If you have a secure encryption algorithm, then whether or not you tell Eve the algorithm isn’t important. Yes, it makes the code-breaking harder for her, but that difficulty is a drop in the bucket, negligible compared to the difficulty of guessing the key.
Proper crypto must be secure whether or not the algorithm is known to attackers. Go ahead and keep the algorithm secret if you really want to, but you needn’t bother.
So it adds no significant difficulty when the plaintext is in a foreign language with few translators you have access to? It was pointless for the US military to use Navajo code-talkers? The shortage of Arabic translators imposes no notable cost on the CIA’s eavesdroppers?
Those things are difficult, sure, and I never said otherwise. But I’m not sure you appreciate just how staggeringly hard it is to break modern crypto. Navajo code-talkers are using a human language, with patterns that can be figured out by a properly determined adversary. There are quite a lot of people who can translate Arabic. Those are nowhere near the difficulty of, say, eavesdropping on a message encrypted with AES-128 when you don’t know the key. Or finding a collision with a given SHA-256 hash. Those things are hard.
If you have a secure encryption algorithm, then whether or not you tell Eve the algorithm isn’t important. Yes, it makes the code-breaking harder for her, but that difficulty is a drop in the bucket, negligible compared to the difficulty of guessing the key.
Proper crypto must be secure whether or not the algorithm is known to attackers. Go ahead and keep the algorithm secret if you really want to, but you needn’t bother.
So it adds no significant difficulty when the plaintext is in a foreign language with few translators you have access to? It was pointless for the US military to use Navajo code-talkers? The shortage of Arabic translators imposes no notable cost on the CIA’s eavesdroppers?
Those things are difficult, sure, and I never said otherwise. But I’m not sure you appreciate just how staggeringly hard it is to break modern crypto. Navajo code-talkers are using a human language, with patterns that can be figured out by a properly determined adversary. There are quite a lot of people who can translate Arabic. Those are nowhere near the difficulty of, say, eavesdropping on a message encrypted with AES-128 when you don’t know the key. Or finding a collision with a given SHA-256 hash. Those things are hard.