{"id":5516,"date":"2019-05-02T13:30:12","date_gmt":"2019-05-02T17:30:12","guid":{"rendered":"https:\/\/www.thesslstore.com\/blog\/?p=5516"},"modified":"2025-10-16T15:49:55","modified_gmt":"2025-10-16T19:49:55","slug":"what-is-256-bit-encryption","status":"publish","type":"post","link":"https:\/\/www.thesslstore.com\/blog\/what-is-256-bit-encryption\/","title":{"rendered":"How strong is 256-bit Encryption?"},"content":{"rendered":"\n

\u201cIt says 256-bit encryption strength\u2026 is that good?\u201d<\/h2>\n\n\n\n

Most people see the term 256-bit encryption bandied about all the time and \u2013 if we\u2019re being honest \u2013 have absolutely no idea what it means or how strong it is. Once you go beyond the surface-level, \u201cit scrambles data and makes it unreadable,\u201d encryption is an incredibly complicated subject. It\u2019s not a light read. Most of us don\u2019t keep a book about modular exponentiation on the end table beside our beds.<\/p>\n\n\n\n

That’s why it\u2019s understandable that there would be some confusion when it comes to encryption strengths, what they mean, what\u2019s \u201cgood,\u201d etc. There\u2019s no shortage of questions about encryption \u2013 specifically 256-bit encryption. <\/p>\n\n\n\n

Chief among them: How strong is 256-bit encryption?<\/p>\n\n\n\n

So, today we\u2019re going to talk about just that. We\u2019ll cover\nwhat a bit of security even is, we\u2019ll get into the most common form of 256-bit\nencryption and we\u2019ll talk about just what it would take to crack encryption at\nthat strength. <\/p>\n\n\n\n

Let\u2019s hash it out.<\/span><\/p>\n\n\n\n

A quick refresher on encryption, in general<\/h2>\n\n\n\n

When you encrypt something, you\u2019re taking the unencrypted\ndata, called plaintext, and performing an algorithmic function on it to create\na piece of encrypted ciphertext. The algorithm you\u2019re using is called the key. With\nthe exception of public keys in asymmetric encryption, the value of the\nencryption key needs to be kept a secret. The private key associated with that\npiece of ciphertext is the only practical means of decrypting it. <\/p>\n\n\n\n

Now, that all sounds incredibly abstract, so let\u2019s use an example. And we\u2019ll leave Bob and Alice out of it, as they\u2019re busy explaining encryption in literally every other example on the internet<\/a>. <\/p>\n\n\n\n

Let\u2019s go with Jack and Diane, and let\u2019s say that Jack wants to send Diane a message that says, \u201cOh yeah, life goes on.\u201d <\/p>\n\n\n\n

Jack\u2019s going to take his message and he\u2019s going to use an algorithm\nor cipher \u2013 the encryption key \u2013 to scramble the message into ciphertext. Now\nhe\u2019ll pass it along to Diane, along with the key, which can be used to decrypt\nthe message so that it\u2019s readable again. <\/p>\n\n\n\n

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As long as nobody else gets their hands on the key, the\nciphertext is worthless because it can\u2019t be read. <\/p>\n\n\n<\/span><\/span>\n\n\n\n

How does modern encryption work?<\/h2>\n\n\n\n

Jack and Diane just demonstrated encryption at its most\nbasic form. And while the math used in primitive ciphers was fairly simple \u2013\nowing to the fact it had to be performed by a human \u2013 the advent of computers\nhas increased the complexity of the math that undergirds modern cryptosystems.\nBut the concepts are still largely the same. <\/p>\n\n\n\n

A key, or specific algorithm, is used to encrypt the data,\nand only another party with knowledge of the associated private key can decrypt\nit. <\/p>\n\n\n\n

In this example, rather than a written message that bleakly opines that life continues even after the joy is lost, Jack and Diane are ‘doing the best they can’ on computers (still ‘holdin\u2019 on to 16’ \u2013 sorry, these are John Mellencamp jokes that probably make no sense outside of the US). Now the encryption that\u2019s about to take place is digital.<\/p>\n\n\n\n

\"256-bit<\/figure>\n\n\n\n

Jack\u2019s computer will use its key, which is really an extremely complicated algorithm that has been derived from data shared by Jack and Diane’s devices<\/a>, to encrypt the plaintext. Diane uses her matching symmetric key to decrypt and read the data.<\/p>\n\n\n\n

But what\u2019s actually getting encrypted? How do you encrypt \u201cdata?\u201d<\/h2>\n\n\n\n

In the original example there were actual letters on a physical piece of paper that were turned into something else. But how does a computer encrypt data? <\/p>\n\n\n\n

