Base64 in HTTP Basic Authentication: How It Works & Security Facts
Understand how HTTP Authorization: Basic headers encode credentials in Base64 and why HTTPS is mandatory to prevent credential sniffing.
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HTTP Basic Authentication is one of the oldest and simplest authentication schemes defined in RFC 7617. When a client requests a protected resource, the server challenges with a `401 Unauthorized` status and a `WWW-Authenticate: Basic realm="Access"` header.
How Credentials Are Formatted
The client responds by concatenating the username and password with a single colon: `username:password` This string is then encoded in Base64. For example, if username is `aladdin` and password is `opensesame`, the combined string is `aladdin:opensesame`. Encoded in Base64, this becomes `YWxhZGRpbjpvcGVuc2VzYW1l`.
The client then includes this in subsequent requests: `Authorization: Basic YWxhZGRpbjpvcGVuc2VzYW1l`
Crucial Security Warning: Base64 Is Not Encryption
Many novice developers mistakenly believe that because the password looks scrambled, it is protected. Any network eavesdropper inspecting plain HTTP packets can decode `YWxhZGRpbjpvcGVuc2VzYW1l` in less than one millisecond.
Therefore, HTTP Basic Authentication must always be served over TLS/HTTPS to encrypt the connection between client and server.
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