diff --git a/problems/p19/Cargo.toml b/problems/p19/Cargo.toml
new file mode 100644
index 0000000..7802d2d
--- /dev/null
+++ b/problems/p19/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "p19"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+base64 = { workspace = true }
diff --git a/problems/p19/src/main.rs b/problems/p19/src/main.rs
new file mode 100644
index 0000000..a1b31db
--- /dev/null
+++ b/problems/p19/src/main.rs
@@ -0,0 +1,123 @@
+// 使用瞪眼法判断
+// 结合gpt很快可以猜出来。
+use base64::{Engine as _, engine::general_purpose::STANDARD};
+use std::io::{Write, stdin, stdout};
+
+fn guess(idx: usize, seq: &str) {
+    let ciphers = [
+        "SSBoYXZlIG1ldCB0aGVtIGF0IGNsb3NlIG9mIGRheQ==",
+        "Q29taW5nIHdpdGggdml2aWQgZmFjZXM=",
+        "RnJvbSBjb3VudGVyIG9yIGRlc2sgYW1vbmcgZ3JleQ==",
+        "RWlnaHRlZW50aC1jZW50dXJ5IGhvdXNlcy4=",
+        "SSBoYXZlIHBhc3NlZCB3aXRoIGEgbm9kIG9mIHRoZSBoZWFk",
+        "T3IgcG9saXRlIG1lYW5pbmdsZXNzIHdvcmRzLA==",
+        "T3IgaGF2ZSBsaW5nZXJlZCBhd2hpbGUgYW5kIHNhaWQ=",
+        "UG9saXRlIG1lYW5pbmdsZXNzIHdvcmRzLA==",
+        "QW5kIHRob3VnaHQgYmVmb3JlIEkgaGFkIGRvbmU=",
+        "T2YgYSBtb2NraW5nIHRhbGUgb3IgYSBnaWJl",
+        "VG8gcGxlYXNlIGEgY29tcGFuaW9u",
+        "QXJvdW5kIHRoZSBmaXJlIGF0IHRoZSBjbHViLA==",
+        "QmVpbmcgY2VydGFpbiB0aGF0IHRoZXkgYW5kIEk=",
+        "QnV0IGxpdmVkIHdoZXJlIG1vdGxleSBpcyB3b3JuOg==",
+        "QWxsIGNoYW5nZWQsIGNoYW5nZWQgdXR0ZXJseTo=",
+        "QSB0ZXJyaWJsZSBiZWF1dHkgaXMgYm9ybi4=",
+        "VGhhdCB3b21hbidzIGRheXMgd2VyZSBzcGVudA==",
+        "SW4gaWdub3JhbnQgZ29vZCB3aWxsLA==",
+        "SGVyIG5pZ2h0cyBpbiBhcmd1bWVudA==",
+        "VW50aWwgaGVyIHZvaWNlIGdyZXcgc2hyaWxsLg==",
+        "V2hhdCB2b2ljZSBtb3JlIHN3ZWV0IHRoYW4gaGVycw==",
+        "V2hlbiB5b3VuZyBhbmQgYmVhdXRpZnVsLA==",
+        "U2hlIHJvZGUgdG8gaGFycmllcnM/",
+        "VGhpcyBtYW4gaGFkIGtlcHQgYSBzY2hvb2w=",
+        "QW5kIHJvZGUgb3VyIHdpbmdlZCBob3JzZS4=",
+        "VGhpcyBvdGhlciBoaXMgaGVscGVyIGFuZCBmcmllbmQ=",
+        "V2FzIGNvbWluZyBpbnRvIGhpcyBmb3JjZTs=",
+        "SGUgbWlnaHQgaGF2ZSB3b24gZmFtZSBpbiB0aGUgZW5kLA==",
+        "U28gc2Vuc2l0aXZlIGhpcyBuYXR1cmUgc2VlbWVkLA==",
+        "U28gZGFyaW5nIGFuZCBzd2VldCBoaXMgdGhvdWdodC4=",
+        "VGhpcyBvdGhlciBtYW4gSSBoYWQgZHJlYW1lZA==",
+        "QSBkcnVua2VuLCB2YWluLWdsb3Jpb3VzIGxvdXQu",
+        "SGUgaGFkIGRvbmUgbW9zdCBiaXR0ZXIgd3Jvbmc=",
+        "VG8gc29tZSB3aG8gYXJlIG5lYXIgbXkgaGVhcnQs",
+        "WWV0IEkgbnVtYmVyIGhpbSBpbiB0aGUgc29uZzs=",
+        "SGUsIHRvbywgaGFzIHJlc2lnbmVkIGhpcyBwYXJ0",
+        "SW4gdGhlIGNhc3VhbCBjb21lZHk7",
+        "SGUsIHRvbywgaGFzIGJlZW4gY2hhbmdlZCBpbiBoaXMgdHVybiw=",
+        "VHJhbnNmb3JtZWQgdXR0ZXJseTo=",
+        "QSB0ZXJyaWJsZSBiZWF1dHkgaXMgYm9ybi4=",