That goes back to the way that computers actually deal in data. Computers store information in binary form. 1\u2019s and 0\u2019s. Any data input into a computer is encoded so that it\u2019s readable by the machine. It\u2019s that encoded data, in its raw form, that gets encrypted. This is actually part of what goes into the different file types used by SSL\/TLS certificates<\/a>, it\u2019s partially contingent on what type of encoding scheme you\u2019re trying to encrypt.<\/p>\n\n\n\n

Related<\/strong>: Secure Your Website with a Comodo SSL Certificate<\/a>. <\/em><\/p>\n\n\n\n

So Jack\u2019s computer encrypts the encoded data and transmits\nit to Diane\u2019s computer, which uses the associated private key to decrypt and read\nthe data. <\/p>\n\n\n

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Again, as long as the private key stays, you know\u2026 private,\nthe encryption remains secure.<\/p>\n\n\n\n

Modern encryption has solved the biggest historical obstacle to encryption<\/a>: key exchange. Historically, the private key had to be physically passed off. Key security was literally a matter of physically storing the key in a safe place. Key compromise not only rendered the encryption moot, it could get you killed<\/a>. <\/p>\n\n\n\n

In the 1970s a trio of cryptographers, Ralph Merkle,\nWhitfield Diffie and Martin Hellman, began working on a way to securely share\nan encryption key on an unsecure network with an attacker watching. They succeeded\non a theoretical level, but were unable to come up with an asymmetric\nencryption function that was practical. They also had no mechanism for authenticating\n(but that\u2019s a totally different conversation). Merkle came up with the initial\nconcept, but his name is not associated with the key exchange protocol they\ninvented \u2013 despite the protests of its other two creators. <\/p>\n\n\n\n

About a year later Ron Rivest, Adi Shamir and Leonard Adleman created an eponymous key exchange method based on Diffie-Hellman key exchange (RSA<\/a>), one that also included encryption\/decryption and authentication functions. This is relevant because it was the birth of a whole new iteration of encryption: asymmetric encryption. <\/p>\n\n\n\n

They also gave us the aforementioned Bob and Alice, which to me at least, makes it kind of a wash. <\/p>\n\n\n\n

Anyway, understanding the difference between symmetric and asymmetric encryption is key to the rest of this discussion. <\/p>\n\n\n<\/span><\/span>\n\n\n\n

Asymmetric Encryption vs. Symmetric Encryption<\/h2>\n\n\n\n

Symmetric encryption<\/a> is sometimes called private key encryption<\/a>, because both parties must share a symmetric key that can be used to both encrypt and decrypt data. <\/p>\n\n\n

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\"Symmetric<\/figure>\n<\/div>\n\n\n

Asymmetric encryption on the other hand is sometimes called public key encryption. A better way to think of asymmetric encryption might be to think of it like one-way encryption. <\/p>\n\n\n\n

As opposed to both parties sharing a private key, there is a key pair. One party possess a public key that can encrypt, the other possesses a private key that can decrypt. <\/p>\n\n\n

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Asymmetric encryption is used primarily as a mechanism for exchanging symmetric private keys. There\u2019s a reason for this, asymmetric encryption is historically a more expensive function owing to the size of its keys. So public key cryptography is used more as an external wall to help protect the parties as they facilitate a connection, while symmetric encryption is used within the actual connection itself.<\/p>\n\n\n\n

2048-bit keys vs. 256-bit keys<\/h2>\n\n\n\n

In SSL\/TLS, asymmetric encryption serves one, extremely important function. It lets the client encrypt the data that will be used by both parties to derive the symmetric session keys they\u2019ll use to communicate<\/a>. You could never use asymmetric encryption to functionally communicate. While the public key can be used to verify a digital signature<\/a>, it can\u2019t outright decrypt anything that the private key encrypts, hence we call asymmetric encryption \u201cone way.\u201d<\/p>\n\n\n

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But the bigger issue is the key size makes the actual encryption and decryption functions expensive in terms of the CPU resources they gobble up. This is why many larger organizations and enterprises, when deploying SSL\/TLS at scale, offload the handshakes<\/a>: to free up resources on their application servers. <\/p>\n\n\n\n

Instead, we use symmetric encryption for the actual\ncommunication that occurs during an encrypted connection. Symmetric keys are\nsmaller and less expensive to compute with. <\/p>\n\n\n\n

So, when you see someone reference a 2048-bit private key, they\u2019re most likely referring to an RSA private key. That\u2019s an asymmetric key. It needs to be sufficiently resistant to attacks because it carries out such a critical function. Also, because key exchange is the best attack vector for compromising a connection. It\u2019s much easier to steal the data used to create the symmetric session key and calculate it yourself than to have to crack the key by brute force after it\u2019s already in use. <\/p>\n\n\n\n

That begs the question: \u201cHow strong IS 256-bit encryption?\u201d If it\u2019s less robust than a 2048-bit key, is it still sufficient? And we\u2019re going to answer that, but first we need to cover a little more ground for the sake of providing the right context.<\/p>\n\n\n\n

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