fix wrong git ignore

internal/pdf/core/ecb.go

@@ -0,0 +1,61 @@
+package core
+
+import "crypto/cipher"
+
+// ecb implements an Electronic Codebook encryption mode.
+// This mode is used to compute or validate document permissions for R=6.
+type ecb struct {
+	b         cipher.Block
+	blockSize int
+}
+
+func newECB(b cipher.Block) *ecb {
+	return &ecb{
+		b:         b,
+		blockSize: b.BlockSize(),
+	}
+}
+
+type ecbEncrypter ecb
+
+func newECBEncrypter(b cipher.Block) cipher.BlockMode {
+	return (*ecbEncrypter)(newECB(b))
+}
+
+func (x *ecbEncrypter) BlockSize() int { return x.blockSize }
+
+func (x *ecbEncrypter) CryptBlocks(dst, src []byte) {
+	if len(src)%x.blockSize != 0 {
+		panic("crypto/cipher: input not full blocks")
+	}
+	if len(dst) < len(src) {
+		panic("crypto/cipher: output smaller than input")
+	}
+	for len(src) > 0 {
+		x.b.Encrypt(dst, src[:x.blockSize])
+		src = src[x.blockSize:]
+		dst = dst[x.blockSize:]
+	}
+}
+
+type ecbDecrypter ecb
+
+func newECBDecrypter(b cipher.Block) cipher.BlockMode {
+	return (*ecbDecrypter)(newECB(b))
+}
+
+func (x *ecbDecrypter) BlockSize() int { return x.blockSize }
+
+func (x *ecbDecrypter) CryptBlocks(dst, src []byte) {
+	if len(src)%x.blockSize != 0 {
+		panic("crypto/cipher: input not full blocks")
+	}
+	if len(dst) < len(src) {
+		panic("crypto/cipher: output smaller than input")
+	}
+	for len(src) > 0 {
+		x.b.Decrypt(dst, src[:x.blockSize])
+		src = src[x.blockSize:]
+		dst = dst[x.blockSize:]
+	}
+}