The public key is meant to be available to sign data for that person. you do this so they can un-encrypt the data but they know it was signed. and only they can un-encrypt that data. On Mon, Feb 16, 2015 at 8:28 PM, Michael Havens wrote: > That is where I was befuddled. I didn't realize that the public/private > keys belonged to the same person. So when we get a message with a key on it > that is the public key and everyone has access to it and that will > encrypt/decrypt a message if we know how to use it.. And then originator of > the key has the private key to do the opposite as was done to the message > before it was sent. > > :-)~MIKE~(-: > > On Mon, Feb 16, 2015 at 8:18 PM, Stephen Partington > wrote: > >> Stolen but relevant. >> >> The Public and Private key pair comprise of two uniquely related >> cryptographic keys (basically long random numbers). Below is an example of >> a Public Key: >> >> 3048 0241 00C9 18FA CF8D EB2D EFD5 FD37 89B9 E069 EA97 FC20 5E35 F577 >> EE31 C4FB C6E4 4811 7D86 BC8F BAFA 362F 922B F01B 2F40 C744 2654 C0DD 2881 >> D673 CA2B 4003 C266 E2CD CB02 0301 0001 >> >> The Public Key is what its name suggests - Public. It is made available >> to everyone via a publicly accessible repository or directory. On the other >> hand, the Private Key must remain confidential to its respective owner. >> >> Because the key pair is mathematically related, whatever is encrypted >> with a Public Key may only be decrypted by its corresponding Private Key >> and vice versa. >> >> For example, if Bob wants to send sensitive data to Alice, and wants to >> be sure that only Alice may be able to read it, he will encrypt the data >> with Alice's Public Key. Only Alice has access to her corresponding Private >> Key and as a result is the only person with the capability of decrypting >> the encrypted data back into its original form. >> >> As only Alice has access to her Private Key, it is possible that only >> Alice can decrypt the encrypted data. Even if someone else gains access to >> the encrypted data, it will remain confidential as they should not have >> access to Alice's Private Key. >> >> From >> https://www.comodo.com/resources/small-business/digital-certificates2.php >> On Feb 16, 2015 7:57 PM, "Michael Havens" wrote: >> >>> no.... no..... Joseph says it is like two locks.When you unlock one you >>> lock the other? hmmmm.... >>> >>> :-)~MIKE~(-: >>> >>> On Mon, Feb 16, 2015 at 7:49 PM, Michael Havens >>> wrote: >>> >>>> and then the public key everyone can see and the private one only you >>>> can see? >>>> >>>> :-)~MIKE~(-: >>>> >>>> On Mon, Feb 16, 2015 at 7:45 PM, Michael Havens >>>> wrote: >>>> >>>>> is a real simplified version that it is like two locks locked together >>>>> and each key opens one of the locks? >>>>> >>>>> :-)~MIKE~(-: >>>>> >>>>> On Mon, Feb 9, 2015 at 7:05 PM, Joseph Sinclair < >>>>> plug-discussion@stcaz.net> wrote: >>>>> >>>>>> Lots of confusion here. Let me try to clarify (a small amount). >>>>>> >>>>>> Background: >>>>>> "Public Key" cryptography is also called "Asymmetric Cryptography". >>>>>> The reason is that there are two different keys, and they only work >>>>>> together in an "asymmetric" fashion (whatever one key does, the other key >>>>>> undoes). >>>>>> The keys are "related" mathematically, but it is (currently) not >>>>>> possible to figure out one key from the other (so having a public key does >>>>>> not help you determine the private key). >>>>>> >>>>>> 1) There are two keys. >>>>>> a) There are also two *actions*, encryption (hiding content from >>>>>> unauthorized viewers) and verification (proving a message is authentic and >>>>>> from a known entity). >>>>>> 2) *Either* key can be used to encrypt, but the *other* key is needed >>>>>> to decrypt. >>>>>> a) that means public(encrypt) ==> private(decrypt) *or* >>>>>> private(encrypt) ==> public(decrypt). >>>>>> b) a single key cannot both encrypt and decrypt the same message >>>>>> (That's why it's called "asymmetric encryption", the keys are *not* >>>>>> interchangeable). >>>>>> 3) The "Public" key is meant to be published far and wide. It is >>>>>> used to encrypt a message intended for the key "owner", and it is also used >>>>>> (by decrypting a hash) to "verify" that a message was sent by the real >>>>>> owner (signature). >>>>>> 4) The "Private" key is meant to be kept strictly secret. It can >>>>>> decrypt any message encrypted by the public key. It can also encrypt a >>>>>> message that only the "Public" key can decrypt (see signature below). >>>>>> >>>>>> Encryption is the function most people understand (it's also very >>>>>> rarely used**). You encrypt a message using the "Public" key as the >>>>>> encryption key. >>>>>> Once encrypted the data is essentially static to anyone who does not >>>>>> possess the "Private" key. >>>>>> There are a ton of details involved, so it's rarely explained further >>>>>> than that without reading an entire textbook (or 3). >>>>>> >>>>>> There is a *related* function called "verification" or "Digital >>>>>> Signature". This is used to prove (without ever exposing a secret) that a >>>>>> particular entity possesses the secret "Private" key. >>>>>> This is how you know your HTTPS connection is connected to the >>>>>> correct endpoint rather than some imposter (it's also how ssh passwordless >>>>>> login works). >>>>>> This involves (very simplified) using the "Private" key to encrypt >>>>>> the hash of a message (to sign the message) or a "nonce" value (to verify >>>>>> endpoint identity, e.g. SSL). >>>>>> Once the value (hash or nonce) is encrypted by the "Private" key, >>>>>> only the matching "Public" key will decrypt it. >>>>>> So if someone sent you a message and it's encrypted hash, then you >>>>>> decrypt the hash with the "Public" key, and if it decrypts correctly you >>>>>> know it is valid. >>>>>> Of course, you would also hash the message (there are standard >>>>>> algorithms for generating these "hash" values) and see if your results >>>>>> match what you decrypted (if they don't, then the message isn't what the >>>>>> sender meant to send). >>>>>> >>>>>> There are several ways of implementing assymetric cryptography, the >>>>>> most commonly used is with the RSA family of algorithms. >>>>>> The "elliptic curve" (or "EC") family of algorithms have grown in >>>>>> popularity in recent years, but are still only occasionally used. >>>>>> The two are mostly different in the mathematics behind how and why >>>>>> they work. >>>>>> The basic concepts (two keys, two operations, what one key does the >>>>>> other undoes) are the same. >>>>>> >>>>>> Hopefully that helps a bit. >>>>>> >>>>>> Public Key Cryptography (and Asymmetric Cryptography in general) is a >>>>>> huge and complex topic, so I second Todd's suggestion that if you want to >>>>>> really understand this, you will want to read a few good textbooks on the >>>>>> subject. >>>>>> >>>>>> ==Joseph++ >>>>>> >>>>>> ** Some will say that SSL uses public key encryption. This is true, >>>>>> but misleading, because the public key encryption is only used during the >>>>>> "handshake" where the SSL connection is setup to encrypt the exchange of >>>>>> symmetric keys. This "key exchange" is what Diffie and Helman invented >>>>>> that makes modern PKI possible. >>>>>> The encryption that does all the heavy lifting of keeping the SSL >>>>>> tunnel secure is always a "block" (symmetric) algorithm, most commonly AES >>>>>> (for modern systems where security is properly implemented) or 3DES >>>>>> (slightly older but still pretty secure) or RC4 (completely insecure and >>>>>> used by extremely badly managed sites running ancient and horribly flawed >>>>>> web server software, unfortunately there are still far too many very large >>>>>> businesses that do this). >>>>>> >>>>>> >>>>>> On 02/09/2015 06:01 PM, Michael Havens wrote: >>>>>> > helps some but you state: >>>>>> > >>>>>> > you want others to be able to check that you actually >>>>>> > sent the message (by using your public key) >>>>>> > >>>>>> > Where do they get your public key? >>>>>> > How does your public key and private key decrypt when it seems the >>>>>> public >>>>>> > key changes. >>>>>> > >>>>>> > :-)~MIKE~(-: >>>>>> > >>>>>> > On Mon, Feb 9, 2015 at 5:48 PM, someone wrote: >>>>>> > >>>>>> >> So if I'm right calling it a 'key' is a misnomer. I am a very >>>>>> literal >>>>>> >> person. if they call it a key it unlocks things, not creates them. >>>>>> >> That is where my confusion is from. Am I correct? >>>>>> >> >>>>>> >> Not quite correct... >>>>>> >> >>>>>> >> Both the public and private keys ARE keys... they're just used a >>>>>> >> little differently. >>>>>> >> >>>>>> >> You keep your private key secure, and use it to digitally sign a >>>>>> >> message when you want others to be able to check that you actually >>>>>> >> sent the message (by using your public key). Others can send an >>>>>> >> encrypted message that only you can decode, by encrypting the >>>>>> message >>>>>> >> using your public key. When you get the message, you can use your >>>>>> >> private key to undo the encryption that was done using your public >>>>>> >> key. >>>>>> >> >>>>>> >> So, in a way, the public and private keys can be thought of as two >>>>>> >> pieces of a single, combined key. The software that does the >>>>>> signing >>>>>> >> or encryption (using the keys), such as gnupg, pgp, etc., is more >>>>>> like >>>>>> >> the lock that the keys fit. >>>>>> >> >>>>>> >> I hope that helps. >>>>>> >> -- >>>>>> >> Kevin O'Connor >>>>>> >> >>>>>> > >>>>>> > >>>>>> > >>>>>> > --------------------------------------------------- >>>>>> > PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org >>>>>> > To subscribe, unsubscribe, or to change your mail settings: >>>>>> > http://lists.phxlinux.org/mailman/listinfo/plug-discuss >>>>>> > >>>>>> >>>>>> >>>>>> --------------------------------------------------- >>>>>> PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org >>>>>> To subscribe, unsubscribe, or to change your mail settings: >>>>>> http://lists.phxlinux.org/mailman/listinfo/plug-discuss >>>>>> >>>>> >>>>> >>>> >>> >>> --------------------------------------------------- >>> PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org >>> To subscribe, unsubscribe, or to change your mail settings: >>> http://lists.phxlinux.org/mailman/listinfo/plug-discuss >>> >> >> --------------------------------------------------- >> PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org >> To subscribe, unsubscribe, or to change your mail settings: >> http://lists.phxlinux.org/mailman/listinfo/plug-discuss >> > > > --------------------------------------------------- > PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org > To subscribe, unsubscribe, or to change your mail settings: > http://lists.phxlinux.org/mailman/listinfo/plug-discuss > -- A mouse trap, placed on top of your alarm clock, will prevent you from rolling over and going back to sleep after you hit the snooze button. Stephen