Add keypair & update pubkey

Keypair & FullKeypair match structs in damus ios

Signed-off-by: kernelkind <kernelkind@gmail.com>
Signed-off-by: William Casarin <jb55@jb55.com>

enostr/src/pubkey.rs

@@ -1,14 +1,15 @@
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 
 use crate::Error;
-use hex;
 use log::debug;
-//use nostr::key::XOnlyPublicKey;
+use nostr::bech32::Hrp;
 use std::fmt;
 
 #[derive(Debug, Eq, PartialEq, Clone, Hash)]
 pub struct Pubkey([u8; 32]);
 
+static HRP_NPUB: Hrp = Hrp::parse_unchecked("npub");
+
 impl Pubkey {
     pub fn new(data: &[u8; 32]) -> Self {
         Self(*data)
@@ -25,6 +26,41 @@ impl Pubkey {
     pub fn from_hex(hex_str: &str) -> Result<Self, Error> {
         Ok(Pubkey(hex::decode(hex_str)?.as_slice().try_into()?))
     }
+
+    pub fn try_from_hex_str_with_verify(hex_str: &str) -> Result<Self, Error> {
+        let vec: Vec<u8> = hex::decode(hex_str)?;
+        if vec.len() != 32 {
+            Err(Error::HexDecodeFailed)
+        } else {
+            let _ = match nostr::secp256k1::XOnlyPublicKey::from_slice(&vec) {
+                Ok(r) => Ok(r),
+                Err(_) => Err(Error::InvalidPublicKey),
+            }?;
+
+            Ok(Pubkey(vec.try_into().unwrap()))
+        }
+    }
+
+    pub fn try_from_bech32_string(s: &str, verify: bool) -> Result<Self, Error> {
+        let data = match nostr::bech32::decode(s) {
+            Ok(res) => Ok(res),
+            Err(_) => Err(Error::InvalidBech32),
+        }?;
+
+        if data.0 != HRP_NPUB {
+            Err(Error::InvalidBech32)
+        } else if data.1.len() != 32 {
+            Err(Error::InvalidByteSize)
+        } else {
+            if verify {
+                let _ = match nostr::secp256k1::XOnlyPublicKey::from_slice(&data.1) {
+                    Ok(r) => Ok(r),
+                    Err(_) => Err(Error::InvalidPublicKey),
+                }?;
+            }
+            Ok(Pubkey(data.1.try_into().unwrap()))
+        }
+    }
 }
 
 impl fmt::Display for Pubkey {