多个字符串 Base64 解码为相同的字节数组
Multiple strings Base64-decoded to same byte-array
我有一个字节数组（我们称之为加密消息），我对其进行 Base64 编码以获取输出字符串（我们称之为令牌）。稍后，我将对该令牌进行 Base64 解码，以恢复原始的加密消息。
出于测试目的，我尝试在令牌中注入一个随机位翻转，以验证 encryption/authentication 在翻转一个随机位时确实失败了。 99% 的情况下，情况确实如此。 1-3% 的时间不会发生这种情况。我已将其调试回以下行为：2 个不同的标记，在 Base64 解码时都产生相同的字节数组。
，但就我而言，这 2 个标记实际上在中间有所不同。
这种情况发生的频率也很令人费解。鉴于字节缓冲区中有 ~1kB，即使 1-2 字节仅用于填充并且没有意义，随机位翻转命中填充字节的几率应该是 ~0.1%。我发现这种行为发生的概率 >1%。
这种行为合理吗？还是我的代码中存在更深层次的问题？
问题总结: 2个不同的字符串，中间相差1位翻转，是否有可能在Base64解码时产生相同的字节数组？对于具有 1 个随机位翻转的 1kB 缓冲区，这种情况在 1% 的时间内发生是否合理？
完整详情
我正在使用 Java 的 BASE64 encoder/decoder 类 进行以下所有操作。
String token = new BASE64Encoder().encode(encryptedMessage);
...
byte[] tokenBytes = token.getBytes();
int randomIndex = new Random().nextInt(tokenBytes.length);
int randomBit = 1 << new Random().nextInt(8);
tokenBytes[randomIndex] ^= randomBit;
token = new String(tokenBytes)
....
byte[] finalEncryptedMessage = new BASE64Decoder().decodeBuffer(token);
checkFinalEncryptedMessage!=initialEncryptedMessage
原始加密消息（字节数组）：
[52, -11, 14, -3, 10, 92, 65, -46, -54, -25, 117, -126, 15, 2, -72, 123, -119, 111, -115, 114, -11, 48, -6, 47, 72, -47, 117, 76, -17, 82, 98, 23, 124, -99, 92, -45, 92, 48, -116, 20, -90, 52, 94, -25, -116, 7, 112, -51, 20, -2, -66, 126, 11, 117, 81, 33, 27, -116, -46, -115, -64, -7, -83, 78, -113, 85, -106, -70, 46, 35, 42, -51, 118, -40, 40, 99, -29, -78, -117, -34, -65, -49, -18, -98, -84, 79, -115, -42, 93, 55, -115, -71, 6, 8, 106, -11, -5, 12, 11, -61, -9, -31, -114, 112, -119, 31, 37, 125, -9, 82, -53, 90, -43, 77, -53, -114, 118, 9, -68, 93, -48, 116, -116, 54, -82, 6, -52, 64, -66, 54, -34, 51, -3, -83, 49, -79, 81, -88, -122, -113, 6, -102, -11, 60, -128, 12, -105, -66, 4, -80, -2, -106, -73, 117, 55, -14, 96, 96, 107, -41, 16, 10, -83, -60, -88, -25, 49, -30, 19, 48, -85, -65, -70, -90, 0, -43, 100, 7, -106, 77, 70, -8, -87, 16, 108, 49, 102, -91, 41, -31, -45, 101, 61, -11, 108, -23, -117, 16, 52, -30, -46, -106, 78, 114, 64, -31, -82, 40, -109, 97, 61, -54, 50, -70, -106, -82, -21, -14, 78, -93, 101, -68, 107, 22, 18, 115, 3, 125, 44, -106, 126, -109, 8, -90, -81, 118, -34, 98, -111, -73, -67, -39, -51, -85, -104, 41, -37, 31, -29, 26, -114, -88, -116, -89, 27, -36, 74, -99, 101, -13, 76, 126, 1, -32, 59, 80, -102, -93, -92, 30, -49, -87, -28, -70, 88, 16, 117, 37, -49, 56, -6, 106, -74, -60, -71, -72, -91, -81, -9, -122, 53, -126, 28, -16, -126, -14, -24, -89, 19, -17, 20, 110, -25, 73, -74, 67, -65, 78, 103, 107, 116, -63, 84, -113, -114, -114, 24, 66, -6, -74, -71, 126, -112, 68, -37, 