rsac is software that performs encryption and digital signature using RSA public key cipher.

It supports keys of 512-bit, 1,024-bit and 2,048-bit long.
It does not support keys of 4,096-bit long.

As the encryption method, it supports PKCS#1 v.1.5 and RSA-KEM.

The digital signature uses PKCS#1 v.1.5 as a method.
The storage format is PKCS#7 SignedData.

You can use X.509 Public Key Certificate, PKCS#12 for encryption and creation (sign) and verification of digital signatures.

It can be used by any application that conforms to the standard specification.

It has a simple structure, but you can also create an X.509 public key certificate and PKCS#12.

rsac does not support DSS, DSA, ECDSA, and Elliptic Curve Cryptography etc. at all.

In addition, as auxiliary ones, random number split cipher, block cipher (AES-256-CBC), hash function, HMAC etc. are also implemented.