From CommuniCrypt Software:
CommuniCrypt Mail is an all-in-one solution to protect your Email privacy with the strongest encryption available. Encryption/decryption is optional to enable/disable. CommuniCrypt Mail now collects all your e-mails from up to 6 POP3 accounts. With the integrated file/attachment encryption/decryption tool you can encrypt or decrypt your mail attachments or all other files you like with RSA or with AES Rijndael (256 bit) encryption. Version 1.14 added integrated file encryption/decryption tool (RSA or AES Rijndael 256 bit);possibility to encrypt outgoing attachments (RSA or AES Rijndael 256 bit); possibility to decrypt received attachment after saving them; some internal improvements.