117, -88, 92, -13, 39, 18, -44, 92, 97, -84, -111, -118, -13, -73, -60, 69, -43, 74, 38, -89, 82, 74, 33, -41, 73, 87, 12, -114, 0, -48, 80, 1, -79, -53, -19, -4, 60, -8, 108, -85, -54, 104, 36, 77, -6, 30, 78, -104, 120, 33, 85, -87, -86, -57, -102, 97, -111, 43, 29, -63, 103, 101, 57, 64, 124, 53, -43, 118, 103, 107, 77, -97, 81, 90, 90, -102, 28, -57, 26, 18, -26, -21, 92, 36, -83, 22, 57, -33, 112, 1, -46, -23, -51, 121, 68, 45, -89, -25, -42, 103, 30, -113, -120, 36, 0, 19, 60, -28, 15, -63, -8, 97, -117, -69, -86, -55, -114, -89, -78, -5, -60, 86, 41, 117, -85, -38, -106, 2, -126, -107, 89, -93, -72, 20, 11, 48, 117, -57, -52, -9, 29, 54, -28, -13, 95, -100, 62, 107, -126, -22, -110, 40, -14, -110, 22, -10, -107, -87, -8, 45, -117, -3, -59, 22, 68, 92, 97, 48, -47, 90, 72, -13, 116, 50, 86, -44, -106, 95, -30, -89, 6, -69, 77, -64, 98, -110, 40, -59, -60, 58, 58, -11, -83, 81, -59, 65, 56, 105, 94, -2, 110, 73, 125, 46, 42, -52, 68, -28, 25, 97, -111, -98, -51, -50, 43, -31, -92, -88, 99, 26, -81, -62, 104, -117, -87, 70, -75, 26, -68, 18, -35, -4, 92, 79, -63, -24, 42, 34, 96, 63, -78, 58, -52, -71, 79, -121, 81, 65, 69, -24, -23, 55, -49, 10, 11, 33, -2, -8, 105, -95, -15, 6, 66, -121, 13, -124, -21, -103, -30, -56, -72, -44, 61, -67, -24, 96, -81, 20, -38, -21, -93, -35, 25, -105, -116, -15, -3, 71, 77, 0, -108, 85, 63, -114, 82, 31, -28, -61, -116, 74, 9, -1, -88, 67, 92, 14, 1, -90, -55, 105, -31, 5, -91, 123, 105, 2, -44, 71, 31, 8, 6, -68, 5, -35, 66, 112, 120, -38, 48, 85, 67, 89, -103, -43, 29, 120, 16, -4, 53, 72, -36, -56, 9, 42, -32, -98, -24, 66, 70, 54, -112, 73, -59, -124, 4, -51, 84, -120, 1, -18, -70, 66, -85, 27, 127, -85, -19, 117, -91, -63, 94, -46, 97, -35, -105, -84, -81, -118, -81, 107, 63, 65, -109, -36, -49, 111, -8, 77, 57, -91, -49, 2, 93, 103, 71, 48, 38, 28, 102, 9, -13, 25, 121, 95, -75, 69, -74, -18, -112, -122, -59, 17, -26, 81, 123, 54, 56, -127, -92, 32, 12, 86, 103, -84, 39, -18, 78, 100, 62, -78, -56, 84, -65, 80, -78, 102, -9, -48, 73, -98, 118, 74, 116, 39, -103, -127, 33, 48, -6, -48, 10, -69, -11, 118, -51, 1, -56, -59, -48, 103, -105, -109, -29, -100, 77, 66, 4, -85, -93, 46, -64, 61, -57, -111, -29, 89, -25, 126, -89, 65, -32, 33, -65, -70, 36, -19, -18, -79, 88, -79, 20, -91, -71, 13, -114, -44, 68, -14, -48, 106, -46, 105, 126, -6, -72, 113, -117, -46, 9, 27, -55, 113, 19, -69, -15, 36, -117, -90, 35, 122, 64, -108, -56]
原始令牌（经过上述Base64编码后）：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=
损坏的令牌（请参阅第 7 行的位翻转。/替换为？）
