Initialize ctx for decryption with an optional ENGINE implementation.
Declared in <openssl/evp.h>
int
EVP_DecryptInit_ex(
EVP_CIPHER_CTX* ctx,
EVP_CIPHER const* cipher,
ENGINE* impl,
unsigned char const* key,
unsigned char const* iv);
1 on success, or 0 on failure.
| Name | Description |
|---|---|
| ctx | Cipher context to initialize. |
| cipher | Cipher algorithm, or NULL to reuse the current algorithm. |
| impl | Optional ENGINE providing the implementation, or NULL. |
| key | Decryption key bytes, or NULL to set later. |
| iv | Initialization vector, or NULL when not required / set later. |