D2I_X509_NAME(3)

📦 version 4.4.0, in alpine 3.24, arch rolling

💖 NAME 💖

okay so bestie, this is D2I_X509_NAME(3) from libcrypto, and it's the manual page for decoding and encoding X.501 Name objects. The whole squad is d2i_X509_NAME, i2d_X509_NAME, X509_NAME_get0_der, X509_NAME_dup, X509_NAME_set, d2i_X509_NAME_ENTRY, i2d_X509_NAME_ENTRY, and X509_NAME_ENTRY_dup. periodt 💅

✨ SYNOPSIS ✨

library “libcrypto” #include <openssl/x509.h> — and here's the exact code, no cap:

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

X509_NAME *
d2i_X509_NAME(X509_NAME **val_out, const unsigned char **der_in,
    long length);

int
i2d_X509_NAME(X509_NAME *val_in, unsigned char **der_out);

int
X509_NAME_get0_der(X509_NAME *val_in, const unsigned char **der_out,
    size_t *out_len);

X509_NAME *
X509_NAME_dup(X509_NAME *val_in);

int
X509_NAME_set(X509_NAME **val_out, X509_NAME *val_in);

X509_NAME_ENTRY *
d2i_X509_NAME_ENTRY(X509_NAME_ENTRY **val_out,
    const unsigned char **der_in, long length);

int
i2d_X509_NAME_ENTRY(X509_NAME_ENTRY *val_in, unsigned char **der_out);

X509_NAME_ENTRY *
X509_NAME_ENTRY_dup(X509_NAME_ENTRY *val_in);

🌸 DESCRIPTION 🌸

These functions decode and encode X.501 Name objects using DER format. For the whole semantics, examples, caveats, and bugs situation, go see ASN1_item_d2i(3) — that's the reference bestie, iykyk.

d2i_X509_NAME() and i2d_X509_NAME() decode and encode an ASN.1 Name structure defined in RFC 5280 section 4.1.2.4. slay.

X509_NAME_get0_der() is a variant of i2d_X509_NAME() that does not copy the encoded output — instead it returns a pointer to the internally cached DER-encoded version of the name. Also, it does not return the length of the output in bytes, but instead stores it in out_len. If the cached encoded form happens to be out of date, both functions update it before copying it or returning a pointer to it. iconic behavior honestly.

X509_NAME_dup() copies val_in by calling i2d_X509_NAME() and d2i_X509_NAME().

X509_NAME_set() makes sure that *val_out contains the same data as val_in after the call, except that it fails if val_in is NULL. If *val_out is the same pointer as val_in, the function succeeds without changing anything. Otherwise, it copies val_in using X509_NAME_dup(), and in case of success, it frees *val_out and sets it to a pointer to the new object. When the function fails, it never changes anything. In any case, val_in remains valid and may or may not be the same pointer as *val_out after the call. no surprises, just precise little gremlin rules 💅

d2i_X509_NAME_ENTRY() and i2d_X509_NAME_ENTRY() decode and encode an ASN.1 RelativeDistinguishedName structure defined in RFC 5280 section 4.1.2.4.

X509_NAME_ENTRY_dup() copies val_in by calling i2d_X509_NAME_ENTRY() and d2i_X509_NAME_ENTRY().

🎀 RETURN VALUES 🎀

  • d2i_X509_NAME() and X509_NAME_dup() — return the new X509_NAME object or NULL if an error occurs.
  • X509_NAME_set() and X509_NAME_get0_der() — return 1 on success or 0 if an error occurs.
  • d2i_X509_NAME_ENTRY() and X509_NAME_ENTRY_dup() — return the new X509_NAME_ENTRY object or NULL if an error occurs.
  • i2d_X509_NAME() and i2d_X509_NAME_ENTRY() — return the number of bytes successfully encoded or a negative value if an error occurs.

🦋 SEE ALSO 🦋

go read these next bestie, the lore is real 🫶

🌈 STANDARDS 🌈

  • RFC 5280: Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile
  • ITU-T Recommendation X.690, also known as ISO/IEC 8825-1: Information technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER).

👑 HISTORY 👑

  • X509_NAME_dup() first appeared in SSLeay 0.4.4.
  • d2i_X509_NAME(), i2d_X509_NAME(), d2i_X509_NAME_ENTRY(), i2d_X509_NAME_ENTRY(), and X509_NAME_ENTRY_dup() first appeared in SSLeay 0.5.1.
  • X509_NAME_set() first appeared in SSLeay 0.8.0.
  • These functions have been available since OpenBSD 2.4.
  • X509_NAME_get0_der() first appeared in OpenSSL 1.1.0 and has been available since OpenBSD 6.3.

and that's the whole page, bestie — D2I_X509_NAME(3) from Debian, dated June 8, 2025, signing off with a lil kiss 💋✨

📦 where this page comes from