NPUO/QpcQdLK53WCDwK4e4lvjXL1MPovSNF1TO9SYhd8nVzTXDCMFKY0XueMB3DNFP6+fgt1USEb
jNKNwPmtTo9VlrouIyrNdtgoY+Oyi96/z+6erE+N1l03jbkGCGr1+wwLw/fhjnCJHyV991LLWtVN
y452Cbxd0HSMNq4GzEC+Nt4z/a0xsVGoho8GmvU8gAyXvgSw/pa3dTfyYGBr1xAKrcSo5zHiEzCr
v7qmANVkB5ZNRvipEGwxZqUp4dNlPfVs6YsQNOLSlk5yQOGuKJNhPcoyupau6/JOo2W8axYScwN9
LJZ+kwimr3beYpG3vdnNq5gp2x/jGo6ojKcb3EqdZfNMfgHgO1Cao6Qez6nkulgQdSXPOPpqtsS5
uKWv94Y1ghzwgvLopxPvFG7nSbZDv05na3TBVI+OjhhC+ra5fpBE23WoXPMnEtRcYayRivO3xEXV
SianUkoh10lXDI4A0FABscvt?Dz4bKvKaCRN+h5OmHghVamqx5phkSsdwWdlOUB8NdV2Z2tNn1Fa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=
经过Base64解码后的最终加密信息：
[52, -11, 14, -3, 10, 92, 65, -46, -54, -25, 117, -126, 15, 2, -72, 123, -119, 111, -115, 114, -11, 48, -6, 47, 72, -47, 117, 76, -17, 82, 98, 23, 124, -99, 92, -45, 92, 48, -116, 20, -90, 52, 94, -25, -116, 7, 112, -51, 20, -2, -66, 126, 11, 117, 81, 33, 27, -116, -46, -115, -64, -7, -83, 78, -113, 85, -106, -70, 46, 35, 42, -51, 118, -40, 40, 99, -29, -78, -117, -34, -65, -49, -18, -98, -84, 79, -115, -42, 93, 55, -115, -71, 6, 8, 106, -11, -5, 12, 11, -61, -9, -31, -114, 112, -119, 31, 37, 125, -9, 82, -53, 90, -43, 77, -53, -114, 118, 9, -68, 93, -48, 116, -116, 54, -82, 6, -52, 64, -66, 54, -34, 51, -3, -83, 49, -79, 81, -88, -122, -113, 6, -102, -11, 60, -128, 12, -105, -66, 4, -80, -2, -106, -73, 117, 55, -14, 96, 96, 107, -41, 16, 10, -83, -60, -88, -25, 49, -30, 19, 48, -85, -65, -70, -90, 0, -43, 100, 7, -106, 77, 70, -8, -87, 16, 108, 49, 102, -91, 41, -31, -45, 101, 61, -11, 108, -23, -117, 16, 52, -30, -46, -106, 78, 114, 64, -31, -82, 40, -109, 97, 61, -54, 50, -70, -106, -82, -21, -14, 78, -93, 101, -68, 107, 22, 18, 115, 3, 125, 44, -106, 126, -109, 8, -90, -81, 118, -34, 98, -111, -73, -67, -39, -51, -85, -104, 41, -37, 31, -29, 26, -114, -88, -116, -89, 27, -36, 74, -99, 101, -13, 76, 126, 1, -32, 59, 80, -102, -93, -92, 30, -49, -87, -28, -70, 88, 16, 117, 37, -49, 56, -6, 106, -74, -60, -71, -72, -91, -81, -9, -122, 53, -126, 28, -16, -126, -14, -24, -89, 19, -17, 20, 110, -25, 73, -74, 67, -65, 78, 103, 107, 116, -63, 84, -113, -114, -114, 24, 66, -6, -74, -71, 126, -112, 68, -37, 117, -88, 92, -13, 39, 18, -44, 92, 97, -84, -111, -118, -13, -73, -60, 69, -43, 74, 38, -89, 82, 74, 33, -41, 73, 87, 12, -114, 0, -48, 80, 1, -79, -53, -19, -4, 60, -8, 108, -85, -54, 104, 36, 77, -6, 30, 78, -104, 120, 33, 85, -87, -86, -57, -102, 97, -111, 43, 29, -63, 103, 101, 57, 64, 124, 53, -43, 118, 103, 107, 77, -97, 81, 90, 90, -102, 28, -57, 26, 18, -26, -21, 92, 36, -83, 22, 57, -33, 112, 1, -46, -23, -51, 121, 68, 45, -89, -25, -42, 