+    ]
+    .map(|x| STANDARD.decode(x).unwrap());
+    let seq = seq.as_bytes();
+    let key_stream: Vec<u8> = ciphers[idx].iter().zip(seq).map(|(a, b)| a ^ b).collect();
+    let plaintexts: Vec<Vec<u8>> = ciphers
+        .iter()
+        .map(|cipher| {
+            cipher
+                .iter()
+                .zip(key_stream.iter())
+                .map(|(&a, &b)| a ^ b)
+                .collect::<Vec<u8>>()
+        })
+        .collect();
+    for (k, v) in plaintexts.iter().enumerate() {
+        let v_str = String::from_utf8_lossy(v);
+        println!("{k}: {v_str}");
+    }
+}
+
+fn main() {
+    loop {
+        print!("> ");
+        stdout().flush().unwrap();
+        let mut input = String::new();
+        stdin().read_line(&mut input).expect("Failed to read input");
+        let input = input.trim_end_matches(['\n', '\r']);
+        let Some((idx, seq)) = input.split_once(" ") else {
+            println!("Please enter two parts separated by space");
+            continue;
+        };
+
+        guess(idx.parse().unwrap(), seq);
+    }
+
+    // 0: I have met them at close of day
+    // 1: Coming with vivid faces
+    // 2: From counter or desk among grey
+    // 3: Eighteenth-century houses.
+    // 4: I have passed with a nod of the head
+    // 5: Or polite meaningless words,
+    // 6: Or have lingered awhile and said
+    // 7: Polite meaningless words,
+    // 8: And thought before I had done
+    // 9: Of a mocking tale or a gibe
+    // 10: To please a companion
+    // 11: Around the fire at the club,
+    // 12: Being certain that they and I
+    // 13: But lived where motley is worn:
+    // 14: All changed, changed utterly:
+    // 15: A terrible beauty is born.
+    // 16: That woman's days were spent
+    // 17: In ignorant good will,
+    // 18: Her nights in argument
+    // 19: Until her voice grew shrill.
+    // 20: What voice more sweet than hers
+    // 21: When young and beautiful,
+    // 22: She rode to harriers?
+    // 23: This man had kept a school
+    // 24: And rode our winged horse.
+    // 25: This other his helper and friend
+    // 26: Was coming into his force;
+    // 27: He might have won fame in the end,
+    // 28: So sensitive his nature seemed,
+    // 29: So daring and sweet his thought.
+    // 30: This other man I had dreamed
+    // 31: A drunken, vain-glorious lout.
+    // 32: He had done most bitter wrong
+    // 33: To some who are near my heart,
+    // 34: Yet I number him in the song;
+    // 35: He, too, has resigned his part
+    // 36: In the casual comedy;
+    // 37: He, too, has been changed in his turn
+    // 38: Transformed utterly:
+    // 39: A terrible beauty is born.
+}