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76 lines
3.3 KiB
Markdown
76 lines
3.3 KiB
Markdown
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# Mongoose SSL guide
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SSL is a protocol that makes web communication secure. To enable SSL
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in mongoose, 3 steps are required:
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1. Valid certificate file must be created
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2. `ssl_certificate` options must be set to contain path to the
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certificate file.
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3. `listening_ports` option must contain a port number with letter `s`
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appended to it, which instructs Mongoose to use SSL for all connections
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made to that port.
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Below is the `mongoose.conf` file snippet for typical SSL setup:
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document_root www_root # Serve files in www_root directory
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listening_ports 80r,443s # Redirect all HTTP requests to HTTPS
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ssl_certificate ssl_cert.pem # Location of certificate file
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## How to create SSL certificate file
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SSL certificate file is a text file that must contain at least two
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sections:
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1. A private key
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2. A certificate
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Both sections should be chunks of text in PEM format. When PEM file is
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opened in a text editor, it looks like this:
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-----BEGIN RSA PRIVATE KEY-----
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MIIEogIBAAKCAQEAwONaLOP7EdegqjRuQKSDXzvHmFMZfBufjhELhNjo5KsL4ieH
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hYN0Zii2yTb63jGxKY6gH1R/r9dL8kXaJmcZrfSa3AgywnteJWg=
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-----END RSA PRIVATE KEY-----
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-----BEGIN CERTIFICATE-----
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MIIDBjCCAe4CCQCX05m0b053QzANBgkqhkiG9w0BAQQFADBFMQswCQYDVQQGEwJB
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SEGI4JSxV56lYg==
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-----END CERTIFICATE-----
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Two aforementioned sections are clearly seen. Typically, those section
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are bigger then in the example shown. The text between the `BEGIN` and
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`END` is the text representation of binary data, a private key and a
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certificate. Therefore, in order to create a certificate file,
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* private key must be converted to PEM format
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* certificate must be converted to PEM format
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* those two should be concatenated into a single file
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If the certificate chain in used, a chain file also needs to be
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converted into PEM format and appended to the certificate file.
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## How SSL works
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SSL is a protocol that can encrypt communication between two parties. If third
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party observes all messages passed by, it would be very
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hard for the third party (though not impossible) to decrypt the communication.
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The idea is based on so-called public key encryption. Communicating parties
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have two keys: a public key and a private key. A public key is advertised
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to everybody, and it is contained in a certificate. A private key is kept
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secret. Security algorithm works in a way that anybody can encrypt
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a message using public key, and only private key can decrypt it.
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This is why web server needs both private key and certificate: private key
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is used to decrypt incoming messages, and certificate is used to tell the
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public key to the other party. When communication starts, parties exchange
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their public keys, and keep private keys to themselves. Man-in-the-middle
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who observes the communication is unable to decrypt the messages cause
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private keys are required for decryption.
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Encryption algorithms are built on top of hard mathematical problem, which
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makes it very expensive for man-in-the-middle to compute private keys.
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For example, RSA algorithm is based on a mathematical problem of factorization.
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It is easy to generate two very large prime numbers `P` and `Q` and make
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a product `P * Q`. But given a product, it is very hard to recover these
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two prime numbers - this is called factorization.
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