103, 30, -113, -120, 36, 0, 19, 60, -28, 15, -63, -8, 97, -117, -69, -86, -55, -114, -89, -78, -5, -60, 86, 41, 117, -85, -38, -106, 2, -126, -107, 89, -93, -72, 20, 11, 48, 117, -57, -52, -9, 29, 54, -28, -13, 95, -100, 62, 107, -126, -22, -110, 40, -14, -110, 22, -10, -107, -87, -8, 45, -117, -3, -59, 22, 68, 92, 97, 48, -47, 90, 72, -13, 116, 50, 86, -44, -106, 95, -30, -89, 6, -69, 77, -64, 98, -110, 40, -59, -60, 58, 58, -11, -83, 81, -59, 65, 56, 105, 94, -2, 110, 73, 125, 46, 42, -52, 68, -28, 25, 97, -111, -98, -51, -50, 43, -31, -92, -88, 99, 26, -81, -62, 104, -117, -87, 70, -75, 26, -68, 18, -35, -4, 92, 79, -63, -24, 42, 34, 96, 63, -78, 58, -52, -71, 79, -121, 81, 65, 69, -24, -23, 55, -49, 10, 11, 33, -2, -8, 105, -95, -15, 6, 66, -121, 13, -124, -21, -103, -30, -56, -72, -44, 61, -67, -24, 96, -81, 20, -38, -21, -93, -35, 25, -105, -116, -15, -3, 71, 77, 0, -108, 85, 63, -114, 82, 31, -28, -61, -116, 74, 9, -1, -88, 67, 92, 14, 1, -90, -55, 105, -31, 5, -91, 123, 105, 2, -44, 71, 31, 8, 6, -68, 5, -35, 66, 112, 120, -38, 48, 85, 67, 89, -103, -43, 29, 120, 16, -4, 53, 72, -36, -56, 9, 42, -32, -98, -24, 66, 70, 54, -112, 73, -59, -124, 4, -51, 84, -120, 1, -18, -70, 66, -85, 27, 127, -85, -19, 117, -91, -63, 94, -46, 97, -35, -105, -84, -81, -118, -81, 107, 63, 65, -109, -36, -49, 111, -8, 77, 57, -91, -49, 2, 93, 103, 71, 48, 38, 28, 102, 9, -13, 25, 121, 95, -75, 69, -74, -18, -112, -122, -59, 17, -26, 81, 123, 54, 56, -127, -92, 32, 12, 86, 103, -84, 39, -18, 78, 100, 62, -78, -56, 84, -65, 80, -78, 102, -9, -48, 73, -98, 118, 74, 116, 39, -103, -127, 33, 48, -6, -48, 10, -69, -11, 118, -51, 1, -56, -59, -48, 103, -105, -109, -29, -100, 77, 66, 4, -85, -93, 46, -64, 61, -57, -111, -29, 89, -25, 126, -89, 65, -32, 33, -65, -70, 36, -19, -18, -79, 88, -79, 20, -91, -71, 13, -114, -44, 68, -14, -48, 106, -46, 105, 126, -6, -72, 113, -117, -46, 9, 27, -55, 113, 19, -69, -15, 36, -117, -90, 35, 122, 64, -108, -56]
简答为 "no"。
任何字节流 B 都有一个 base64 编码 E。编码流 E 是解码为字节流 B 的唯一有效字节流。这就是 B64 的工作方式。
在您的示例中，您将字符串中的一个字符更改为标准 base64 中无效的字符。解码器如何处理这将是特定于实现的。
您已将该字符更改为无效的 base64 字符。因此结果将是特定于解码器的。
您的测试表明，某些 base64 解码器比其他解码器更能处理无效的 base64 字符。最好的解决方案是使用 Base64 解码器，其记录的错误行为符合您的预期。 Java 8 现在有两个，java.util.Base64 that debuted in Java 8, and some methods in javax.xml.bind.DatatypeConverter that have been around since at least Java 6. There are also other classes out there, such as the iHarder base64 class which has a nice page describing it and other base64 decoders, and the base64 decoder in Apache Commons Codec.
