diff --git a/src/keygen/dell.spec.ts b/src/keygen/dell.spec.ts
index 4a172cb..687ad6f 100644
--- a/src/keygen/dell.spec.ts
+++ b/src/keygen/dell.spec.ts
@@ -52,6 +52,16 @@ describe("Test calculateSuffix", () => {
         expect(suffix).toEqual([117, 66, 48, 111, 83, 107, 85, 111]);
     });
 
+    it("Check tag suffix for: 1234567-1F5A", () => {
+        let suffix = checkSuffix("1234567", DellTag.Tag1F5A, SuffixType.ServiceTag);
+        expect(suffix).toEqual([101, 103, 102, 117, 115, 100, 97, 117]);
+    });
+
+    it("Check tag suffix for: ABCDEFG-1F5A", () => {
+        let suffix = checkSuffix("ABCDEFG", DellTag.Tag1F5A, SuffixType.ServiceTag);
+        expect(suffix).toEqual([0x74, 0x6e, 0x76, 0x75, 0x69, 0x6f, 0x74, 0x68]);
+    });
+
     // HDD
     it("Check hdd suffix for: 12345678901-595B", () => {
         let suffix = checkSuffix("12345678901", DellTag.Tag595B, SuffixType.HDD);
@@ -144,8 +154,23 @@ describe("Test keygenDell", () => {
     });
     it("Dell password for: 8M5RQ32-1F66", () => {
         expect(keygenDell("8M5RQ32", DellTag.Tag1F66, SuffixType.ServiceTag))
-        .toEqual("3rlrbaSj46Iw221g");
+        .toEqual("3rlrbaSj46Iw221g"); });
+
+    it("Dell password for: 1234567-1F5A", () => {
+        expect(keygenDell("1234567", DellTag.Tag1F5A, SuffixType.ServiceTag))
+        .toEqual("2ls2b8GiP9H032kx");
     });
+
+    it("Dell password for: OPENSRC-1F5A", () => {
+        expect(keygenDell("OPENSRC", DellTag.Tag1F5A, SuffixType.ServiceTag))
+        .toEqual("ZC3j2t56eIe4Thgi");
+    });
+
+    it("Dell password for: ABCDEFG-1F5A", () => {
+        expect(keygenDell("ABCDEFG", DellTag.Tag1F5A, SuffixType.ServiceTag))
+        .toEqual("x2zL5n7jj2Gl2TIh");
+    });
+
     // HDD
     it("Dell HDD password for: 1234567890A-595B", () => {
         expect(keygenDell("1234567890A", DellTag.Tag595B, SuffixType.HDD))
@@ -175,6 +200,7 @@ describe("Test keygenDell", () => {
         expect(keygenDell("1234567890A", DellTag.Tag6FF1, SuffixType.HDD))
         .toEqual("5enLLpM3Immfb8CK");
     });
+    // TODO: add HDD 1F5A
 });
 
 describe("Test Dell BIOS", () => {
diff --git a/src/keygen/dell/encode.ts b/src/keygen/dell/encode.ts
index 4e4a989..e0e3220 100644
--- a/src/keygen/dell/encode.ts
+++ b/src/keygen/dell/encode.ts
@@ -59,6 +59,7 @@ interface Encoder {
     encode(data: number[]): number[];
 }
 
+// Maybe optimize ? return (((param2 >>> (0x20 - param7))) | (param2 << param7)) + num1;
 function rol(x: number, bitsrot: number): number {
     // n >>> 0 used to convert signed number to unsigned
     // (unsigned(x) >> (32 - bitsrot)) | (unsigned(x) << bitsrot);
@@ -168,7 +169,7 @@ class Tag595BEncoder {
     }
 
     public result(): number[] {
-        return this.encData.map((v) => v | 0);
+        return this.encData.map((v) => (v | 0) >>> 0);
     }
 
     public static encode(encBlock: number[]): number[] {
@@ -355,6 +356,60 @@ class Tag6FF1Encoder extends Tag595BEncoder {
     }
 }
 
