EVP_CIPHER_CTX_get_original_iv.3ossl - Man Page

Routines to inspect EVP_CIPHER_CTX IV data

Synopsis

 #include <openssl/evp.h>

 int EVP_CIPHER_CTX_get_original_iv(EVP_CIPHER_CTX *ctx, void *buf, size_t len);
 int EVP_CIPHER_CTX_get_updated_iv(EVP_CIPHER_CTX *ctx, void *buf, size_t len);

The following functions have been deprecated since OpenSSL 3.0, and can be hidden entirely by defining OPENSSL_API_COMPAT with a suitable version value, see openssl_user_macros(7):

 const unsigned char *EVP_CIPHER_CTX_iv(const EVP_CIPHER_CTX *ctx);
 const unsigned char *EVP_CIPHER_CTX_original_iv(const EVP_CIPHER_CTX *ctx);
 unsigned char *EVP_CIPHER_CTX_iv_noconst(EVP_CIPHER_CTX *ctx);

Description

EVP_CIPHER_CTX_get_original_iv() and EVP_CIPHER_CTX_get_updated_iv() copy initialization vector (IV) information from the EVP_CIPHER_CTX into the caller-supplied buffer. EVP_CIPHER_CTX_get_iv_length(3) can be used to determine an appropriate buffer size, and if the supplied buffer is too small, an error will be returned (and no data copied). EVP_CIPHER_CTX_get_original_iv() accesses the (“original”) IV that was supplied when the EVP_CIPHER_CTX was initialized, and EVP_CIPHER_CTX_get_updated_iv() accesses the current “IV state” of the cipher, which is updated during cipher operation for certain cipher modes (e.g., CBC and OFB).

The functions EVP_CIPHER_CTX_iv(), EVP_CIPHER_CTX_original_iv(), and EVP_CIPHER_CTX_iv_noconst() are deprecated functions that provide similar (at a conceptual level) functionality.  EVP_CIPHER_CTX_iv() returns a pointer to the beginning of the “IV state” as maintained internally in the EVP_CIPHER_CTX; EVP_CIPHER_CTX_original_iv() returns a pointer to the beginning of the (“original”) IV, as maintained by the EVP_CIPHER_CTX, that was provided when the EVP_CIPHER_CTX was initialized; and EVP_CIPHER_CTX_get_iv_noconst() is the same as EVP_CIPHER_CTX_iv() but has a different return type for the pointer.

Return Values

EVP_CIPHER_CTX_get_original_iv() and EVP_CIPHER_CTX_get_updated_iv() return 1 on success and 0 on failure.

The functions EVP_CIPHER_CTX_iv(), EVP_CIPHER_CTX_original_iv(), and EVP_CIPHER_CTX_iv_noconst() return a pointer to an IV as an array of bytes on success, and NULL on failure.

History

EVP_CIPHER_CTX_get_original_iv() and EVP_CIPHER_CTX_get_updated_iv() were added in OpenSSL 3.0.0.

EVP_CIPHER_CTX_iv(), EVP_CIPHER_CTX_original_iv(), and EVP_CIPHER_CTX_iv_noconst() were added in OpenSSL 1.1.0, and were deprecated in OpenSSL 3.0.0.

Referenced By

migration_guide.7ossl(7).

The man pages EVP_CIPHER_CTX_get_updated_iv.3ossl(3), EVP_CIPHER_CTX_iv.3ossl(3), EVP_CIPHER_CTX_iv_noconst.3ossl(3) and EVP_CIPHER_CTX_original_iv.3ossl(3) are aliases of EVP_CIPHER_CTX_get_original_iv.3ossl(3).

2022-09-12 3.0.5 OpenSSL