RSA_sign_ASN1_OCTET_STRING(3)

RSA_sign_ASN1_OCTET_STRING(3) | OpenSSL | RSA_sign_ASN1_OCTET_STRING(3)

# NAME

RSA_sign_ASN1_OCTET_STRING, RSA_verify_ASN1_OCTET_STRING - RSA signatures

# SYNOPSIS

     #include <openssl/rsa.h>

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):

     int RSA_sign_ASN1_OCTET_STRING(int dummy, unsigned char *m,
                                    unsigned int m_len, unsigned char *sigret,
                                    unsigned int *siglen, RSA *rsa);
     int RSA_verify_ASN1_OCTET_STRING(int dummy, unsigned char *m,
                                      unsigned int m_len, unsigned char *sigbuf,
                                      unsigned int siglen, RSA *rsa);

# DESCRIPTION

All of the functions described on this page are deprecated. Applications should instead use EVP PKEY APIs.

RSA_sign_ASN1_OCTET_STRING() signs the octet string m of size m_len using the private key rsa represented in DER using PKCS #1 padding. It stores the signature in sigret and the signature size in siglen. sigret must point to RSA_size(rsa) bytes of memory.

dummy is ignored.

The random number generator must be seeded when calling RSA_sign_ASN1_OCTET_STRING(). If the automatic seeding or reseeding of the OpenSSL CSPRNG fails due to external circumstances (see RAND(7)), the operation will fail.

RSA_verify_ASN1_OCTET_STRING() verifies that the signature sigbuf of size siglen is the DER representation of a given octet string m of size m_len. dummy is ignored. rsa is the signer's public key.

# RETURN VALUES

RSA_sign_ASN1_OCTET_STRING() returns 1 on success, 0 otherwise. RSA_verify_ASN1_OCTET_STRING() returns 1 on successful verification, 0 otherwise.

The error codes can be obtained by ERR_get_error(3).

# BUGS

These functions serve no recognizable purpose.

# SEE ALSO

ERR_get_error(3), RAND_bytes(3), RSA_sign(3), RSA_verify(3), RAND(7)

# HISTORY

All of these functions were deprecated in OpenSSL 3.0.

# COPYRIGHT

Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.

2026-06-09 | 3.5.7