有一个
请注意，上面提供的某些库在解码无效的 Base64 字符时也不会抛出异常。这是我通过试验不同的 Base64 库发现的。最终，我通过显式检查我的位翻转是否产生了 Base64 字符解决了这个问题。如果没有，我取消位翻转并选择一个新的位进行翻转。
我有一个字节数组（我们称之为加密消息），我对其进行 Base64 编码以获取输出字符串（我们称之为令牌）。稍后，我将对该令牌进行 Base64 解码，以恢复原始的加密消息。
出于测试目的，我尝试在令牌中注入一个随机位翻转，以验证 encryption/authentication 在翻转一个随机位时确实失败了。 99% 的情况下，情况确实如此。 1-3% 的时间不会发生这种情况。我已将其调试回以下行为：2 个不同的标记，在 Base64 解码时都产生相同的字节数组。
这种情况发生的频率也很令人费解。鉴于字节缓冲区中有 ~1kB，即使 1-2 字节仅用于填充并且没有意义，随机位翻转命中填充字节的几率应该是 ~0.1%。我发现这种行为发生的概率 >1%。
这种行为合理吗？还是我的代码中存在更深层次的问题？
问题总结: 2个不同的字符串，中间相差1位翻转，是否有可能在Base64解码时产生相同的字节数组？对于具有 1 个随机位翻转的 1kB 缓冲区，这种情况在 1% 的时间内发生是否合理？
完整详情
我正在使用 Java 的 BASE64 encoder/decoder 类 进行以下所有操作。
String token = new BASE64Encoder().encode(encryptedMessage);
...
byte[] tokenBytes = token.getBytes();
int randomIndex = new Random().nextInt(tokenBytes.length);
int randomBit = 1 << new Random().nextInt(8);
tokenBytes[randomIndex] ^= randomBit;
token = new String(tokenBytes)
....
byte[] finalEncryptedMessage = new BASE64Decoder().decodeBuffer(token);
checkFinalEncryptedMessage!=initialEncryptedMessage
原始加密消息（字节数组）：
[52, -11, 14, -3, 10, 92, 65, -46, -54, -25, 117, -126, 15, 2, -72, 123, -119, 111, -115, 114, -11, 48, -6, 47, 72, -47, 117, 76, -17, 82, 98, 23, 124, -99, 92, -45, 92, 48, -116, 20, -90, 52, 94, -25, -116, 7, 112, -51, 20, -2, -66, 126, 11, 117, 81, 33, 27, -116, -46, -115, -64, -7, -83, 78, -113, 85, -106, -70, 46, 35, 42, -51, 118, -40, 40, 99, -29, -78, -117, -34, -65, -49, -18, -98, -84, 79, -115, -42, 93, 55, -115, -71, 6, 8, 106, -11, -5, 12, 11, -61, -9, -31, -114, 112, -119, 31, 37, 125, -9, 82, -53, 90, -43, 77, -53, -114, 118, 9, -68, 93, -48, 116, -116, 54, -82, 6, -52, 64, -66, 54, -34, 51, -3, -83, 49, -79, 81, -88, -122, -113, 6, -102, -11, 60, -128, 12, -105, -66, 4, -80, -2, -106, -73, 117, 55, -14, 96, 96, 107, -41, 16, 10, -83, -60, -88, -25, 49, -30, 19, 48, -85, -65, -70, -90, 0, -43, 100, 7, -106, 77, 70, -8, -87, 16, 108, 49, 102, -91, 41, -31, -45, 101, 61, -11, 108, -23, -117, 16, 52, -30, -46, -106, 78, 114, 64, -31, -82, 40, -109, 97, 61, -54, 50, -70, -106, -82, -21, -14, 78, -93, 101, -68, 107, 22, 18, 115, 3, 125, 44, -106, 126, -109, 8, -90, -81, 118, -34, 98, -111, -73, -67, -39, -51, -85, -104, 41, -37, 31, -29, 26, -114, -88, -116, -89, 27, -36, 74, -99, 101, -13, 76, 126, 1, -32, 59, 80, -102, -93, -92, 30, -49, -87, -28, -70, 88, 16, 117, 37, -49, 56, -6, 106, -74, -60, -71, -72, -91, -81, -9, -122, 53, -126, 28, -16, -126, -14, -24, -89, 19, -17, 20, 110, -25, 73, -74, 67, -65, 78, 103, 107, 116, -63, 84, -113, -114, -114, 24, 66, -6, -74, -71, 126, -112, 68, -37, 117, -88, 