Predefined Constants
PHP Manual

Signature Algorithms

OPENSSL_ALGO_DSS1 (integer)
OPENSSL_ALGO_SHA1 (integer)
Used as default algorithm by openssl_sign() and openssl_verify().
OPENSSL_ALGO_MD5 (integer)
OPENSSL_ALGO_MD4 (integer)
OPENSSL_ALGO_MD2 (integer)

Note:

These constants were added in 5.0.0.


Predefined Constants
PHP Manual