Custom method functions removed from the OpenSSL Library

[Blog on OpenSSL Library]

Following on from the [removal of ENGINE code](https://openssl-
library.org/post/2025-12-18-remove-engines), deprecated [functions for
creating or modifying custom
METHODS](https://docs.openssl.org/master/man7/ossl-guide-migration/#engines-
and-method-apis) will be removed from OpenSSL 4.0.

## Summary

For a complete list of deprecated functions removed in OpenSSL 4.0, please see
the [ossl-removed-api](https://docs.openssl.org/master/man7/ossl-removed-
api/#openssl-40) documentation. They are divided into the following pull
requests:

* Custom ciphers methods (`EVP_CIPHER_meth_*`) were removed in [PR #29299](https://github.com/openssl/openssl/pull/29299).
* Custom message digest methods (`EVP_MD_meth_*`) were removed in [PR #29366](https://github.com/openssl/openssl/pull/29366).
* Custom private key methods (`EVP_PKEY_meth_*`) were removed in [PR #29384](https://github.com/openssl/openssl/pull/29384).
* Custom private key [Abstract Syntax Notation One](https://en.wikipedia.org/wiki/ASN.1) methods (`EVP_PKEY_asn1_*`) were removed in [PR #29405](https://github.com/openssl/openssl/pull/29405). (These functions were deprecated in OpenSSL 3.6.)

Instead of using these methods, developers are encouraged to use the [provider
framework](https://docs.openssl.org/master/man7/provider/).



URL: https://openssl-library.org/post/2026-02-03-remove-methods/