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X509_sign(3)                        OpenSSL                       X509_sign(3)

       X509_sign, X509_sign_ctx, X509_verify, X509_REQ_sign,
       X509_REQ_sign_ctx, X509_REQ_verify, X509_CRL_sign, X509_CRL_sign_ctx,
       X509_CRL_verify - sign or verify certificate, certificate request or
       CRL signature

       libcrypto, -lcrypto

        #include <openssl/x509.h>

        int X509_sign(X509 *x, EVP_PKEY *pkey, const EVP_MD *md);
        int X509_sign_ctx(X509 *x, EVP_MD_CTX *ctx);
        int X509_verify(X509 *a, EVP_PKEY *r);

        int X509_REQ_sign(X509_REQ *x, EVP_PKEY *pkey, const EVP_MD *md);
        int X509_REQ_sign_ctx(X509_REQ *x, EVP_MD_CTX *ctx);
        int X509_REQ_verify(X509_REQ *a, EVP_PKEY *r);

        int X509_CRL_sign(X509_CRL *x, EVP_PKEY *pkey, const EVP_MD *md);
        int X509_CRL_sign_ctx(X509_CRL *x, EVP_MD_CTX *ctx);
        int X509_CRL_verify(X509_CRL *a, EVP_PKEY *r);

       X509_sign() signs certificate x using private key pkey and message
       digest md and sets the signature in x. X509_sign_ctx() also signs
       certificate x but uses the parameters contained in digest context ctx.

       X509_verify() verifies the signature of certificate x using public key
       pkey. Only the signature is checked: no other checks (such as
       certificate chain validity) are performed.

       X509_REQ_sign(), X509_REQ_sign_ctx(), X509_REQ_verify(),
       X509_CRL_sign(), X509_CRL_sign_ctx() and X509_CRL_verify() sign and
       verify certificate requests and CRLs respectively.

       X509_sign_ctx() is used where the default parameters for the
       corresponding public key and digest are not suitable. It can be used to
       sign keys using RSA-PSS for example.

       For efficiency reasons and to work around ASN.1 encoding issues the
       encoding of the signed portion of a certificate, certificate request
       and CRL is cached internally. If the signed portion of the structure is
       modified the encoding is not always updated meaning a stale version is
       sometimes used. This is not normally a problem because modifying the
       signed portion will invalidate the signature and signing will always
       update the encoding.

       X509_sign(), X509_sign_ctx(), X509_REQ_sign(), X509_REQ_sign_ctx(),
       X509_CRL_sign() and X509_CRL_sign_ctx() return the size of the
       signature in bytes for success and zero for failure.

       X509_verify(), X509_REQ_verify() and X509_CRL_verify() return 1 if the
       signature is valid and 0 if the signature check fails. If the signature
       could not be checked at all because it was invalid or some other error
       occurred then -1 is returned.

       d2i_X509(3), ERR_get_error(3), X509_CRL_get0_by_serial(3),
       X509_get0_signature(3), X509_get_ext_d2i(3),
       X509_get_extension_flags(3), X509_get_pubkey(3),
       X509_get_subject_name(3), X509_get_version(3),
       X509_NAME_add_entry_by_txt(3), X509_NAME_ENTRY_get_object(3),
       X509_NAME_get_index_by_NID(3), X509_NAME_print_ex(3), X509_new(3),
       X509V3_get_d2i(3), X509_verify_cert(3)

       The X509_sign(), X509_REQ_sign() and X509_CRL_sign() functions are
       available in all versions of OpenSSL.

       The X509_sign_ctx(), X509_REQ_sign_ctx() and X509_CRL_sign_ctx()
       functions were added OpenSSL 1.0.1.

       Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (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

1.1.1i                            2019-03-12                      X509_sign(3)