OpenSSL project core developer.
Commercial tech support now available see: http://www.openssl.org