ASN1_INTEGER_GET_INT64(3SSL)

📦
version 4.0.3 · 14 versions
, in ubuntu stonking

💖 ASN1_INTEGER_GET_INT64 💖

okay bestie, grab your iced coffee because we're doing the ASN.1 integer glow-up ✨ this is the 3SSL manual page, part of the OpenSSL family, and it's literally just "how do I turn these fancy DER integers into normal C numbers and back again" 💅

🌸 NAME 🌸

ASN1_INTEGER_get_uint64, ASN1_INTEGER_set_uint64, ASN1_INTEGER_get_int64, ASN1_INTEGER_get, ASN1_INTEGER_set_int64, ASN1_INTEGER_set, BN_to_ASN1_INTEGER, ASN1_INTEGER_to_BN, ASN1_ENUMERATED_get_int64, ASN1_ENUMERATED_get, ASN1_ENUMERATED_set_int64, ASN1_ENUMERATED_set, BN_to_ASN1_ENUMERATED, ASN1_ENUMERATED_to_BN — they're all the ASN.1 INTEGER and ENUMERATED utilities 🎀

✨ SYNOPSIS ✨

#include <openssl/asn1.h>

int ASN1_INTEGER_get_int64(int64_t *pr, const ASN1_INTEGER *a);
long ASN1_INTEGER_get(const ASN1_INTEGER *a);

int ASN1_INTEGER_set_int64(ASN1_INTEGER *a, int64_t r);
int ASN1_INTEGER_set(ASN1_INTEGER *a, long v);

int ASN1_INTEGER_get_uint64(uint64_t *pr, const ASN1_INTEGER *a);
int ASN1_INTEGER_set_uint64(ASN1_INTEGER *a, uint64_t r);

ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai);
BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn);

int ASN1_ENUMERATED_get_int64(int64_t *pr, const ASN1_ENUMERATED *a);
long ASN1_ENUMERATED_get(const ASN1_ENUMERATED *a);

int ASN1_ENUMERATED_set_int64(ASN1_ENUMERATED *a, int64_t r);
int ASN1_ENUMERATED_set(ASN1_ENUMERATED *a, long v);

ASN1_ENUMERATED *BN_to_ASN1_ENUMERATED(const BIGNUM *bn, ASN1_ENUMERATED *ai);
BIGNUM *ASN1_ENUMERATED_to_BN(const ASN1_ENUMERATED *ai, BIGNUM *bn);
🫶 ngl, that's a LOT of functions, but they come in cute matched pairs — getters on the left, setters on the right, and the BIGNUM ones doing the big-number shuffle.

💜 DESCRIPTION 💜

so basically, all of these convert to and from ASN1_INTEGER and ASN1_ENUMERATED structures. that's the whole vibe. 💫

ASN1_INTEGER_get_int64() converts an ASN1_INTEGER into an int64_t type. If successful it returns 1 and sets *pr to the value of a. If it fails (due to invalid type or the value being too big to fit into an int64_t type) it returns 0.

ASN1_INTEGER_get_uint64() is similar to ASN1_INTEGER_get_int64_t() except it converts to a uint64_t type and an error is returned if the passed integer is negative.

ASN1_INTEGER_get() also returns the value of a but it returns 0 if a is NULL and -1 on error (which is ambiguous because -1 is a legitimate value for an ASN1_INTEGER). New applications should use ASN1_INTEGER_get_int64() instead. 🙈 yes that ambiguity is giving red flag energy, we'll get to it.

ASN1_INTEGER_set_int64() sets the value of ASN1_INTEGER a to the int64_t value r.

ASN1_INTEGER_set_uint64() sets the value of ASN1_INTEGER a to the uint64_t value r.

ASN1_INTEGER_set() sets the value of ASN1_INTEGER a to the long value v.

BN_to_ASN1_INTEGER() converts BIGNUM bn to an ASN1_INTEGER. If ai is NULL a new ASN1_INTEGER structure is returned. If ai is not NULL then the existing structure will be used instead. (reuse queen 👑)

ASN1_INTEGER_to_BN() converts ASN1_INTEGER ai into a BIGNUM. If bn is NULL a new BIGNUM structure is returned. If bn is not NULL then the existing structure will be used instead.

ASN1_ENUMERATED_get_int64(), ASN1_ENUMERATED_set_int64(), ASN1_ENUMERATED_set(), BN_to_ASN1_ENUMERATED() and ASN1_ENUMERATED_to_BN() behave in an identical way to their ASN1_INTEGER counterparts except they operate on an ASN1_ENUMERATED value. 🦋 twinning fr fr.

ASN1_ENUMERATED_get() returns the value of a in a similar way to ASN1_INTEGER_get() but it returns 0xffffffffL if the value of a will not fit in a long type. New applications should use ASN1_ENUMERATED_get_int64() instead.

🌈 NOTES 🌈

in general an ASN1_INTEGER or ASN1_ENUMERATED type can contain an integer of almost arbitrary size and so cannot always be represented by a C int64_t type. 😭 like, it's big. it contains multitudes.

however, in many cases (for example version numbers) they represent small integers which can be more easily manipulated if converted to an appropriate C integer type. so for the little baby numbers, you're totally fine. 💖

💀 BUGS 💀

the ambiguous return values of ASN1_INTEGER_get() and ASN1_ENUMERATED_get() mean these functions should be avoided if possible. they are retained for compatibility. normally the ambiguous return values are not legitimate values for the fields they represent.

🚨 bestie listen to me: if there is an "avoid this" note in a manpage, you avoid it. it's giving deprecated-for-a-reason.

⭐ RETURN VALUES ⭐

ASN1_INTEGER_set_int64(), ASN1_INTEGER_set(), ASN1_ENUMERATED_set_int64() and ASN1_ENUMERATED_set() return 1 for success and 0 for failure. They will only fail if a memory allocation error occurs.

ASN1_INTEGER_get_int64() and ASN1_ENUMERATED_get_int64() return 1 for success and 0 for failure. They will fail if the passed type is incorrect (this will only happen if there is a programming error) or if the value exceeds the range of an int64_t type.

BN_to_ASN1_INTEGER() and BN_to_ASN1_ENUMERATED() return an ASN1_INTEGER or ASN1_ENUMERATED structure respectively or NULL if an error occurs. They will only fail due to a memory allocation error.

ASN1_INTEGER_to_BN() and ASN1_ENUMERATED_to_BN() return a BIGNUM structure or NULL if an error occurs. They can fail if the passed type is incorrect (due to programming error) or due to a memory allocation failure.

🔥 SEE ALSO 🔥

(iykyk — that's where you go to find out why it returned 0 💅)

🎀 HISTORY 🎀

ASN1_INTEGER_set_int64(), ASN1_INTEGER_get_int64(), ASN1_ENUMERATED_set_int64() and ASN1_ENUMERATED_get_int64() were added in OpenSSL 1.1.0.

Copyright 2015-2026 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>.

okay slay, that's the whole page 🌸 these are the ASN.1 INTEGER and ENUMERATED utilities, documented for OpenSSL 4.0.3, dated 2026-09-29, in the 3SSL manual section. go forth and convert responsibly, bestie — and remember, big numbers go to BIGNUM, small numbers go to int64_t, and ambiguous return values go in the bin 💖✨🫶

📦 where this page comes from