92, -13, 39, 18, -44, 92, 97, -84, -111, -118, -13, -73, -60, 69, -43, 74, 38, -89, 82, 74, 33, -41, 73, 87, 12, -114, 0, -48, 80, 1, -79, -53, -19, -4, 60, -8, 108, -85, -54, 104, 36, 77, -6, 30, 78, -104, 120, 33, 85, -87, -86, -57, -102, 97, -111, 43, 29, -63, 103, 101, 57, 64, 124, 53, -43, 118, 103, 107, 77, -97, 81, 90, 90, -102, 28, -57, 26, 18, -26, -21, 92, 36, -83, 22, 57, -33, 112, 1, -46, -23, -51, 121, 68, 45, -89, -25, -42, 103, 30, -113, -120, 36, 0, 19, 60, -28, 15, -63, -8, 97, -117, -69, -86, -55, -114, -89, -78, -5, -60, 86, 41, 117, -85, -38, -106, 2, -126, -107, 89, -93, -72, 20, 11, 48, 117, -57, -52, -9, 29, 54, -28, -13, 95, -100, 62, 107, -126, -22, -110, 40, -14, -110, 22, -10, -107, -87, -8, 45, -117, -3, -59, 22, 68, 92, 97, 48, -47, 90, 72, -13, 116, 50, 86, -44, -106, 95, -30, -89, 6, -69, 77, -64, 98, -110, 40, -59, -60, 58, 58, -11, -83, 81, -59, 65, 56, 105, 94, -2, 110, 73, 125, 46, 42, -52, 68, -28, 25, 97, -111, -98, -51, -50, 43, -31, -92, -88, 99, 26, -81, -62, 104, -117, -87, 70, -75, 26, -68, 18, -35, -4, 92, 79, -63, -24, 42, 34, 96, 63, -78, 58, -52, -71, 79, -121, 81, 65, 69, -24, -23, 55, -49, 10, 11, 33, -2, -8, 105, -95, -15, 6, 66, -121, 13, -124, -21, -103, -30, -56, -72, -44, 61, -67, -24, 96, -81, 20, -38, -21, -93, -35, 25, -105, -116, -15, -3, 71, 77, 0, -108, 85, 63, -114, 82, 31, -28, -61, -116, 74, 9, -1, -88, 67, 92, 14, 1, -90, -55, 105, -31, 5, -91, 123, 105, 2, -44, 71, 31, 8, 6, -68, 5, -35, 66, 112, 120, -38, 48, 85, 67, 89, -103, -43, 29, 120, 16, -4, 53, 72, -36, -56, 9, 42, -32, -98, -24, 66, 70, 54, -112, 73, -59, -124, 4, -51, 84, -120, 1, -18, -70, 66, -85, 27, 127, -85, -19, 117, -91, -63, 94, -46, 97, -35, -105, -84, -81, -118, -81, 107, 63, 65, -109, -36, -49, 111, -8, 77, 57, -91, -49, 2, 93, 103, 71, 48, 38, 28, 102, 9, -13, 25, 121, 95, -75, 69, -74, -18, -112, -122, -59, 17, -26, 81, 123, 54, 56, -127, -92, 32, 12, 86, 103, -84, 39, -18, 78, 100, 62, -78, -56, 84, -65, 80, -78, 102, -9, -48, 73, -98, 118, 74, 116, 39, -103, -127, 33, 48, -6, -48, 10, -69, -11, 118, -51, 1, -56, -59, -48, 103, -105, -109, -29, -100, 77, 66, 4, -85, -93, 46, -64, 61, -57, -111, -29, 89, -25, 126, -89, 65, -32, 33, -65, -70, 36, -19, -18, -79, 88, -79, 20, -91, -71, 13, -114, -44, 68, -14, -48, 106, -46, 105, 126, -6, -72, 113, -117, -46, 9, 27, -55, 113, 19, -69, -15, 36, -117, -90, 35, 122, 64, -108, -56]
原始令牌（经过上述Base64编码后）：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=
损坏的令牌（请参阅第 7 行的位翻转。/替换为？）
NPUO/QpcQdLK53WCDwK4e4lvjXL1MPovSNF1TO9SYhd8nVzTXDCMFKY0XueMB3DNFP6+fgt1USEb
