keypairs sign --exp 1h key.jwk.json '{ "sub": "me@example.com" }' > token.jwt 2> sig.jws
```
+A JWT (JSON Web Token) has 3 sections (protected header, payload, and signature)
+separated by dots (`.`):
+
+```txt
+eyJhbGciOiJFUzI1NiIsImtpZCI6ImpkeHhZY1NCZUJfeUdoZWlCVW14NjF0eHExZGFjR1hIX191bEJuWlZHMEUiLCJ0eXAiOiJKV1QifQ.eyJleHAiOjE1NDU5MzkxNzksInN1YiI6Im1lQGV4YW1wbGUuY29tIn0.izlx0ylMtxqof7PABjpFAlP-1tNslEFoosHPCVTD-D1aIY7rq1jZikQerdA0lFEEsiD9D_DdBW3Eaq9s63jcBA
+```
+
+A JWS (JSON Web Signature), is just a parsed JWT:
+
+```json
+{
+ "claims": {
+ "exp": 1545939179,
+ "sub": "me@example.com"
+ },
+ "header": {
+ "alg": "ES256",
+ "kid": "jdxxYcSBeB_yGheiBUmx61txq1dacGXH__ulBnZVG0E",
+ "typ": "JWT"
+ },
+ "payload": "eyJleHAiOjE1NDU5MzkxNzksInN1YiI6Im1lQGV4YW1wbGUuY29tIn0",
+ "protected": "eyJhbGciOiJFUzI1NiIsImtpZCI6ImpkeHhZY1NCZUJfeUdoZWlCVW14NjF0eHExZGFjR1hIX191bEJuWlZHMEUiLCJ0eXAiOiJKV1QifQ",
+ "signature": "izlx0ylMtxqof7PABjpFAlP-1tNslEFoosHPCVTD-D1aIY7rq1jZikQerdA0lFEEsiD9D_DdBW3Eaq9s63jcBA"
+}
+```
+
+Note that self-signed JWTs and JWSes will use `jwk` as the full public key
+rather than the `kid` thumbprint.
+
### How to verify a signature
```bash
-# keypairs sign --exp 1h <pub key> <signed file or data>
-keypairs sign --exp 1h pub.jwk.json token.jwt
+# keypairs verify <pub key> <signed file or data>
+keypairs verify pub.jwk.json token.jwt
+```
+
+You can use files or strings.
+
+```bash
+keypairs verify \
+ '{ "crv": "P-256", "d": "hYmoRZJp8b98wl0Daw49R1NjHfDhGNXP34-QyaCuZIk", "kty": "EC", "x": "5K5ALgtWw37KsZOrBdwCyGOGKCFd27u-t61dmUiieJY", "y": "wr3BNL-CeqkGtiRVqo3yizKxUA0bwS1MNZeqytdwICA" }' \
+ eyJhbGciOiJFUzI1NiIsImtpZCI6ImpkeHhZY1NCZUJfeUdoZWlCVW14NjF0eHExZGFjR1hIX191bEJuWlZHMEUiLCJ0eXAiOiJKV1QifQ.eyJleHAiOjE1NDU5MzkxNzksInN1YiI6Im1lQGV4YW1wbGUuY29tIn0.izlx0ylMtxqof7PABjpFAlP-1tNslEFoosHPCVTD-D1aIY7rq1jZikQerdA0lFEEsiD9D_DdBW3Eaq9s63jcBA
```
+
+### What do RSA and ECDSA JWKs look like?
+
+`keypairs` will generate either ECDSA or RSA at random and only support
+NIST-approved, industry-standard key types and options.
+
+#### ECDSA Private
+
+`[ "crv", "d", "kty", "x", "y" ]`
+
+```json
+{
+ "crv": "P-256",
+ "d": "hYmoRZJp8b98wl0Daw49R1NjHfDhGNXP34-QyaCuZIk",
+ "kty": "EC",
+ "x": "5K5ALgtWw37KsZOrBdwCyGOGKCFd27u-t61dmUiieJY",
+ "y": "wr3BNL-CeqkGtiRVqo3yizKxUA0bwS1MNZeqytdwICA"
+}
+```
+
+#### ECDSA Public
+
+`[ "crv", "kid", "kty", "use", "x", "y" ]`
+
+```json
+{
+ "crv": "P-256",
+ "kid": "jdxxYcSBeB_yGheiBUmx61txq1dacGXH__ulBnZVG0E",
+ "kty": "EC",
+ "use": "sig",
+ "x": "5K5ALgtWw37KsZOrBdwCyGOGKCFd27u-t61dmUiieJY",
+ "y": "wr3BNL-CeqkGtiRVqo3yizKxUA0bwS1MNZeqytdwICA"
+}
+```
+
+Note that `kid` is the thumbprint, and `use` is omitted when generating
+thumbprint.
