X509_REQ_ADD1_ATTR(3)

💅 NAME 💅

okay so bestie, welcome to X509_REQ_ADD1_ATTR(3) — the manual page for X.501 Attributes of PKCS#10 certification requests. It covers this whole squad: X509_REQ_add1_attr, X509_REQ_add1_attr_by_OBJ, X509_REQ_add1_attr_by_NID, X509_REQ_add1_attr_by_txt, X509_REQ_delete_attr, X509_REQ_get_attr, X509_REQ_get_attr_count, X509_REQ_get_attr_by_OBJ, and X509_REQ_get_attr_by_NID. Yes queen, that’s all of them. 💖

✨ SYNOPSIS ✨

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

int
X509_REQ_add1_attr(X509_REQ *req, X509_ATTRIBUTE *attr);

int
X509_REQ_add1_attr_by_OBJ(X509_REQ *req, const ASN1_OBJECT *obj,
    int type, const unsigned char *data, int len);

int
X509_REQ_add1_attr_by_NID(X509_REQ *req, int nid, int type,
    const unsigned char *data, int len);

int
X509_REQ_add1_attr_by_txt(X509_REQ *req, const char *name, int type,
    const unsigned char *data, int len);

X509_ATTRIBUTE *
X509_REQ_delete_attr(X509_REQ *req, int index);

X509_ATTRIBUTE *
X509_REQ_get_attr(const X509_REQ *req, int index);

int
X509_REQ_get_attr_count(const X509_REQ *req);

int
X509_REQ_get_attr_by_OBJ(const X509_REQ *req, const ASN1_OBJECT *obj,
    int start_after);

int
X509_REQ_get_attr_by_NID(const X509_REQ *req, int nid, int start_after);

🌸 DESCRIPTION 🌸

These functions support associating an array of X.501 Attributes with a PKCS#10 certification request. It’s giving “let’s attach some extra lore to this request” energy. 🎀

• X509_REQ_add1_attr() — appends a deep copy of attr, allocating a new array if necessary.
• X509_REQ_add1_attr_by_OBJ(), X509_REQ_add1_attr_by_NID(), and X509_REQ_add1_attr_by_txt() — create a new X.501 Attribute object using X509_ATTRIBUTE_create_by_OBJ(3), X509_ATTRIBUTE_create_by_NID(3), or X509_ATTRIBUTE_create_by_txt(3), respectively, allocating a new array if necessary.
• X509_REQ_delete_attr() — deletes the attribute with the zero-based index.
• X509_REQ_get_attr() — returns the attribute with the zero-based index.
• X509_REQ_get_attr_count() — returns the number of attributes currently associated with req.
• X509_REQ_get_attr_by_OBJ() and X509_REQ_get_attr_by_NID() — search for an attribute of the type obj or nid.

👑 RETURN VALUES 👑

• X509_REQ_add1_attr(), X509_REQ_add1_attr_by_OBJ(), X509_REQ_add1_attr_by_NID(), and X509_REQ_add1_attr_by_txt() — return 1 for success or 0 for failure.
• X509_REQ_delete_attr() and X509_REQ_get_attr() — return the deleted or requested attribute, or NULL if the requested index is negative or greater than or equal to the current number of attributes associated with req.
• X509_REQ_get_attr_count() — returns the current number of attributes.
• X509_REQ_get_attr_by_OBJ() and X509_REQ_get_attr_by_NID() — return the index of the first attribute that has an index greater than start_after and a type matching obj or nid, respectively, or -1 on failure. In addition, X509_REQ_get_attr_by_NID() returns -2 if OBJ_nid2obj(3) fails on the requested nid.

🦋 SEE ALSO 🦋

• OBJ_nid2obj(3)
• X509_ATTRIBUTE_create_by_OBJ(3)
• X509_ATTRIBUTE_new(3)
• X509_REQ_new(3)

🌈 HISTORY 🌈

These functions first appeared in OpenSSL 0.9.5 and have been available since OpenBSD 2.7. iconic behavior, honestly. ⭐

source vibe: Debian, dated June 8, 2025, for the X509_REQ_ADD1_ATTR(3) page — mwah 💅💖