jNKNwPmtTo9VlrouIyrNdtgoY+Oyi96/z+6erE+N1l03jbkGCGr1+wwLw/fhjnCJHyV991LLWtVN
y452Cbxd0HSMNq4GzEC+Nt4z/a0xsVGoho8GmvU8gAyXvgSw/pa3dTfyYGBr1xAKrcSo5zHiEzCr
v7qmANVkB5ZNRvipEGwxZqUp4dNlPfVs6YsQNOLSlk5yQOGuKJNhPcoyupau6/JOo2W8axYScwN9
LJZ+kwimr3beYpG3vdnNq5gp2x/jGo6ojKcb3EqdZfNMfgHgO1Cao6Qez6nkulgQdSXPOPpqtsS5
uKWv94Y1ghzwgvLopxPvFG7nSbZDv05na3TBVI+OjhhC+ra5fpBE23WoXPMnEtRcYayRivO3xEXV
SianUkoh10lXDI4A0FABscvt?Dz4bKvKaCRN+h5OmHghVamqx5phkSsdwWdlOUB8NdV2Z2tNn1Fa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=
经过Base64解码后的最终加密信息：
[52, -11, 14, -3, 10, 92, 65, -46, -54, -25, 117, -126, 15, 2, -72, 123, -119, 111, -115, 114, -11, 48, -6, 47, 72, -47, 117, 76, -17, 82, 98, 23, 124, -99, 92, -45, 92, 48, -116, 20, -90, 52, 94, -25, -116, 7, 112, -51, 20, -2, -66, 126, 11, 117, 81, 33, 27, -116, -46, -115, -64, -7, -83, 78, -113, 85, -106, -70, 46, 35, 42, -51, 118, -40, 40, 99, -29, -78, -117, -34, -65, -49, -18, -98, -84, 79, -115, -42, 93, 55, -115, -71, 6, 8, 106, -11, -5, 12, 11, -61, -9, -31, -114, 112, -119, 31, 37, 125, -9, 82, -53, 90, -43, 77, -53, -114, 118, 9, -68, 93, -48, 116, -116, 54, -82, 6, -52, 64, -66, 54, -34, 51, -3, -83, 49, -79, 81, -88, -122, -113, 6, -102, -11, 60, -128, 12, -105, -66, 4, -80, -2, -106, -73, 117, 55, -14, 96, 96, 107, -41, 16, 10, -83, -60, -88, -25, 49, -30, 19, 48, -85, -65, -70, -90, 0, -43, 100, 7, -106, 77, 70, -8, -87, 16, 108, 49, 102, -91, 41, -31, -45, 101, 61, -11, 108, -23, -117, 16, 52, -30, -46, -106, 78, 114, 64, -31, -82, 40, -109, 97, 61, -54, 50, -70, -106, -82, -21, -14, 78, -93, 101, -68, 107, 22, 18, 115, 3, 125, 44, -106, 126, -109, 8, -90, -81, 118, -34, 98, -111, -73, -67, -39, -51, -85, -104, 41, -37, 31, -29, 26, -114, -88, -116, -89, 27, -36, 74, -99, 101, -13, 76, 126, 1, -32, 59, 80, -102, -93, -92, 30, -49, -87, -28, -70, 88, 16, 117, 37, -49, 56, -6, 106, -74, -60, -71, -72, -91, -81, -9, -122, 53, -126, 28, -16, -126, -14, -24, -89, 19, -17, 20, 110, -25, 73, -74, 67, -65, 78, 103, 107, 116, -63, 84, -113, -114, -114, 24, 66, -6, -74, -71, 126, -112, 68, -37, 117, -88, 92, -13, 39, 18, -44, 92, 97, -84, -111, -118, -13, -73, -60, 69, -43, 74, 38, -89, 82, 74, 33, -41, 73, 87, 12, -114, 0, -48, 80, 1, -79, -53, -19, -4, 60, -8, 108, -85, -54, 104, 36, 77, -6, 30, 78, -104, 120, 33, 85, -87, -86, -57, -102, 97, -111, 43, 29, -63, 103, 101, 57, 64, 124, 53, -43, 118, 103, 107, 77, -97, 81, 90, 90, -102, 28, -57, 26, 18, -26, -21, 92, 36, -83, 22, 57, -33, 112, 1, -46, -23, -51, 121, 68, 45, -89, -25, -42, 103, 30, -113, -120, 36, 0, 19, 60, -28, 15, -63, -8, 97, -117, -69, -86, -55, -114, -89, -78, -5, -60, 