sha256(4) - phpMan

EVP_aes_128_cbc_hmac_sha256 (3ssl) - EVP AES cipher
EVP_aes_256_cbc_hmac_sha256 (3ssl) - EVP AES cipher
EVP_sha256 (3ssl)    - SHA-2 For EVP
Mail::DKIM::Algorithm::rsa_sha256 (3pm) - rsa sha256 algorithm class
SHA256 (3ssl)        - Secure Hash Algorithm
SHA256_Final (3ssl)  - Secure Hash Algorithm
SHA256_Init (3ssl)   - Secure Hash Algorithm
SHA256_Update (3ssl) - Secure Hash Algorithm
sha256sum (1)        - compute and check SHA256 message digest