+
+#### RSA Private
+
+`[ "d", "dp", "dq", "e", "kty", "n", "p", "q", "qi" ]`
+
+```json
+{
+ "d": "cNTQBfVY_4zmQDZWUXILKVRldEwF6ujxQ08PGOSOczHQaoCdTVJtXlio7IZLbLLpG_doxgNr_VFtk64SaAgTs5fBA5SK8x-Xy44L8pl5c7Vlc7Am-fI5hTkWle79ZP5KygvXP34pgDMwQUqJfUEkJ8UwgW9ffO_OFJCBUnPwVG0PCfmGZi1usTtr0Kix31zOWPAdogVEMUoqRrrn_Maw8CUVUfr-k-xCo8pFTCJk3K5O7ZldZd9GotcdNUyL5_BsvD3iLIok6DFmZjt6Kfbf1Pu0yGw3deU9by8XQlG4zNW0ABdRYRGxbOn4ZTZYqiMqK2I47gv5RJkFeFfJKgdzAQ",
+ "dp": "WskCm6kAxywgOWBMHx8LtBUVqknK47pXHYa0tThyukclUS6NoGpm-rNAHQDyf_IF-237TzTmU5Qp3Oumybg8QvrmG7h3CbnxYplJdOvFFm3rtyUZ_rBAP-cXZYrqU3E8IArI3cKW1sXHS2S_9z8D0aI7jZ9IAJc29xSvSz9kFAk",
+ "dq": "W-R3Z-WVeEnHArVNvKlmjaHowemvQ67enefAkvrI3zQT537BxT1NS7cY27ehTl5x0dnywd-U3qObyYAGX34AMXyTLpKFwqkbd8zysZghAZPWtTUk09qYEwiC1cS3xl6D0Yyxg5KCFrLNQ33JY8CdDq0kY_JThUyAf6REcXSYokE",
+ "e": "AQAB",
+ "kty": "RSA",
+ "n": "vm0SbK4I_4LwXrLU6PR69Y331HJNXNCdPvlD4EZMUCqjQj-M6F7lopWeXBQy93H06s1LnLfdaE1-gRQv0ptzDNaupObi1SOeZiSmqaXJ3sQl0l01i4FXYvUboRrQWWsqkDwh1Azth7sf4m5nNfhqK_D4jfmtYoOAL-DsFXJ2018amcKBuiesOPXl4rw2BoHQoTXJq7YfWKpDWnm6s6zXLubTmHG9jv7NUKqoqCen6NJMSTP40uKA2LjEnkbxw2JwKm0KlBPuLvkrYECwpUGzqYboXfrulif9TS9p5nWXM1dLKN1rN91zqGZw_idXs6ebJW3x47J9Ta9dvD5wqsRh-Q",
+ "p": "yrDgavzG6bvvX4kpWbuvlWZZVXHkCS9zRlNbzEa-zqMmvfrckNc7b3VBAm8Id5-hgrHLnSOc7qG8t5xDPAKiNMXf2_ya-eLmCIAPwI5GzMNxFmKyvxUCN2z9lMASrwvxtV9dX4bIExZToN7NQqxAZwgn6BgMsmR_l7olo8nsUfU",
+ "q": "8IJn1cQaellOe0zi5zWF4QGzfARtu-6vKMvNkGRlB6gws3j6pIzd54IXa6O2H7tMjsK0jDXi3Wh4M1IdcGxJHT9aPt9UIdlgW1zbLhN-DfQku-i1_bQ4vMZ6_kchpZsDRbCIQ290ZfWSTaYp5EtBGM359W-jAH2v-IYtCuN6GXU",
+ "qi": "XFoxKvgujg1fwRsUiaKb7ptTxboGPWjcjivP67Hk-T28JfevJoyQQk2YmLqQLZZFr5uZ-POIIP2GQd-k2yXDyPsZXXe0-QTY4t0g2HXHInE4meROfnqfNjsijBrNqEQz_mqs9714tQXNdjpOExSUceh2DpepaS1z73gsqwTqeWI"
+}
+```
+
+#### RSA Public
+
+`[ "e", "kid", "kty", "n", "use" ]`
+
+```json
+{
+ "e": "AQAB",
+ "kid": "4GTGYg18yQLUndStAb65ZqPfDdWiBtYl4gzDZosSD38",
+ "kty": "RSA",
+ "n": "vm0SbK4I_4LwXrLU6PR69Y331HJNXNCdPvlD4EZMUCqjQj-M6F7lopWeXBQy93H06s1LnLfdaE1-gRQv0ptzDNaupObi1SOeZiSmqaXJ3sQl0l01i4FXYvUboRrQWWsqkDwh1Azth7sf4m5nNfhqK_D4jfmtYoOAL-DsFXJ2018amcKBuiesOPXl4rw2BoHQoTXJq7YfWKpDWnm6s6zXLubTmHG9jv7NUKqoqCen6NJMSTP40uKA2LjEnkbxw2JwKm0KlBPuLvkrYECwpUGzqYboXfrulif9TS9p5nWXM1dLKN1rN91zqGZw_idXs6ebJW3x47J9Ta9dvD5wqsRh-Q",
+ "use": "sig"
+}
+```
+
+Note that `kid` is the thumbprint, and `use` is omitted when generating
+thumbprint.