Base64(3) - phpMan

base64 (1)           - base64 encode/decode data and print to standard output
BIO_f_base64 (3ssl)  - base64 BIO filter
CTLOG_new_from_base64 (3ssl) - encapsulates information about a Certificate T...
MIME::Base64 (3pm)   - Encoding and decoding of base64 strings
SCT_new_from_base64 (3ssl) - A Certificate Transparency Signed Certificate Ti...