diff --git a/data/shared/src/main/scala/sigma/data/UnsignedBigIntegerOps.scala b/data/shared/src/main/scala/sigma/data/UnsignedBigIntegerOps.scala
index e66740b1e..e0170b14d 100644
--- a/data/shared/src/main/scala/sigma/data/UnsignedBigIntegerOps.scala
+++ b/data/shared/src/main/scala/sigma/data/UnsignedBigIntegerOps.scala
@@ -1,6 +1,7 @@
 package sigma.data
 
 import sigma._
+import sigma.crypto.BigIntegers
 import sigma.data.UnsignedBigIntOrderingOps.UnsignedBigIntOrdering
 import sigma.eval.Extensions.IntExt
 
@@ -98,9 +99,13 @@ object UnsignedBigIntNumericOps {
     override def toBigEndianBytes(x: UnsignedBigInt): Coll[Byte] = x.toBytes
 
     /**
-      * @return a numeric value which is inverse of `x` (every bit, including sign, is flipped)
+      * @return a numeric value which is inverse of `x` (every bit is flipped)
       */
-    override def bitwiseInverse(x: UnsignedBigInt): UnsignedBigInt = ???
+    override def bitwiseInverse(x: UnsignedBigInt): UnsignedBigInt = {
+      val bytes = BigIntegers.asUnsignedByteArray(x.asInstanceOf[CUnsignedBigInt].wrappedValue)
+      val res: Array[Byte] = bytes.map(b => (b ^ Byte.MinValue).toByte)
+      CUnsignedBigInt(BigIntegers.fromUnsignedByteArray(res))
+    }
 
     /**
       * @return a numeric value which is `this | that`
diff --git a/sc/shared/src/test/scala/sigmastate/utxo/BasicOpsSpecification.scala b/sc/shared/src/test/scala/sigmastate/utxo/BasicOpsSpecification.scala
index 9a7afd40a..6c95071a0 100644
--- a/sc/shared/src/test/scala/sigmastate/utxo/BasicOpsSpecification.scala
+++ b/sc/shared/src/test/scala/sigmastate/utxo/BasicOpsSpecification.scala
@@ -829,6 +829,23 @@ class BasicOpsSpecification extends CompilerTestingCommons
     }
   }
 
+  property("UnsignedBigInt.bitwiseInverse") {
+    def bitwiseInverseTest(): Assertion = test("UnsignedBigInt.bitwiseInverse", env, ext,
+      s"""{
+         | val b = unsignedBigInt("${CryptoConstants.groupOrder}")
+         | val bi = b.bitwiseInverse
+         | bi.bitwiseInverse == b
+         |}""".stripMargin,
+      null
+    )
+
+    if (VersionContext.current.isV6SoftForkActivated) {
+      bitwiseInverseTest()
+    } else {
+      an[sigma.validation.ValidationException] shouldBe thrownBy(bitwiseInverseTest())
+    }
+  }
+
 
   property("Byte.bitwiseInverse") {
     def bitwiseInverseTest(): Assertion = test("Byte.bitwiseInverse", env, ext,