X509_VERIFY_CERT(3) | Library Functions Manual | X509_VERIFY_CERT(3)

# NAME

`X509_verify_cert` — discover and verify X509 certificate chain

# SYNOPSIS

library “libcrypto”
`#include <openssl/x509.h>`

int
`X509_verify_cert`(X509_STORE_CTX *ctx);

# DESCRIPTION

The `X509_verify_cert`() function attempts to discover and validate a certificate chain based on parameters in ctx.

Applications rarely call this function directly, but it is used by OpenSSL internally for certificate validation, in both the S/MIME and SSL/TLS code.

# RETURN VALUES

If a complete chain can be built and validated this function returns 1, otherwise it returns a value <= 0 indicating failure.

Additional error information can be obtained by examining ctx, using X509_STORE_CTX_get_error(3).

# SEE ALSO

openssl(1), X509_STORE_CTX_get_error(3), X509_STORE_CTX_new(3)

# HISTORY

`X509_verify_cert`() first appeared in SSLeay 0.8.0 and has been available since OpenBSD 2.4.

# BUGS

This function uses the header `<openssl/x509.h>` as opposed to most chain verification functions which use `<openssl/x509_vfy.h>`.

June 8, 2025 | Debian