86, 41, 117, -85, -38, -106, 2, -126, -107, 89, -93, -72, 20, 11, 48, 117, -57, -52, -9, 29, 54, -28, -13, 95, -100, 62, 107, -126, -22, -110, 40, -14, -110, 22, -10, -107, -87, -8, 45, -117, -3, -59, 22, 68, 92, 97, 48, -47, 90, 72, -13, 116, 50, 86, -44, -106, 95, -30, -89, 6, -69, 77, -64, 98, -110, 40, -59, -60, 58, 58, -11, -83, 81, -59, 65, 56, 105, 94, -2, 110, 73, 125, 46, 42, -52, 68, -28, 25, 97, -111, -98, -51, -50, 43, -31, -92, -88, 99, 26, -81, -62, 104, -117, -87, 70, -75, 26, -68, 18, -35, -4, 92, 79, -63, -24, 42, 34, 96, 63, -78, 58, -52, -71, 79, -121, 81, 65, 69, -24, -23, 55, -49, 10, 11, 33, -2, -8, 105, -95, -15, 6, 66, -121, 13, -124, -21, -103, -30, -56, -72, -44, 61, -67, -24, 96, -81, 20, -38, -21, -93, -35, 25, -105, -116, -15, -3, 71, 77, 0, -108, 85, 63, -114, 82, 31, -28, -61, -116, 74, 9, -1, -88, 67, 92, 14, 1, -90, -55, 105, -31, 5, -91, 123, 105, 2, -44, 71, 31, 8, 6, -68, 5, -35, 66, 112, 120, -38, 48, 85, 67, 89, -103, -43, 29, 120, 16, -4, 53, 72, -36, -56, 9, 42, -32, -98, -24, 66, 70, 54, -112, 73, -59, -124, 4, -51, 84, -120, 1, -18, -70, 66, -85, 27, 127, -85, -19, 117, -91, -63, 94, -46, 97, -35, -105, -84, -81, -118, -81, 107, 63, 65, -109, -36, -49, 111, -8, 77, 57, -91, -49, 2, 93, 103, 71, 48, 38, 28, 102, 9, -13, 25, 121, 95, -75, 69, -74, -18, -112, -122, -59, 17, -26, 81, 123, 54, 56, -127, -92, 32, 12, 86, 103, -84, 39, -18, 78, 100, 62, -78, -56, 84, -65, 80, -78, 102, -9, -48, 73, -98, 118, 74, 116, 39, -103, -127, 33, 48, -6, -48, 10, -69, -11, 118, -51, 1, -56, -59, -48, 103, -105, -109, -29, -100, 77, 66, 4, -85, -93, 46, -64, 61, -57, -111, -29, 89, -25, 126, -89, 65, -32, 33, -65, -70, 36, -19, -18, -79, 88, -79, 20, -91, -71, 13, -114, -44, 68, -14, -48, 106, -46, 105, 126, -6, -72, 113, -117, -46, 9, 27, -55, 113, 19, -69, -15, 36, -117, -90, 35, 122, 64, -108, -56]
简答为 "no"。
任何字节流 B 都有一个 base64 编码 E。编码流 E 是解码为字节流 B 的唯一有效字节流。这就是 B64 的工作方式。
在您的示例中，您将字符串中的一个字符更改为标准 base64 中无效的字符。解码器如何处理这将是特定于实现的。
您已将该字符更改为无效的 base64 字符。因此结果将是特定于解码器的。
您的测试表明，某些 base64 解码器比其他解码器更能处理无效的 base64 字符。最好的解决方案是使用 Base64 解码器，其记录的错误行为符合您的预期。 Java 8 现在有两个，java.util.Base64 that debuted in Java 8, and some methods in javax.xml.bind.DatatypeConverter that have been around since at least Java 6. There are also other classes out there, such as the iHarder base64 class which has a nice page describing it and other base64 decoders, and the base64 decoder in Apache Commons Codec.
请注意，上面提供的某些库在解码无效的 Base64 字符时也不会抛出异常。这是我通过试验不同的 Base64 库发现的。最终，我通过显式检查我的位翻转是否产生了 Base64 字符解决了这个问题。如果没有，我取消位翻转并选择一个新的位进行翻转。