+class Tag1F5AEncoder extends Tag595BEncoder {
+    protected md5table = md5magic2;
+    protected f1 = encF1N;
+    protected f2 = encF2N;
+    protected f3 = encF3;
+    protected f4 = encF4N;
+    protected f5 = encF5N;
+
+    protected incrementData() {
+        this.encData[0] += this.B;
+        this.encData[1] += this.C;
+        this.encData[2] += this.A;
+        this.encData[3] += this.D;
+
+        this.encData.forEach((val, index) => {
+            this.encData[index] = val | 0;
+        });
+    }
+
+    protected calculate(func: EncFunction, key1: number, key2: number): number {
+        let temp = func(this.C, this.A, this.D);
+        return this.B + this.f1(temp, this.md5table[key2] + this.encBlock[key1]) | 0;
+    }
+
+    public makeEncode(): void {
+        let t: number = 0;
+        for (let i = 0; i < 5; i++) {
+            for (let j = 0; j < 64; j++) {
+                let k = 12 + (j & 3) - (j & 12);
+                switch (j >> 4) {
+                    case 0:
+                        t = this.calculate(this.f2, j & 15, j);
+                        break;
+                    case 1:
+                        t = this.calculate(this.f3, (j * 5 + 1) & 15, j);
+                        break;
+                    case 2:
+                        t = this.calculate(this.f4, (j * 3 + 5) & 15, k + 0x20);
+                        break;
+                    case 3:
+                        t = this.calculate(this.f5, (j * 7) & 15, k + 0x30);
+                        break;
+                }
+                this.B = this.D;
+                this.D = this.A;
+                this.A = this.C;
+                this.C = rol(t, rotationTable[j >> 4][j & 3]) + this.C | 0;
+            }
+
+            this.incrementData();
+        }
+    }
+}
+
 const encoders: {readonly [P in DellTag]: Encoder} = {
     "595B": Tag595BEncoder,
     "2A7B": Tag595BEncoder, // same as 595B
@@ -362,7 +417,8 @@ const encoders: {readonly [P in DellTag]: Encoder} = {
     "1D3B": Tag1D3BEncoder,
     "D35B": TagD35BEncoder,
     "1F66": Tag1F66Encoder,
-    "6FF1": Tag6FF1Encoder
+    "6FF1": Tag6FF1Encoder,
+    "1F5A": Tag1F5AEncoder
 };
 
 export function blockEncode(encBlock: number[], tag: DellTag): number[] {
diff --git a/src/keygen/dell/index.ts b/src/keygen/dell/index.ts
index 13d5c31..b3dafc9 100644
--- a/src/keygen/dell/index.ts
+++ b/src/keygen/dell/index.ts
@@ -13,8 +13,11 @@ const encscans: number[] = [
     0x24, 0x23, 0x31, 0x20, 0x1E, 0x08, 0x2D, 0x21, 0x04, 0x0B, 0x12, 0x2E
 ];
 
+const asciiPrintable = "012345679abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ0";
+
 const extraCharacters: {readonly [P in DellTag]?: string} = {
-    "2A7B": "012345679abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ0",
+    "2A7B": asciiPrintable,
+    "1F5A": asciiPrintable,
     "1D3B": "0BfIUG1kuPvc8A9Nl5DLZYSno7Ka6HMgqsJWm65yCQR94b21OTp7VFX2z0jihE33d4xtrew0",
     "1F66": "0ewr3d4xtUG1ku0BfIp7VFb21OTSno7KDLZYqsJWa6HMgCQR94m65y9Nl5Pvc8AjihE3X2z0",
     "6FF1": "08rptBxfbGVMz38IiSoeb360MKcLf4QtBCbWVzmH5wmZUcRR5DZG2xNCEv1nFtzsZB2bw1X0"
diff --git a/src/keygen/dell/types.ts b/src/keygen/dell/types.ts
index fb5400b..8813712 100644
--- a/src/keygen/dell/types.ts
+++ b/src/keygen/dell/types.ts
@@ -6,7 +6,8 @@ export enum DellTag {
     TagA95B = "A95B",
     Tag1D3B = "1D3B",
     Tag6FF1 = "6FF1",
-    Tag1F66 = "1F66"
+    Tag1F66 = "1F66",
+    Tag1F5A = "1F5A"
 }
 
 export const enum SuffixType {