Opt-In Software

Contacts

Programs

• Email List Manager
• Proxy Checker
• Thumbnail Grabber
• Web Searcher
• YouTube Flash Grabber

Online Tools

• Your IP Address

Proxylists

• Elite Proxy
• Anonymous Proxy
• Transparent Proxy
• HTTPS Proxy
• SOCKS 4/5
• Reverse Proxy
• Proxy Sites

Opt-In Mail

Opt-In Mail is a small application to send e-mail. You don't need to use your provider's SMTP server because Opt-In Mail sends e-mail directly.

The key feature of the program is an ability to sign your message using Yahoo! DomainKeys technology. Opt-In Mail adds a header named "DomainKey-Signature" that contains a digital signature of the contents of the e-mail. The DomainKeys-enabled receiving email system extract this signature and claimed From: domain from the email headers, fetches the public key from DNS for this domain and verifies that the signature was generated by the matching private key.

1. First of all you need a public/private key pair to use for signing e-mail.
   You can use this openssl command to generate a 512 bit private key:
   
   $ openssl genrsa -out rsa.private 512
   
   To extract the public key component from private key, use openssl like this:
   
   $ openssl rsa -in rsa.private -out rsa.public -pubout -outform PEM
   
   Read more details how to generate a DomainKey public/private key-pair here.
    
2. Save the private key to the file on your disk and enter the path to it in "Private Key File" field in Opt-In Mail.
3. Pick a selector name (e.g. "s1"). Enter it in "Selector" field in Opt-In Mail.
4. Put the public key data in DNS, in your domain, using the selector name you picked. Your public key file should contain lines like this:
   
   -----BEGIN PUBLIC KEY-----
   MHwwDQYJKoZIhvcNAQEBBQADawAwaAJhALHOmM8.....4AA
   /vQrcgpbdhCPLlT/AVDedXH/dBU1CDiVVt+3XnY65TAIEFI...wq0/
   L7c2UfU+jZ3FaXKKWYdztHWF...QAB
   -----END PUBLIC KEY-----
   
   Take the contents of the public key without PEM header and footer, concatenate the lines together and create a TXT entry like this:
   
   s1._domainkey  IN TXT "k=rsa; t=y; p=MHwwDQJKo...QAB"
   
5. Choose Canonicalization algorithm - the method by which the headers and contents are prepared for presentation to the signing algorithm.
   Opt-In Mail supports "simple" and "nofws" values.

Download Opt-In Mail now

See also

• Yahoo! Anti-Spam Resource Center - DomainKeys
• DomainKeys - Wikipedia, the free encyclopedia
• DomainKey Library and Implementor's Tools