Gets list of available curve names for ECC

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- PHP Manual
- OpenSSL Functions
- Gets list of available curve names for ECC

# openssl_get_curve_names

(PHP 7 >= 7.1.0, PHP 8)

openssl_get_curve_names — Gets list of available curve names for ECC

### Description

openssl_get_curve_names(): array|false

Gets the list of available curve names for use in Elliptic curve cryptography (ECC) for public/private key operations. The two most widely standardized/supported curves are prime256v1 (NIST P-256) and secp384r1 (NIST P-384).

Approximate Equivalancies of AES, RSA, DSA and ECC Keysizes
AES Symmetric Keysize (Bits) | RSA and DSA Keysize (Bits) | ECC Keysize (Bits)
--- | --- | ---
80 | 1024 | 160
112 | 2048 | 224
128 | 3072 | 256
192 | 7680 | 384
256 | 15360 | 512

» NIST recommends using ECC curves with at least 256 bits.

### Parameters

This function has no parameters.

### Return Values

An array of available curve names, or `false` on failure.

### Examples

Example #1 openssl_get_curve_names() example

    <?php
    $curve_names = openssl_get_curve_names();
    print_r($curve_names);
    ?>

The above example will output something similar to:

    Array
    (
        [0] => secp112r1
        [1] => secp112r2
        [2] => secp128r1
        [3] => secp128r2
        [4] => secp160k1
        [5] => secp160r1
        [6] => secp160r2
        [7] => secp192k1
        [8] => secp224k1
        [9] => secp224r1
        [10] => secp256k1
        [11] => secp384r1
        [12] => secp521r1
        [13] => prime192v1
        [14] => prime192v2
        [15] => prime192v3
        [16] => prime239v1
        [17] => prime239v2
        [18] => prime239v3
        [19] => prime256v1
        [20] => sect113r1
        [21] => sect113r2
        [22] => sect131r1
        [23] => sect131r2
        [24] => sect163k1
        [25] => sect163r1
        [26] => sect163r2
        [27] => sect193r1
        [28] => sect193r2
        [29] => sect233k1
        [30] => sect233r1
        [31] => sect239k1
        [32] => sect283k1
        [33] => sect283r1
        [34] => sect409k1
        [35] => sect409r1
        [36] => sect571k1
        [37] => sect571r1
        [38] => c2pnb163v1
        [39] => c2pnb163v2
        [40] => c2pnb163v3
        [41] => c2pnb176v1
        [42] => c2tnb191v1
        [43] => c2tnb191v2
        [44] => c2tnb191v3
        [45] => c2pnb208w1
        [46] => c2tnb239v1
        [47] => c2tnb239v2
        [48] => c2tnb239v3
        [49] => c2pnb272w1
        [50] => c2pnb304w1
        [51] => c2tnb359v1
        [52] => c2pnb368w1
        [53] => c2tnb431r1
        [54] => wap-wsg-idm-ecid-wtls1
        [55] => wap-wsg-idm-ecid-wtls3
        [56] => wap-wsg-idm-ecid-wtls4
        [57] => wap-wsg-idm-ecid-wtls5
        [58] => wap-wsg-idm-ecid-wtls6
        [59] => wap-wsg-idm-ecid-wtls7
        [60] => wap-wsg-idm-ecid-wtls8
        [61] => wap-wsg-idm-ecid-wtls9
        [62] => wap-wsg-idm-ecid-wtls10
        [63] => wap-wsg-idm-ecid-wtls11
        [64] => wap-wsg-idm-ecid-wtls12
        [65] => Oakley-EC2N-3
        [66] => Oakley-EC2N-4
        [67] => brainpoolP160r1
        [68] => brainpoolP160t1
        [69] => brainpoolP192r1
        [70] => brainpoolP192t1
        [71] => brainpoolP224r1
        [72] => brainpoolP224t1
        [73] => brainpoolP256r1
        [74] => brainpoolP256t1
        [75] => brainpoolP320r1
        [76] => brainpoolP320t1
        [77] => brainpoolP384r1
        [78] => brainpoolP384t1
        [79] => brainpoolP512r1
        [80] => brainpoolP512t1
    )