diff --git a/Cargo.toml b/Cargo.toml
index 7fb578b..25803c2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,4 +5,5 @@ authors = ["Jake Probst <jake.probst@gmail.com>"]
 edition = "2018"
 
 [dependencies]
+rand = "0.6.5"
 psopacket = { path = "psopacket" }
\ No newline at end of file
diff --git a/src/crypto/bb.rs b/src/crypto/bb.rs
new file mode 100644
index 0000000..e69de29
diff --git a/src/crypto/mod.rs b/src/crypto/mod.rs
new file mode 100644
index 0000000..9267e49
--- /dev/null
+++ b/src/crypto/mod.rs
@@ -0,0 +1,14 @@
+mod pc;
+
+
+#[derive(Debug)]
+pub enum CipherError {
+    InvalidSize
+}
+
+
+
+trait PSOCipher {
+    fn encrypt(&mut self, data: &Vec<u8>) -> Result<Vec<u8>, CipherError>;
+    fn decrypt(&mut self, data: &Vec<u8>) -> Result<Vec<u8>, CipherError>;
+}
diff --git a/src/crypto/pc.rs b/src/crypto/pc.rs
new file mode 100644
index 0000000..09f1675
--- /dev/null
+++ b/src/crypto/pc.rs
@@ -0,0 +1,148 @@
+// implementation taken from kohle's newserv
+// https://github.com/fuzziqersoftware/newserv/
+
+use crate::crypto::{PSOCipher, CipherError};
+use std::num::Wrapping as W;
+
+const PC_STREAM_LENGTH: usize = 57;
+
+struct PSOPCCipher {
+  stream: [u32; PC_STREAM_LENGTH],
+  offset: u16,
+}
+
+impl PSOPCCipher {
+    pub fn new(seed: u32) -> PSOPCCipher {
+        let mut esi: W<u32>;
+        let mut ebx: W<u32>;
+        let mut edi: W<u32>;
+        let mut eax: W<u32>;
+        let mut edx: W<u32>;
+        let mut var1: W<u32>;
+
+        let mut stream: [u32; PC_STREAM_LENGTH] = [0; PC_STREAM_LENGTH];
+        
+        esi = W(1);
+        ebx = W(seed);
+        edi = W(0x15);
+        stream[56] = ebx.0;
+        stream[55] = ebx.0;
+        while edi <= W(0x46E) {
+            eax = edi;
+            var1 = eax / W(55);
+            edx = eax - (var1 * W(55));
+            ebx = ebx - esi;
+            edi = edi + W(0x15);
+            stream[edx.0 as usize] = esi.0;
+            esi = ebx;
+            ebx = W(stream[edx.0 as usize]);
+        }
+
+        let mut cipher = PSOPCCipher {
+            stream: stream,
+            offset: 1,
+        };
+        
+        for _ in 0..5 {
+            cipher.update_stream();
+        }
+
+        cipher
+    }
+   
+    fn update_stream(&mut self) {
+        let mut esi: W<u32>;
+        let mut edi: W<u32>;
+        let mut eax: W<u32>;
+        let mut ebp: W<u32>;
+        let mut edx: W<u32>;
+
+        edi = W(1);
+        edx = W(0x18);
+        eax = edi;
+        while edx > W(0) {
+            esi = W(self.stream[eax.0 as usize + 0x1F]);
+            ebp = W(self.stream[eax.0 as usize]);
+            ebp = ebp - esi;
+            self.stream[eax.0 as usize] = ebp.0;
+            eax += W(1);
+            edx -= W(1);
+        }
+        edi = W(0x19);
+        edx = W(0x1F);
+        eax = edi;
+        while edx > W(0) {
+            esi = W(self.stream[eax.0 as usize - 0x18]);
+            ebp = W(self.stream[eax.0 as usize]);
+            ebp = ebp - esi;
+            self.stream[eax.0 as usize] = ebp.0;
+            eax += W(1);
+            edx -= W(1);
+        }
+    }
+
+    fn next(&mut self) -> u32 {
+        if self.offset as usize == PC_STREAM_LENGTH {
+            self.update_stream();
+            self.offset = 1;
+        }
+
+        let result = self.stream[self.offset as usize];
+        self.offset += 1;
+        result
+    }
+}
+
+impl PSOCipher for PSOPCCipher {
+    fn encrypt(&mut self, data: &Vec<u8>) -> Result<Vec<u8>, CipherError> {
+        let mut result = Vec::new();
+        if data.len() % 4 != 0 {
+            return Err(CipherError::InvalidSize)
+        }
+
+        for c in data.chunks(4) {
+            let mut data = u32::from_le_bytes([c[0], c[1], c[2], c[3]]);
+            data ^= self.next();
+            result.extend_from_slice(&u32::to_le_bytes(data));
+        }
+        Ok(result)
+    }
+    
+    fn decrypt(&mut self, data: &Vec<u8>) -> Result<Vec<u8>, CipherError> {
+        self.encrypt(data)
+    }
+}
+
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_crypto() {
+        use rand::{Rng, RngCore};
+        use super::{PSOCipher, PSOPCCipher};
+
+        let mut rng = rand::thread_rng();
+
+        let seed: u32 = rng.gen();
+        let mut cipher_in = PSOPCCipher::new(seed);
+        let mut cipher_out = PSOPCCipher::new(seed);
+
+        for _ in 0..10 {
+            let mut random_junk = vec![0u8; 40];
+            rng.fill_bytes(&mut random_junk);
+        
+            let enc_data = cipher_in.encrypt(&random_junk).unwrap();
+            let orig_data = cipher_out.encrypt(&enc_data).unwrap();
+            
+            assert!(random_junk == orig_data);
+        }
+    }
+}
+
+
+
+
+
+
+
+
diff --git a/src/lib.rs b/src/lib.rs
index 3a99b69..f6a4483 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,4 @@
+mod crypto;
 mod patch;
 
 #[derive(Debug, PartialEq)]