[#CRYPTO_cts128_decrypt_block]
= CRYPTO_cts128_decrypt_block
:mrdocs:

Decrypt CS1 ciphertext stealing using a single‐block decrypt/encrypt pair via `block.`

== Synopsis

Declared in `<openssl/modes.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
size_t
CRYPTO_cts128_decrypt_block(
    unsigned char const* in,
    unsigned char* out,
    size_t len,
    void const* key,
    unsigned char ivec[],
    xref:block128_f.adoc[block128_f] block);
----

== Return Value

Number of plaintext bytes written, or 0 on error.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *in*
| Input ciphertext of length `len` (must be greater than 16).
| *out*
| Output plaintext buffer of length `len.`
| *len*
| Number of ciphertext bytes.
| *key*
| Cipher‐specific expanded key for `block.`
| *ivec*
| 16‐byte IV updated like CBC.
| *block*
| Block cipher function used by the CTS decrypt path.
|===


[.small]#Created with https://www.mrdocs.com[MrDocs]#